feat: add Nginx to Caddy migration toolkit with scripts and usage guide

setup/nginx-to-caddy/CUTOVER_CHECKLIST.md

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+# Cutover Checklist
+
+## Pre-cutover
+- [ ] `nginx -T` snapshot captured (`output/nginx-full.conf`)
+- [ ] Generated Caddyfile reviewed
+- [ ] `conversion-warnings.txt` reviewed and resolved for canary site
+- [ ] `validate_caddy.sh` passes
+- [ ] DNS TTL lowered for canary domain
+
+## Canary
+- [ ] One subdomain switched to Caddy
+- [ ] HTTPS cert valid
+- [ ] UI and API calls work
+- [ ] Websocket/live components work
+- [ ] Access/error logs clean
+
+## Full rollout
+- [ ] Remaining subdomains switched in batches
+- [ ] Monitor 24h
+- [ ] Keep Nginx rollback config archived
+
+## Rollback trigger
+- [ ] TLS failures
+- [ ] High 4xx/5xx
+- [ ] Broken websockets/realtime components
+- [ ] Unexpected redirects or auth loops

setup/nginx-to-caddy/README.md

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+# Nginx to Caddy Toolkit
+
+Purpose: inventory an existing Nginx reverse-proxy setup and generate a first-pass Caddyfile for simple host/path proxying.
+
+This module is intentionally conservative:
+- it auto-converts common/basic patterns
+- it flags complex directives for manual review
+- it never edits live Nginx config
+
+## Scripts
+
+- `extract_nginx_inventory.sh`
+  - SSH into a host and collect `nginx -T`, `/etc/nginx` tarball, and a quick inventory summary.
+- `nginx_to_caddy.sh`
+  - Convert basic Nginx server blocks into a generated Caddyfile.
+- `validate_caddy.sh`
+  - Run `caddy fmt`, `caddy adapt`, and `caddy validate` on the generated Caddyfile.
+
+## Quick Start
+
+```bash
+cd setup/nginx-to-caddy
+
+./extract_nginx_inventory.sh --host=<host> --user=<user> --port=22 --yes
+./nginx_to_caddy.sh --input=./output/nginx-full.conf --output=./output/Caddyfile.generated --tls-mode=cloudflare --yes
+./validate_caddy.sh --config=./output/Caddyfile.generated --docker
+```
+
+## Conversion Scope
+
+Automatically handled:
+- `server_name`
+- `listen` (80/443 hints)
+- `ssl_certificate`, `ssl_certificate_key`
+- `return 301/302 ...`
+- `location` + `proxy_pass` (simple prefix or exact path)
+
+Manual follow-up required for:
+- regex locations (`~`, `~*`)
+- `rewrite`, `try_files`, `if`, `map`
+- FastCGI/uWSGI/SCGI/gRPC backends
+- auth subrequests, Lua, or advanced caching directives
+
+See `USAGE_GUIDE.md` for a safe migration workflow.

setup/nginx-to-caddy/USAGE_GUIDE.md

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+# Usage Guide: Nginx to Caddy Migration
+
+This guide helps you migrate safely without big-bang risk.
+
+## 1) Collect Nginx inventory
+
+Run from your admin machine:
+
+```bash
+cd setup/nginx-to-caddy
+./extract_nginx_inventory.sh --host=<nginx-host-ip> --user=<ssh-user> --port=22 --yes
+```
+
+You will get:
+- `output/nginx-full.conf`
+- `output/etc-nginx.tar.gz`
+- `output/inventory-summary.txt`
+
+## 2) Generate initial Caddyfile
+
+For Cloudflare DNS-01 flow:
+
+```bash
+./nginx_to_caddy.sh \
+  --input=./output/nginx-full.conf \
+  --output=./output/Caddyfile.generated \
+  --warnings=./output/conversion-warnings.txt \
+  --tls-mode=cloudflare \
+  --yes
+```
+
+Review warnings:
+
+```bash
+cat ./output/conversion-warnings.txt
+```
+
+If warnings include rewrite/regex/auth directives, expect manual edits.
+
+## 3) Validate generated config
+
+If `caddy` is not installed locally, use Docker:
+
+```bash
+./validate_caddy.sh --config=./output/Caddyfile.generated --docker
+```
+
+If local `caddy` is installed:
+
+```bash
+./validate_caddy.sh --config=./output/Caddyfile.generated
+```
+
+## 4) Canary migration (recommended)
+
+Migrate one low-risk subdomain first:
+1. Copy only one site block from generated Caddyfile to your live Caddy config.
+2. Point only that DNS record to Caddy target.
+3. Verify:
+   - TLS cert valid
+   - page loads
+   - API/websocket calls work
+4. Keep Nginx serving all other subdomains.
+
+## 5) Full migration after canary success
+
+When the canary is stable:
+1. Add remaining site blocks.
+2. Move DNS entries in batches.
+3. Keep Nginx config snapshots for rollback.
+4. Decommission Nginx only after monitoring period.
+
+## 6) Rollback plan
+
+If a site fails after cutover:
+1. Repoint affected DNS entry back to Nginx endpoint.
+2. Restore previous Nginx server block.
+3. Investigate conversion warnings for that block.
+
+## 7) Domain/TLS note for your current setup
+
+You confirmed the domain is `privacyindesign.com`.
+
+If you use `TLS_MODE=cloudflare` with Caddy, ensure:
+- Caddy site labels use `*.privacyindesign.com` or specific subdomains under it.
+- Cloudflare token has DNS edit on the same zone.
+- DNS records point to the Caddy ingress path you intend (direct or via edge proxy).
+
+## 8) Suggested next step for Phase 8
+
+Given your current repo config:
+- keep Phase 8 Caddy focused on `source.privacyindesign.com`
+- migrate broader Nginx estate separately with this toolkit
+
+That keeps Gitea cutover small and lowers blast radius.

