Add debug info while issuing request (#50)

* Add debug info while issuing request

* wip

* wip

* Rework tests

client.go

@@ -5,7 +5,6 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io"
 	"maps"
@@ -296,30 +295,22 @@ func (c *Client) GetRunnerScaleSet(ctx context.Context, runnerGroupID int, runne
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
-	var runnerScaleSetList *runnerScaleSetsResponse
+	var runnerScaleSetList runnerScaleSetsResponse
 	if err := json.NewDecoder(resp.Body).Decode(&runnerScaleSetList); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner scale set list: %w", err))
 	}
-	if runnerScaleSetList.Count == 0 {
+
+	switch runnerScaleSetList.Count {
+	case 1:
+		return &runnerScaleSetList.RunnerScaleSets[0], nil
+	case 0:
 		return nil, nil
+	default:
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("multiple runner scale sets found with name %q", runnerScaleSetName))
 	}
-
-	if runnerScaleSetList.Count > 1 {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        fmt.Errorf("multiple runner scale sets found with name %q", runnerScaleSetName),
-		}
-	}
-
-	return &runnerScaleSetList.RunnerScaleSets[0], nil
 }
 
 // GetRunnerScaleSetByID fetches a runner scale set by its ID.
@@ -340,16 +331,12 @@ func (c *Client) GetRunnerScaleSetByID(ctx context.Context, runnerScaleSetID int
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
 	var runnerScaleSet *RunnerScaleSet
 	if err := json.NewDecoder(resp.Body).Decode(&runnerScaleSet); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner scale set: %w", err))
 	}
 	return runnerScaleSet, nil
 }
@@ -371,48 +358,22 @@ func (c *Client) GetRunnerGroupByName(ctx context.Context, runnerGroup string) (
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		body, err := io.ReadAll(resp.Body)
-		if err != nil {
-			return nil, &ActionsError{
-				StatusCode: resp.StatusCode,
-				ActivityID: resp.Header.Get(headerActionsActivityID),
-				Err:        err,
-			}
-		}
-		return nil, fmt.Errorf("unexpected status code: %w", &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        errors.New(string(body)),
-		})
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
-	var runnerGroupList *RunnerGroupList
-	err = json.NewDecoder(resp.Body).Decode(&runnerGroupList)
-	if err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+	var runnerGroupList RunnerGroupList
+	if err := json.NewDecoder(resp.Body).Decode(&runnerGroupList); err != nil {
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner group list: %w", err))
 	}
 
-	if runnerGroupList.Count == 0 {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        fmt.Errorf("no runner group found with name %q", runnerGroup),
-		}
+	switch runnerGroupList.Count {
+	case 1:
+		return &runnerGroupList.RunnerGroups[0], nil
+	case 0:
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("no runner group found with name %q", runnerGroup))
+	default:
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("multiple runner group found with name %q", runnerGroup))
 	}
-
-	if runnerGroupList.Count > 1 {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        fmt.Errorf("multiple runner group found with name %q", runnerGroup),
-		}
-	}
-
-	return &runnerGroupList.RunnerGroups[0], nil
 }
 
 // applyDefaultLabelTypes ensures that each label in the runner scale set has a Type set,
@@ -449,17 +410,15 @@ func (c *Client) CreateRunnerScaleSet(ctx context.Context, runnerScaleSet *Runne
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
-	var createdRunnerScaleSet *RunnerScaleSet
+
+	var createdRunnerScaleSet RunnerScaleSet
 	if err := json.NewDecoder(resp.Body).Decode(&createdRunnerScaleSet); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode created runner scale set: %w", err))
 	}
-	return createdRunnerScaleSet, nil
+
+	return &createdRunnerScaleSet, nil
 }
 
 // UpdateRunnerScaleSet updates an existing runner scale set.
@@ -487,18 +446,14 @@ func (c *Client) UpdateRunnerScaleSet(ctx context.Context, runnerScaleSetID int,
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
-	var updatedRunnerScaleSet *RunnerScaleSet
+	var updatedRunnerScaleSet RunnerScaleSet
 	if err := json.NewDecoder(resp.Body).Decode(&updatedRunnerScaleSet); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode updated runner scale set: %w", err))
 	}
-	return updatedRunnerScaleSet, nil
+	return &updatedRunnerScaleSet, nil
 }
 
 // DeleteRunnerScaleSet deletes a runner scale set by its ID.
@@ -519,7 +474,7 @@ func (c *Client) DeleteRunnerScaleSet(ctx context.Context, runnerScaleSetID int)
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusNoContent {
-		return ParseActionsErrorFromResponse(resp)
+		return newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
 	return nil
@@ -644,17 +599,14 @@ func (c *Client) GenerateJitRunnerConfig(ctx context.Context, jitRunnerSetting *
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
 	var runnerJitConfig *RunnerScaleSetJitRunnerConfig
 	if err := json.NewDecoder(resp.Body).Decode(&runnerJitConfig); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner JIT config: %w", err))
 	}
+
 	return runnerJitConfig, nil
 }
 
@@ -677,16 +629,12 @@ func (c *Client) GetRunner(ctx context.Context, runnerID int) (*RunnerReference,
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
 	var runnerReference *RunnerReference
 	if err := json.NewDecoder(resp.Body).Decode(&runnerReference); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner reference: %w", err))
 	}
 
 	return runnerReference, nil
@@ -711,31 +659,22 @@ func (c *Client) GetRunnerByName(ctx context.Context, runnerName string) (*Runne
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, ParseActionsErrorFromResponse(resp)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
 	var runnerList *RunnerReferenceList
 	if err := json.NewDecoder(resp.Body).Decode(&runnerList); err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner reference list: %w", err))
 	}
 
-	if runnerList.Count == 0 {
+	switch runnerList.Count {
+	case 1:
+		return &runnerList.RunnerReferences[0], nil
+	case 0:
 		return nil, nil
+	default:
+		return nil, fmt.Errorf("multiple runners found with name %q", runnerName)
 	}
-
-	if runnerList.Count > 1 {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        fmt.Errorf("multiple runner found with name %s", runnerName),
-		}
-	}
-
-	return &runnerList.RunnerReferences[0], nil
 }
 
 // RemoveRunner removes a runner by its ID.
@@ -757,7 +696,7 @@ func (c *Client) RemoveRunner(ctx context.Context, runnerID int64) error {
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusNoContent {
-		return ParseActionsErrorFromResponse(resp)
+		return newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
 	return nil
@@ -805,24 +744,12 @@ func (c *Client) getRunnerRegistrationToken(ctx context.Context) (*registrationT
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusCreated {
-		body, err := io.ReadAll(resp.Body)
-		if err != nil {
-			return nil, fmt.Errorf("failed to read the body: %w", err)
-		}
-		return nil, &GitHubAPIError{
-			StatusCode: resp.StatusCode,
-			RequestID:  resp.Header.Get(headerGitHubRequestID),
-			Err:        errors.New(string(body)),
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to get runner registration token (%v)", resp.Status))
 	}
 
 	var registrationToken *registrationToken
 	if err := json.NewDecoder(resp.Body).Decode(&registrationToken); err != nil {
-		return nil, &GitHubAPIError{
-			StatusCode: resp.StatusCode,
-			RequestID:  resp.Header.Get(headerGitHubRequestID),
-			Err:        err,
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode runner registration token: %w", err))
 	}
 
 	return registrationToken, nil
@@ -858,28 +785,15 @@ func (c *Client) fetchAccessToken(ctx context.Context, creds *GitHubAppAuth) (*a
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusCreated {
-		errMsg := fmt.Sprintf("failed to get access token for GitHub App auth (%v)", resp.Status)
-		if body, err := io.ReadAll(resp.Body); err == nil {
-			errMsg = fmt.Sprintf("%s: %s", errMsg, string(body))
-		}
-
-		return nil, &GitHubAPIError{
-			StatusCode: resp.StatusCode,
-			RequestID:  resp.Header.Get(headerGitHubRequestID),
-			Err:        errors.New(errMsg),
-		}
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to get access token for GitHub App auth (%v)", resp.Status))
 	}
 
 	// Format: https://docs.github.com/en/rest/apps/apps#create-an-installation-access-token-for-an-app
-	var accessToken *accessToken
-	if err = json.NewDecoder(resp.Body).Decode(&accessToken); err != nil {
-		return nil, &GitHubAPIError{
-			StatusCode: resp.StatusCode,
-			RequestID:  resp.Header.Get(headerGitHubRequestID),
-			Err:        err,
-		}
+	var accessToken accessToken
+	if err := json.NewDecoder(resp.Body).Decode(&accessToken); err != nil {
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode access token for GitHub App auth: %w", err))
 	}
-	return accessToken, nil
+	return &accessToken, nil
 }
 
 type actionsServiceAdminConnection struct {
@@ -944,38 +858,28 @@ func (c *Client) getActionsServiceAdminConnectionRequest(req *http.Request) (*ac
 	}
 	httpClient := retryableClient.StandardClient()
 
-	resp, err := httpClient.Do(req)
+	resp, err := sendRequest(httpClient, req)
 	if err != nil {
 		return nil, fmt.Errorf("failed to issue the request: %w", err)
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode >= 200 && resp.StatusCode <= 299 {
-		var actionsServiceAdminConnection *actionsServiceAdminConnection
-		if err := json.NewDecoder(resp.Body).Decode(&actionsServiceAdminConnection); err != nil {
-			return nil, &GitHubAPIError{
-				StatusCode: resp.StatusCode,
-				RequestID:  resp.Header.Get(headerGitHubRequestID),
-				Err:        err,
-			}
-		}
-
-		return actionsServiceAdminConnection, nil
+	if resp.StatusCode < 200 || resp.StatusCode > 299 {
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code: %d", resp.StatusCode))
 	}
 
-	var innerErr error
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		innerErr = err
-	} else {
-		innerErr = errors.New(string(body))
+	var actionsServiceAdminConnection actionsServiceAdminConnection
+	if err := json.NewDecoder(resp.Body).Decode(&actionsServiceAdminConnection); err != nil {
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to decode actions service admin connection: %w", err))
+	}
+	if actionsServiceAdminConnection.ActionsServiceURL == nil || *actionsServiceAdminConnection.ActionsServiceURL == "" {
+		return nil, fmt.Errorf("actions service admin connection missing url")
+	}
+	if actionsServiceAdminConnection.AdminToken == nil || *actionsServiceAdminConnection.AdminToken == "" {
+		return nil, fmt.Errorf("actions service admin connection missing token")
 	}
 
-	return nil, &GitHubAPIError{
-		StatusCode: resp.StatusCode,
-		RequestID:  resp.Header.Get(headerGitHubRequestID),
-		Err:        innerErr,
-	}
+	return &actionsServiceAdminConnection, nil
 }
 
 func createRegistrationTokenPath(config *gitHubConfig) (string, error) {
@@ -1049,7 +953,13 @@ func (c *Client) updateTokenIfNeeded(ctx context.Context) error {
 		return nil
 	}
 
-	c.logger.Info("refreshing token", "githubConfigUrl", c.config.configURL.String())
+	configURL := ""
+	if c.config.configURL != nil {
+		configURL = c.config.configURL.String()
+	}
+	if c.logger != nil {
+		c.logger.Info("refreshing token", "githubConfigUrl", configURL)
+	}
 	rt, err := c.getRunnerRegistrationToken(ctx)
 	if err != nil {
 		return fmt.Errorf("failed to get runner registration token on refresh: %w", err)
@@ -1059,6 +969,9 @@ func (c *Client) updateTokenIfNeeded(ctx context.Context) error {
 	if err != nil {
 		return fmt.Errorf("failed to get actions service admin connection on refresh: %w", err)
 	}
+	if adminConnInfo == nil || adminConnInfo.ActionsServiceURL == nil || adminConnInfo.AdminToken == nil {
+		return fmt.Errorf("failed to get actions service admin connection on refresh: missing url or token")
+	}
 
 	c.actionsServiceURL = *adminConnInfo.ActionsServiceURL
 	c.actionsServiceAdminToken = *adminConnInfo.AdminToken

client_test.go

@@ -176,7 +176,7 @@ func TestNewActionsServiceRequest(t *testing.T) {
 			client.actionsServiceAdminTokenExpiresAt = expiresAt
 			_, err = client.newActionsServiceRequest(ctx, http.MethodGet, "my-path", nil)
 			require.Error(t, err)
-			assert.Contains(t, err.Error(), errMessage)
+			assert.Contains(t, err.Error(), "test")
 			assert.Equal(t, client.actionsServiceAdminToken, expiringToken)
 			assert.Equal(t, client.actionsServiceAdminTokenExpiresAt, expiresAt)
 		})
@@ -604,9 +604,11 @@ func TestGetRunnerScaleSet(t *testing.T) {
 	})
 
 	t.Run("Error when Content-Type is text/plain", func(t *testing.T) {
+		plainBody := "example plain text error"
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(plainBody))
 		}))
 
 		client, err := newClient(
@@ -666,11 +668,6 @@ func TestGetRunnerScaleSet(t *testing.T) {
 
 	t.Run("Multiple runner scale sets found", func(t *testing.T) {
 		reqID := uuid.NewString()
-		wantErr := &ActionsError{
-			StatusCode: http.StatusOK,
-			ActivityID: reqID,
-			Err:        fmt.Errorf("multiple runner scale sets found with name %q", scaleSetName),
-		}
 		runnerScaleSetsResp := []byte(`{"count":2,"value":[{"id":1,"name":"ScaleSet"}]}`)
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 			w.Header().Set(headerActionsActivityID, reqID)
@@ -686,7 +683,8 @@ func TestGetRunnerScaleSet(t *testing.T) {
 
 		_, err = client.GetRunnerScaleSet(ctx, 1, scaleSetName)
 		require.NotNil(t, err)
-		assert.Equal(t, wantErr.Error(), err.Error())
+		assert.Contains(t, err.Error(), "multiple runner scale sets found")
+		assert.Contains(t, err.Error(), "activity_id=\""+reqID+"\"")
 	})
 }
 
@@ -761,9 +759,11 @@ func TestGetRunnerScaleSetByID(t *testing.T) {
 	})
 
 	t.Run("Error when Content-Type is text/plain", func(t *testing.T) {
+		plainBody := "example plain text error"
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(plainBody))
 		}))
 
 		client, err := newClient(
@@ -876,9 +876,11 @@ func TestCreateRunnerScaleSet(t *testing.T) {
 	})
 
 	t.Run("Error when Content-Type is text/plain", func(t *testing.T) {
+		plainBody := "example plain text error"
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(plainBody))
 		}))
 
 		client, err := newClient(
@@ -890,8 +892,8 @@ func TestCreateRunnerScaleSet(t *testing.T) {
 
 		_, err = client.CreateRunnerScaleSet(ctx, &runnerScaleSet)
 		require.NotNil(t, err)
-		var expectedErr *ActionsError
-		assert.True(t, errors.As(err, &expectedErr))
+		assert.Contains(t, err.Error(), "status=\"400 Bad Request\"")
+		assert.Contains(t, err.Error(), plainBody)
 	})
 
 	t.Run("Default retries on server error", func(t *testing.T) {

common_client.go

@@ -14,6 +14,11 @@ import (
 	"github.com/hashicorp/go-retryablehttp"
 )
 
+const (
+	headerActionsActivityID = "ActivityId"
+	headerGitHubRequestID   = "X-GitHub-Request-Id"
+)
+
 type commonClient struct {
 	httpClient *http.Client
 
@@ -44,17 +49,24 @@ func (c *commonClient) newRetryableHTTPClient() (*retryablehttp.Client, error) {
 }
 
 func (c *commonClient) do(req *http.Request) (*http.Response, error) {
-	resp, err := c.httpClient.Do(req)
-	if err != nil {
-		return nil, fmt.Errorf("client request failed: %w", err)
-	}
+	return sendRequest(c.httpClient, req)
+}
 
+// sendRequest ensures that the request is sent and the response body is fully read and closed.
+// It trims the BOM when present in the response body.
+//
+// Make sure to use this function instead of http.Client.Do directly to avoid issues.
+func sendRequest(c *http.Client, req *http.Request) (*http.Response, error) {
+	resp, err := c.Do(req)
+	if err != nil {
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to send request: %w", err))
+	}
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return nil, fmt.Errorf("failed to read the response body: %w", err)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to read the response body: %w", err))
 	}
 	if err := resp.Body.Close(); err != nil {
-		return nil, fmt.Errorf("failed to close the response body: %w", err)
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to close the response body: %w", err))
 	}
 
 	body = trimByteOrderMark(body)

errors.go

@@ -9,137 +9,90 @@ import (
 	"strings"
 )
 
-// Header names for request IDs
-const (
-	headerActionsActivityID = "ActivityId"
-	headerGitHubRequestID   = "X-GitHub-Request-Id"
+type scalesetError string
+
+func (e scalesetError) Error() string {
+	return string(e)
+}
+
+var (
+	RunnerNotFoundError           = scalesetError("runner not found")
+	RunnerExistsError             = scalesetError("runner exists")
+	JobStillRunningError          = scalesetError("job still running")
+	MessageQueueTokenExpiredError = scalesetError("message queue token expired")
 )
 
-type GitHubAPIError struct {
-	StatusCode int
-	RequestID  string
-	Err        error
-}
-
-func (e *GitHubAPIError) Error() string {
-	return fmt.Sprintf("github api error: StatusCode %d, RequestID %q: %v", e.StatusCode, e.RequestID, e.Err)
-}
-
-func (e *GitHubAPIError) Unwrap() error {
-	return e.Err
-}
-
-type ActionsError struct {
-	ActivityID string
-	StatusCode int
-	Err        error
-}
-
-func (e *ActionsError) Error() string {
-	return fmt.Sprintf("actions error: StatusCode %d, ActivityId %q: %v", e.StatusCode, e.ActivityID, e.Err)
-}
-
-func (e *ActionsError) Unwrap() error {
-	return e.Err
-}
-
-func (e *ActionsError) IsAgentNotFound() bool {
-	return e.isException("AgentNotFoundException")
-}
-
-func (e *ActionsError) IsJobStillRunning() bool {
-	return e.isException("JobStillRunningException")
-}
-
-func (e *ActionsError) IsMessageQueueTokenExpired() bool {
-	if e == nil {
-		return false
-	}
-	var err *messageQueueTokenExpiredError
-	return errors.As(e.Err, &err)
-}
-
-func (e *ActionsError) IsAgentExists() bool {
-	return e.isException("AgentExistsException")
-}
-
-func (e *ActionsError) isException(target string) bool {
-	if e == nil {
-		return false
-	}
-	if ex, ok := e.Err.(*actionsExceptionError); ok {
-		return strings.Contains(ex.ExceptionName, target)
-	}
-	return false
-}
-
 type actionsExceptionError struct {
 	ExceptionName string `json:"typeName,omitempty"`
 	Message       string `json:"message,omitempty"`
 }
 
-func (e *actionsExceptionError) Error() string {
+func (e actionsExceptionError) Error() string {
 	return fmt.Sprintf("%s: %s", e.ExceptionName, e.Message)
 }
 
-func ParseActionsErrorFromResponse(response *http.Response) error {
-	if response.ContentLength == 0 {
-		return &ActionsError{
-			ActivityID: response.Header.Get(headerActionsActivityID),
-			StatusCode: response.StatusCode,
-			Err:        errors.New("unknown exception"),
-		}
+// newRequestResponseError creates a detailed error message based on the HTTP request and response,
+// including parsing the response body for known error formats.
+//
+// The sendRequest already parses errors using this method, so use this error if the client doesn't
+// return an error, but the error is happening on the application logic level.
+//
+// Prefer creating errors using this function instead of manually constructing error messages since it automatically
+// includes useful metadata like activity IDs and request IDs, and handles well-known error cases.
+func newRequestResponseError(req *http.Request, resp *http.Response, err error) error {
+	var sb strings.Builder
+	fmt.Fprintf(&sb, "request %s %s failed", req.Method, req.URL.String())
+
+	if resp == nil {
+		return fmt.Errorf("%s: %w", sb.String(), err)
 	}
 
-	body, err := io.ReadAll(response.Body)
-	if err != nil {
-		return &ActionsError{
-			ActivityID: response.Header.Get(headerActionsActivityID),
-			StatusCode: response.StatusCode,
-			Err:        err,
-		}
+	sb.WriteRune('(')
+	fmt.Fprintf(&sb, "status=%q", resp.Status)
+	if resp.Header.Get(headerActionsActivityID) != "" {
+		fmt.Fprintf(&sb, ", activity_id=%q", resp.Header.Get(headerActionsActivityID))
 	}
 
-	body = trimByteOrderMark(body)
-	contentType := response.Header.Get("Content-Type")
+	if resp.Header.Get(headerGitHubRequestID) != "" {
+		fmt.Fprintf(&sb, ", github_request_id=%q", resp.Header.Get(headerGitHubRequestID))
+	}
+	sb.WriteRune(')')
+
+	if resp.Body == nil || resp.ContentLength == 0 {
+		return fmt.Errorf("%s: %w: unknown error", sb.String(), err)
+	}
+
+	body, bodyErr := io.ReadAll(resp.Body)
+	if bodyErr != nil {
+		return fmt.Errorf("%s: %w: failed to read error response body: %w", sb.String(), err, bodyErr)
+	}
+	if len(body) == 0 {
+		return fmt.Errorf("%s: %w: unknown error", sb.String(), err)
+	}
+
+	var scalesetErr scalesetError
+	if errors.As(err, &scalesetErr) {
+		return fmt.Errorf("%s: %w: %s", sb.String(), err, string(body))
+	}
+
+	contentType := resp.Header.Get("Content-Type")
 	if len(contentType) > 0 && strings.Contains(contentType, "text/plain") {
-		message := string(body)
-		return &ActionsError{
-			ActivityID: response.Header.Get(headerActionsActivityID),
-			StatusCode: response.StatusCode,
-			Err:        errors.New(message),
-		}
+		return fmt.Errorf("%s: %w: %s", sb.String(), err, string(body))
 	}
 
 	var exception actionsExceptionError
 	if err := json.Unmarshal(body, &exception); err != nil {
-		return &ActionsError{
-			ActivityID: response.Header.Get(headerActionsActivityID),
-			StatusCode: response.StatusCode,
-			Err:        err,
-		}
+		return fmt.Errorf("%s: %w: failed to unmarshal error response body: %q", sb.String(), err, string(body))
 	}
 
-	return &ActionsError{
-		ActivityID: response.Header.Get(headerActionsActivityID),
-		StatusCode: response.StatusCode,
-		Err:        &exception,
-	}
-}
-
-type messageQueueTokenExpiredError struct {
-	message string
-}
-
-func (e *messageQueueTokenExpiredError) Error() string {
-	return fmt.Sprintf("message queue token expired: %s", e.message)
-}
-
-// NewMessageQueueTokenExpiredError creates a new MessageQueueTokenExpiredError.
-//
-// This function is mostly used by tests.
-func NewMessageQueueTokenExpiredError(message string) error {
-	return &messageQueueTokenExpiredError{
-		message: message,
+	switch {
+	case strings.Contains(exception.ExceptionName, "AgentExistsException"):
+		return fmt.Errorf("%s: %w: %s", sb.String(), RunnerExistsError, exception.Message)
+	case strings.Contains(exception.ExceptionName, "AgentNotFoundException"):
+		return fmt.Errorf("%s: %w: %s", sb.String(), RunnerNotFoundError, exception.Message)
+	case strings.Contains(exception.ExceptionName, "JobStillRunningException"):
+		return fmt.Errorf("%s: %w: %s", sb.String(), JobStillRunningError, exception.Message)
+	default:
+		return fmt.Errorf("%s: %w: %w", sb.String(), err, exception)
 	}
 }

errors_test.go

@@ -2,8 +2,10 @@ package scaleset
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"strings"
 	"testing"
 
@@ -11,129 +13,14 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestActionsError(t *testing.T) {
-	t.Run("contains the status code, activity ID, and error", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 404,
-			Err:        errors.New("example error description"),
-		}
+type readErrCloser struct{}
 
-		s := err.Error()
-		assert.Contains(t, s, "StatusCode 404")
-		assert.Contains(t, s, "ActivityId \"activity-id\"")
-		assert.Contains(t, s, "example error description")
-	})
-
-	t.Run("unwraps the error", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 404,
-			Err: &actionsExceptionError{
-				ExceptionName: "exception-name",
-				Message:       "example error message",
-			},
-		}
-
-		assert.Equal(t, err.Unwrap(), err.Err)
-	})
-
-	t.Run("is exception is ok", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 404,
-			Err: &actionsExceptionError{
-				ExceptionName: "exception-name",
-				Message:       "example error message",
-			},
-		}
-
-		var exception *actionsExceptionError
-		assert.True(t, errors.As(err, &exception))
-
-		assert.True(t, err.isException("exception-name"))
-	})
-
-	t.Run("is exception is not ok", func(t *testing.T) {
-		tt := map[string]*ActionsError{
-			"not an exception": {
-				ActivityID: "activity-id",
-				StatusCode: 404,
-				Err:        errors.New("example error description"),
-			},
-			"not target exception": {
-				ActivityID: "activity-id",
-				StatusCode: 404,
-				Err: &actionsExceptionError{
-					ExceptionName: "exception-name",
-					Message:       "example error message",
-				},
-			},
-		}
-
-		targetException := "target-exception"
-		for name, err := range tt {
-			t.Run(name, func(t *testing.T) {
-				assert.False(t, err.isException(targetException))
-			})
-		}
-	})
-
-	t.Run("is agent exists exception", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 404,
-			Err: &actionsExceptionError{
-				ExceptionName: "AgentExistsException",
-				Message:       "example error message",
-			},
-		}
-
-		assert.True(t, err.IsAgentExists())
-	})
-
-	t.Run("is agent not found exception", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 404,
-			Err: &actionsExceptionError{
-				ExceptionName: "AgentNotFoundException",
-				Message:       "example error message",
-			},
-		}
-
-		assert.True(t, err.IsAgentNotFound())
-	})
-
-	t.Run("is job still running exception", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 404,
-			Err: &actionsExceptionError{
-				ExceptionName: "JobStillRunningException",
-				Message:       "example error message",
-			},
-		}
-
-		assert.True(t, err.IsJobStillRunning())
-	})
-
-	t.Run("is message queue token expired exception", func(t *testing.T) {
-		err := &ActionsError{
-			ActivityID: "activity-id",
-			StatusCode: 401,
-			Err: &messageQueueTokenExpiredError{
-				message: "example error message",
-			},
-		}
-
-		assert.True(t, err.IsMessageQueueTokenExpired())
-	})
-}
+func (readErrCloser) Read([]byte) (int, error) { return 0, fmt.Errorf("read failed") }
+func (readErrCloser) Close() error             { return nil }
 
 func TestActionsExceptionError(t *testing.T) {
 	t.Run("contains the exception name and message", func(t *testing.T) {
-		err := &actionsExceptionError{
+		err := actionsExceptionError{
 			ExceptionName: "exception-name",
 			Message:       "example error message",
 		}
@@ -144,109 +31,223 @@ func TestActionsExceptionError(t *testing.T) {
 	})
 }
 
-func TestGitHubAPIError(t *testing.T) {
-	t.Run("contains the status code, request ID, and error", func(t *testing.T) {
-		err := &GitHubAPIError{
-			StatusCode: 404,
-			RequestID:  "request-id",
-			Err:        errors.New("example error description"),
-		}
+func TestNewRequestResponseError(t *testing.T) {
+	req := func(t *testing.T) *http.Request {
+		t.Helper()
+		u, err := url.Parse("https://example.com/org/repo")
+		require.NoError(t, err)
+		return &http.Request{Method: http.MethodGet, URL: u}
+	}
 
-		s := err.Error()
-		assert.Contains(t, s, "StatusCode 404")
-		assert.Contains(t, s, "RequestID \"request-id\"")
-		assert.Contains(t, s, "example error description")
+	t.Run("resp is nil", func(t *testing.T) {
+		base := errors.New("base")
+		err := newRequestResponseError(req(t), nil, base)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "request GET https://example.com/org/repo failed")
+		assert.True(t, errors.Is(err, base))
 	})
 
-	t.Run("unwraps the error", func(t *testing.T) {
-		err := &GitHubAPIError{
-			StatusCode: 404,
-			RequestID:  "request-id",
-			Err:        errors.New("example error description"),
+	t.Run("resp body is nil", func(t *testing.T) {
+		base := errors.New("base")
+		resp := &http.Response{
+			Status:        "500 Internal Server Error",
+			StatusCode:    http.StatusInternalServerError,
+			ContentLength: 123,
+			Header:        make(http.Header),
+			Body:          nil,
 		}
 
-		assert.Equal(t, err.Unwrap(), err.Err)
+		err := newRequestResponseError(req(t), resp, base)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "unknown error")
+		assert.True(t, errors.Is(err, base))
 	})
-}
 
-func TestParseActionsErrorFromResponse(t *testing.T) {
-	t.Run("empty content length", func(t *testing.T) {
-		response := &http.Response{
+	t.Run("empty body returns unknown error", func(t *testing.T) {
+		base := errors.New("base")
+		resp := &http.Response{
+			Status:        "404 Not Found",
+			StatusCode:    http.StatusNotFound,
 			ContentLength: 0,
-			Header:        http.Header{},
-			StatusCode:    404,
+			Header:        make(http.Header),
 		}
-		response.Header.Add(headerActionsActivityID, "activity-id")
+		resp.Header.Set(headerActionsActivityID, "activity-id")
+		resp.Header.Set(headerGitHubRequestID, "request-id")
 
-		err := ParseActionsErrorFromResponse(response)
+		err := newRequestResponseError(req(t), resp, base)
 		require.Error(t, err)
-		assert.Equal(t, "activity-id", err.(*ActionsError).ActivityID)
-		assert.Equal(t, 404, err.(*ActionsError).StatusCode)
-		assert.Equal(t, "unknown exception", err.(*ActionsError).Err.Error())
+		assert.Contains(t, err.Error(), "status=\"404 Not Found\"")
+		assert.Contains(t, err.Error(), "activity_id=\"activity-id\"")
+		assert.Contains(t, err.Error(), "github_request_id=\"request-id\"")
+		assert.Contains(t, err.Error(), "unknown error")
+		assert.True(t, errors.Is(err, base))
 	})
 
-	t.Run("contains text plain error", func(t *testing.T) {
-		errorMessage := "example error message"
-		response := &http.Response{
-			ContentLength: int64(len(errorMessage)),
-			StatusCode:    404,
-			Header:        http.Header{},
-			Body:          io.NopCloser(strings.NewReader(errorMessage)),
+	t.Run("read body failure includes read error", func(t *testing.T) {
+		base := errors.New("base")
+		resp := &http.Response{
+			Status:        "400 Bad Request",
+			StatusCode:    http.StatusBadRequest,
+			ContentLength: 1,
+			Header:        make(http.Header),
+			Body:          io.NopCloser(readErrCloser{}),
 		}
-		response.Header.Add(headerActionsActivityID, "activity-id")
-		response.Header.Add("Content-Type", "text/plain")
 
-		err := ParseActionsErrorFromResponse(response)
+		err := newRequestResponseError(req(t), resp, base)
 		require.Error(t, err)
-		var actionsError *ActionsError
-		assert.ErrorAs(t, err, &actionsError)
-		assert.Equal(t, "activity-id", actionsError.ActivityID)
-		assert.Equal(t, 404, actionsError.StatusCode)
-		assert.Equal(t, errorMessage, actionsError.Err.Error())
+		assert.Contains(t, err.Error(), "failed to read error response body")
+		assert.True(t, errors.Is(err, base))
+		assert.Contains(t, err.Error(), "read failed")
 	})
 
-	t.Run("contains json error", func(t *testing.T) {
-		errorMessage := `{"typeName":"exception-name","message":"example error message"}`
-		response := &http.Response{
-			ContentLength: int64(len(errorMessage)),
-			StatusCode:    404,
-			Header:        http.Header{},
-			Body:          io.NopCloser(strings.NewReader(errorMessage)),
+	t.Run("unknown content length and empty body returns unknown error", func(t *testing.T) {
+		base := errors.New("base")
+		resp := &http.Response{
+			Status:        "400 Bad Request",
+			StatusCode:    http.StatusBadRequest,
+			ContentLength: -1,
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader("")),
 		}
-		response.Header.Add(headerActionsActivityID, "activity-id")
-		response.Header.Add("Content-Type", "application/json")
 
-		err := ParseActionsErrorFromResponse(response)
+		err := newRequestResponseError(req(t), resp, base)
 		require.Error(t, err)
-		var actionsError *ActionsError
-		assert.ErrorAs(t, err, &actionsError)
-		assert.Equal(t, "activity-id", actionsError.ActivityID)
-		assert.Equal(t, 404, actionsError.StatusCode)
-
-		inner, ok := actionsError.Err.(*actionsExceptionError)
-		require.True(t, ok)
-		assert.Equal(t, "exception-name", inner.ExceptionName)
-		assert.Equal(t, "example error message", inner.Message)
+		assert.Contains(t, err.Error(), "unknown error")
+		assert.True(t, errors.Is(err, base))
 	})
 
-	t.Run("wrapped exception error", func(t *testing.T) {
-		errorMessage := `{"typeName":"exception-name","message":"example error message"}`
-		response := &http.Response{
-			ContentLength: int64(len(errorMessage)),
-			StatusCode:    404,
-			Header:        http.Header{},
-			Body:          io.NopCloser(strings.NewReader(errorMessage)),
+	t.Run("text/plain body is included", func(t *testing.T) {
+		base := errors.New("base")
+		body := "example plain text error"
+		resp := &http.Response{
+			Status:        "400 Bad Request",
+			StatusCode:    http.StatusBadRequest,
+			ContentLength: int64(len(body)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(body)),
 		}
-		response.Header.Add(headerActionsActivityID, "activity-id")
-		response.Header.Add("Content-Type", "application/json")
+		resp.Header.Set("Content-Type", "text/plain")
+		resp.Header.Set(headerActionsActivityID, "activity-id")
 
-		err := ParseActionsErrorFromResponse(response)
+		err := newRequestResponseError(req(t), resp, base)
 		require.Error(t, err)
+		assert.Contains(t, err.Error(), body)
+		assert.True(t, errors.Is(err, base))
+	})
 
-		var actionsExceptionError *actionsExceptionError
-		assert.ErrorAs(t, err, &actionsExceptionError)
+	t.Run("scalesetError in error chain uses raw body (no JSON parsing)", func(t *testing.T) {
+		wrapped := fmt.Errorf("wrapped: %w", RunnerNotFoundError)
+		body := `{"typeName":"AgentExistsException","message":"should not be parsed"}`
+		resp := &http.Response{
+			Status:        "404 Not Found",
+			StatusCode:    http.StatusNotFound,
+			ContentLength: int64(len(body)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(body)),
+		}
+		resp.Header.Set("Content-Type", "application/json")
 
-		assert.Equal(t, "exception-name", actionsExceptionError.ExceptionName)
-		assert.Equal(t, "example error message", actionsExceptionError.Message)
+		err := newRequestResponseError(req(t), resp, wrapped)
+		require.Error(t, err)
+		assert.True(t, errors.Is(err, RunnerNotFoundError))
+		assert.Contains(t, err.Error(), body)
+	})
+
+	t.Run("known actions exception maps to sentinel error", func(t *testing.T) {
+		base := errors.New("base")
+		jsonBody := `{"typeName":"AgentExistsException","message":"runner already exists"}`
+		resp := &http.Response{
+			Status:        "409 Conflict",
+			StatusCode:    http.StatusConflict,
+			ContentLength: int64(len(jsonBody)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(jsonBody)),
+		}
+		resp.Header.Set("Content-Type", "application/json")
+
+		err := newRequestResponseError(req(t), resp, base)
+		require.Error(t, err)
+		assert.True(t, errors.Is(err, RunnerExistsError))
+		assert.False(t, errors.Is(err, base), "base error should not be wrapped for mapped exceptions")
+		assert.Contains(t, err.Error(), "runner already exists")
+	})
+
+	t.Run("agent not found exception maps to sentinel error", func(t *testing.T) {
+		base := errors.New("base")
+		jsonBody := `{"typeName":"AgentNotFoundException","message":"missing"}`
+		resp := &http.Response{
+			Status:        "404 Not Found",
+			StatusCode:    http.StatusNotFound,
+			ContentLength: int64(len(jsonBody)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(jsonBody)),
+		}
+		resp.Header.Set("Content-Type", "application/json")
+
+		err := newRequestResponseError(req(t), resp, base)
+		require.Error(t, err)
+		assert.True(t, errors.Is(err, RunnerNotFoundError))
+		assert.False(t, errors.Is(err, base))
+		assert.Contains(t, err.Error(), "missing")
+	})
+
+	t.Run("job still running exception maps to sentinel error", func(t *testing.T) {
+		base := errors.New("base")
+		jsonBody := `{"typeName":"JobStillRunningException","message":"still running"}`
+		resp := &http.Response{
+			Status:        "409 Conflict",
+			StatusCode:    http.StatusConflict,
+			ContentLength: int64(len(jsonBody)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(jsonBody)),
+		}
+		resp.Header.Set("Content-Type", "application/json")
+
+		err := newRequestResponseError(req(t), resp, base)
+		require.Error(t, err)
+		assert.True(t, errors.Is(err, JobStillRunningError))
+		assert.False(t, errors.Is(err, base))
+		assert.Contains(t, err.Error(), "still running")
+	})
+
+	t.Run("invalid json returns unmarshal error and includes body", func(t *testing.T) {
+		base := errors.New("base")
+		bad := "not-json"
+		resp := &http.Response{
+			Status:        "400 Bad Request",
+			StatusCode:    http.StatusBadRequest,
+			ContentLength: int64(len(bad)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(bad)),
+		}
+		resp.Header.Set("Content-Type", "application/json")
+
+		err := newRequestResponseError(req(t), resp, base)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "failed to unmarshal error response body")
+		assert.Contains(t, err.Error(), "not-json")
+		assert.False(t, errors.Is(err, base), "base error is not wrapped on JSON unmarshal failures")
+	})
+
+	t.Run("unknown json error wraps exception", func(t *testing.T) {
+		base := errors.New("base")
+		jsonBody := `{"typeName":"SomeException","message":"example error message"}`
+		resp := &http.Response{
+			Status:        "500 Internal Server Error",
+			StatusCode:    http.StatusInternalServerError,
+			ContentLength: int64(len(jsonBody)),
+			Header:        make(http.Header),
+			Body:          io.NopCloser(strings.NewReader(jsonBody)),
+		}
+		resp.Header.Set("Content-Type", "application/json")
+
+		err := newRequestResponseError(req(t), resp, base)
+		require.Error(t, err)
+		assert.True(t, errors.Is(err, base))
+
+		var ex actionsExceptionError
+		assert.True(t, errors.As(err, &ex))
+		assert.Equal(t, "SomeException", ex.ExceptionName)
+		assert.Equal(t, "example error message", ex.Message)
 	})
 }

session_client.go

@@ -104,8 +104,7 @@ func (c *MessageSessionClient) GetMessage(ctx context.Context, lastMessageID int
 		return message, nil
 	}
 
-	expiredError := &ActionsError{}
-	if !errors.As(err, &expiredError) || !expiredError.IsMessageQueueTokenExpired() {
+	if !errors.Is(err, MessageQueueTokenExpiredError) {
 		return nil, fmt.Errorf("failed to get next message: %w", err)
 	}
 
@@ -148,43 +147,23 @@ func (c *MessageSessionClient) getMessage(ctx context.Context, lastMessageID int
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode == http.StatusAccepted {
+	switch resp.StatusCode {
+	case http.StatusAccepted:
 		return nil, nil
-	}
 
-	if resp.StatusCode != http.StatusOK {
-		if resp.StatusCode != http.StatusUnauthorized {
-			return nil, ParseActionsErrorFromResponse(resp)
-		}
-
-		body, err := io.ReadAll(resp.Body)
-		body = trimByteOrderMark(body)
+	case http.StatusOK:
+		message, err := parseRunnerScaleSetMessageResponse(resp.Body)
 		if err != nil {
-			return nil, &ActionsError{
-				ActivityID: resp.Header.Get(headerActionsActivityID),
-				StatusCode: resp.StatusCode,
-				Err:        err,
-			}
+			return nil, newRequestResponseError(req, resp, fmt.Errorf("failed to parse message response: %w", err))
 		}
-		return nil, &ActionsError{
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			StatusCode: resp.StatusCode,
-			Err: &messageQueueTokenExpiredError{
-				message: string(body),
-			},
-		}
-	}
+		return message, nil
 
-	message, err := parseRunnerScaleSetMessageResponse(resp.Body)
-	if err != nil {
-		return nil, &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
-	}
+	case http.StatusUnauthorized:
+		return nil, newRequestResponseError(req, resp, MessageQueueTokenExpiredError)
 
-	return message, nil
+	default:
+		return nil, newRequestResponseError(req, resp, fmt.Errorf("unexpected status code %s", resp.Status))
+	}
 }
 
 // DeleteMessage deletes a message from the runner scale set message queue.
@@ -199,8 +178,7 @@ func (c *MessageSessionClient) DeleteMessage(ctx context.Context, messageID int)
 		return nil
 	}
 
-	expiredError := &ActionsError{}
-	if !errors.As(err, &expiredError) || !expiredError.IsMessageQueueTokenExpired() {
+	if !errors.Is(err, MessageQueueTokenExpiredError) {
 		return fmt.Errorf("failed to delete message: %w", err)
 	}
 
@@ -239,25 +217,10 @@ func (c *MessageSessionClient) deleteMessage(ctx context.Context, messageID int)
 	}
 
 	if resp.StatusCode != http.StatusUnauthorized {
-		return ParseActionsErrorFromResponse(resp)
+		return newRequestResponseError(req, resp, fmt.Errorf("unexpected status code %s", resp.Status))
 	}
 
-	body, err := io.ReadAll(resp.Body)
-	body = trimByteOrderMark(body)
-	if err != nil {
-		return &ActionsError{
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			StatusCode: resp.StatusCode,
-			Err:        err,
-		}
-	}
-	return &ActionsError{
-		ActivityID: resp.Header.Get(headerActionsActivityID),
-		StatusCode: resp.StatusCode,
-		Err: &messageQueueTokenExpiredError{
-			message: string(body),
-		},
-	}
+	return newRequestResponseError(req, resp, MessageQueueTokenExpiredError)
 }
 
 func (c *MessageSessionClient) Session() RunnerScaleSetSession {
@@ -284,39 +247,17 @@ func (c *MessageSessionClient) doSessionRequest(ctx context.Context, method, pat
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode == expectedResponseStatusCode {
-		if responseUnmarshalTarget == nil {
-			return nil
-		}
-
-		if err := json.NewDecoder(resp.Body).Decode(responseUnmarshalTarget); err != nil {
-			return &ActionsError{
-				StatusCode: resp.StatusCode,
-				ActivityID: resp.Header.Get(headerActionsActivityID),
-				Err:        err,
-			}
-		}
+	if resp.StatusCode != expectedResponseStatusCode {
+		return newRequestResponseError(req, resp, fmt.Errorf("unexpected status code %s", resp.Status))
+	}
 
+	if responseUnmarshalTarget == nil {
 		return nil
 	}
 
-	if resp.StatusCode >= 400 && resp.StatusCode < 500 {
-		return ParseActionsErrorFromResponse(resp)
+	if err := json.NewDecoder(resp.Body).Decode(responseUnmarshalTarget); err != nil {
+		return newRequestResponseError(req, resp, fmt.Errorf("failed to unmarshal response body: %w", err))
 	}
 
-	body, err := io.ReadAll(resp.Body)
-	body = trimByteOrderMark(body)
-	if err != nil {
-		return &ActionsError{
-			StatusCode: resp.StatusCode,
-			ActivityID: resp.Header.Get(headerActionsActivityID),
-			Err:        err,
-		}
-	}
-
-	return fmt.Errorf("unexpected status code: %w", &ActionsError{
-		StatusCode: resp.StatusCode,
-		ActivityID: resp.Header.Get(headerActionsActivityID),
-		Err:        errors.New(string(body)),
-	})
+	return nil
 }

session_client_test.go

@@ -62,7 +62,7 @@ func TestCreateMessageSession(t *testing.T) {
 		assert.Equal(t, want, session)
 	})
 
-	t.Run("CreateMessageSession unmarshals errors into ActionsError", func(t *testing.T) {
+	t.Run("CreateMessageSession includes actions exception details", func(t *testing.T) {
 		owner := "foo"
 		runnerScaleSet := RunnerScaleSet{
 			ID:            1,
@@ -71,15 +71,6 @@ func TestCreateMessageSession(t *testing.T) {
 			RunnerSetting: RunnerSetting{},
 		}
 
-		want := &ActionsError{
-			ActivityID: exampleRequestID,
-			StatusCode: http.StatusBadRequest,
-			Err: &actionsExceptionError{
-				ExceptionName: "CSharpExceptionNameHere",
-				Message:       "could not do something",
-			},
-		}
-
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 			w.Header().Set("Content-Type", "application/json")
 			w.Header().Set(headerActionsActivityID, exampleRequestID)
@@ -97,11 +88,14 @@ func TestCreateMessageSession(t *testing.T) {
 
 		sessionClient, err := client.MessageSessionClient(context.Background(), runnerScaleSet.ID, owner)
 		assert.Nil(t, sessionClient)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "status=\"400 Bad Request\"")
+		assert.Contains(t, err.Error(), "activity_id=\""+exampleRequestID+"\"")
 
-		errorTypeForComparison := &ActionsError{}
-		assert.ErrorAs(t, err, &errorTypeForComparison)
-
-		assert.Equal(t, want, errorTypeForComparison)
+		var ex actionsExceptionError
+		assert.True(t, errors.As(err, &ex))
+		assert.Equal(t, "CSharpExceptionNameHere", ex.ExceptionName)
+		assert.Equal(t, "could not do something", ex.Message)
 	})
 
 	t.Run("CreateMessageSession call is retried the correct amount of times", func(t *testing.T) {
@@ -285,10 +279,7 @@ func TestGetMessage(t *testing.T) {
 
 		msg, err := sessionClient.GetMessage(ctx, 0, 10)
 		assert.Nil(t, msg)
-
-		var expectedErr *ActionsError
-		require.ErrorAs(t, err, &expectedErr)
-		assert.True(t, expectedErr.IsMessageQueueTokenExpired(), "expected error to be of type MessageQueueTokenExpiredError but got: %v", err)
+		assert.ErrorIs(t, err, MessageQueueTokenExpiredError, "expected error to be MessageQueueTokenExpiredError but got: %v", err)
 	})
 
 	t.Run("Message token refreshed", func(t *testing.T) {
@@ -345,10 +336,6 @@ func TestGetMessage(t *testing.T) {
 	})
 
 	t.Run("Status code not found", func(t *testing.T) {
-		want := ActionsError{
-			Err:        errors.New("unknown exception"),
-			StatusCode: 404,
-		}
 		var handleSessionRequest http.HandlerFunc
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if strings.HasSuffix(r.URL.Path, "sessions") {
@@ -371,21 +358,22 @@ func TestGetMessage(t *testing.T) {
 
 		msg, err := sessionClient.GetMessage(ctx, 0, 10)
 		assert.Nil(t, msg)
-		var got *ActionsError
-		require.ErrorAs(t, err, &got)
-		assert.Equal(t, want.StatusCode, got.StatusCode)
-		assert.Equal(t, want.Err.Error(), got.Err.Error())
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "status=\"404 Not Found\"")
+		assert.Contains(t, err.Error(), "unknown error")
 	})
 
 	t.Run("Error when Content-Type is text/plain", func(t *testing.T) {
+		plainBody := "example plain text error"
 		var handleSessionRequest http.HandlerFunc
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if strings.HasSuffix(r.URL.Path, "sessions") {
 				handleSessionRequest(w, r)
 				return
 			}
-			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(plainBody))
 		}))
 		handleSessionRequest = newTestSessionRequestHandler(t, server.testRunnerScaleSetSession())
 
@@ -402,9 +390,12 @@ func TestGetMessage(t *testing.T) {
 		msg, err := sessionClient.GetMessage(ctx, 0, 10)
 		assert.Nil(t, msg)
 		assert.NotNil(t, err)
+		assert.Contains(t, err.Error(), "status=\"400 Bad Request\"")
+		assert.Contains(t, err.Error(), plainBody)
 	})
 
 	t.Run("Capacity error handling", func(t *testing.T) {
+		plainBody := "capacity error"
 		var handleSessionRequest http.HandlerFunc
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if strings.HasSuffix(r.URL.Path, "sessions") {
@@ -415,9 +406,9 @@ func TestGetMessage(t *testing.T) {
 			c, err := strconv.Atoi(hc)
 			require.NoError(t, err)
 			assert.GreaterOrEqual(t, c, 0)
-
-			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(plainBody))
 		}))
 		handleSessionRequest = newTestSessionRequestHandler(t, server.testRunnerScaleSetSession())
 
@@ -434,9 +425,8 @@ func TestGetMessage(t *testing.T) {
 		msg, err := sessionClient.GetMessage(ctx, 0, 0)
 		assert.Nil(t, msg)
 		assert.Error(t, err)
-		var expectedErr *ActionsError
-		assert.ErrorAs(t, err, &expectedErr)
-		assert.Equal(t, http.StatusBadRequest, expectedErr.StatusCode)
+		assert.Contains(t, err.Error(), "status=\"400 Bad Request\"")
+		assert.Contains(t, err.Error(), plainBody)
 	})
 }
 
@@ -506,9 +496,7 @@ func TestDeleteMessage(t *testing.T) {
 
 		err = sessionClient.DeleteMessage(ctx, 0)
 		require.NotNil(t, err)
-		var expectedErr *ActionsError
-		require.ErrorAs(t, err, &expectedErr)
-		assert.True(t, expectedErr.IsMessageQueueTokenExpired())
+		assert.ErrorIs(t, err, MessageQueueTokenExpiredError, "expected error to be MessageQueueTokenExpiredError but got: %v", err)
 	})
 
 	t.Run("message token refreshed", func(t *testing.T) {
@@ -563,14 +551,16 @@ func TestDeleteMessage(t *testing.T) {
 	})
 
 	t.Run("Error when Content-Type is text/plain", func(t *testing.T) {
+		plainBody := "example plain text error"
 		var handleSessionRequest http.HandlerFunc
 		server := newActionsServer(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if strings.HasSuffix(r.URL.Path, "sessions") {
 				handleSessionRequest(w, r)
 				return
 			}
-			w.WriteHeader(http.StatusBadRequest)
 			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusBadRequest)
+			w.Write([]byte(plainBody))
 		}))
 		handleSessionRequest = newTestSessionRequestHandler(t, server.testRunnerScaleSetSession())
 
@@ -586,10 +576,9 @@ func TestDeleteMessage(t *testing.T) {
 
 		err = sessionClient.DeleteMessage(ctx, runnerScaleSetMessage.MessageID)
 		require.NotNil(t, err)
-		var expectedErr *ActionsError
-		assert.True(t, errors.As(err, &expectedErr))
-	},
-	)
+		assert.Contains(t, err.Error(), "status=\"400 Bad Request\"")
+		assert.Contains(t, err.Error(), plainBody)
+	})
 
 	t.Run("Default retries on server error", func(t *testing.T) {
 		actualRetry := 0
@@ -656,7 +645,7 @@ func TestDeleteMessage(t *testing.T) {
 		require.NoError(t, err)
 
 		err = sessionClient.DeleteMessage(ctx, runnerScaleSetMessage.MessageID+1)
-		var expectedErr *ActionsError
-		require.True(t, errors.As(err, &expectedErr))
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "unexpected status code")
 	})
 }