setup/nginx-to-caddy/extract_nginx_inventory.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=./lib.sh
+source "$SCRIPT_DIR/lib.sh"
+
+REMOTE_HOST=""
+REMOTE_USER=""
+REMOTE_PORT="22"
+OUT_DIR="$SCRIPT_DIR/output"
+AUTO_YES=false
+USE_SUDO=true
+
+usage() {
+  cat <<USAGE
+Usage: $(basename "$0") --host=IP --user=NAME [options]
+
+Collect Nginx config inventory from a remote host for conversion planning.
+
+Options:
+  --host=IP            Remote host/IP (required)
+  --user=NAME          SSH username (required)
+  --port=PORT          SSH port (default: 22)
+  --out-dir=PATH       Output directory (default: setup/nginx-to-caddy/output)
+  --no-sudo            Use nginx commands without sudo
+  --yes, -y            Skip confirmation prompt
+  --help, -h           Show help
+
+Outputs:
+  nginx-version.txt
+  nginx-full.conf            (nginx -T combined output)
+  etc-nginx.tar.gz           (/etc/nginx snapshot tarball)
+  inventory-summary.txt      (basic discovered domains/proxy targets)
+USAGE
+}
+
+for arg in "$@"; do
+  case "$arg" in
+    --host=*) REMOTE_HOST="${arg#*=}" ;;
+    --user=*) REMOTE_USER="${arg#*=}" ;;
+    --port=*) REMOTE_PORT="${arg#*=}" ;;
+    --out-dir=*) OUT_DIR="${arg#*=}" ;;
+    --no-sudo) USE_SUDO=false ;;
+    --yes|-y) AUTO_YES=true ;;
+    --help|-h) usage; exit 0 ;;
+    *) log_error "Unknown argument: $arg"; usage; exit 1 ;;
+  esac
+done
+
+require_cmd ssh tar awk sed grep
+
+if [[ -z "$REMOTE_HOST" || -z "$REMOTE_USER" ]]; then
+  log_error "--host and --user are required"
+  usage
+  exit 1
+fi
+
+if ! confirm_action "Collect nginx config from ${REMOTE_USER}@${REMOTE_HOST}?" "$AUTO_YES"; then
+  log_info "Cancelled"
+  exit 0
+fi
+
+mkdir -p "$OUT_DIR"
+
+sudo_prefix=""
+if [[ "$USE_SUDO" == "true" ]]; then
+  sudo_prefix="sudo "
+fi
+
+ssh_target="${REMOTE_USER}@${REMOTE_HOST}"
+ssh_opts=( -p "$REMOTE_PORT" -o BatchMode=yes -o StrictHostKeyChecking=accept-new )
+
+log_info "Checking SSH connectivity..."
+ssh "${ssh_opts[@]}" "$ssh_target" "echo connected" >/dev/null
+
+log_info "Capturing nginx version and build info..."
+ssh "${ssh_opts[@]}" "$ssh_target" "${sudo_prefix}nginx -V 2>&1" > "${OUT_DIR}/nginx-version.txt"
+
+log_info "Capturing full rendered nginx config (nginx -T)..."
+ssh "${ssh_opts[@]}" "$ssh_target" "${sudo_prefix}nginx -T 2>&1" > "${OUT_DIR}/nginx-full.conf"
+
+log_info "Capturing /etc/nginx snapshot..."
+ssh "${ssh_opts[@]}" "$ssh_target" "${sudo_prefix}tar -C / -czf - etc/nginx" > "${OUT_DIR}/etc-nginx.tar.gz"
+
+log_info "Building inventory summary..."
+{
+  echo "Inventory generated: $(date -u +%Y-%m-%dT%H:%M:%SZ)"
+  echo
+  echo "Server names:"
+  awk '
+    /^[[:space:]]*server_name[[:space:]]+/ {
+      line=$0
+      sub(/^[[:space:]]*server_name[[:space:]]+/, "", line)
+      sub(/[[:space:]]*;[[:space:]]*$/, "", line)
+      gsub(/[[:space:]]+/, " ", line)
+      print "  - " line
+    }
+  ' "${OUT_DIR}/nginx-full.conf" | sort -u
+  echo
+  echo "Proxy targets:"
+  awk '
+    /^[[:space:]]*proxy_pass[[:space:]]+/ {
+      line=$0
+      sub(/^[[:space:]]*proxy_pass[[:space:]]+/, "", line)
+      sub(/[[:space:]]*;[[:space:]]*$/, "", line)
+      print "  - " line
+    }
+  ' "${OUT_DIR}/nginx-full.conf" | sort -u
+} > "${OUT_DIR}/inventory-summary.txt"
+
+log_success "Nginx inventory collected in: ${OUT_DIR}"
+log_info "Next: run nginx_to_caddy.sh --input=${OUT_DIR}/nginx-full.conf"

setup/nginx-to-caddy/lib.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+if [[ -t 2 ]]; then
+  _C_RESET='\033[0m'
+  _C_RED='\033[0;31m'
+  _C_GREEN='\033[0;32m'
+  _C_YELLOW='\033[0;33m'
+  _C_BLUE='\033[0;34m'
+else
+  _C_RESET='' _C_RED='' _C_GREEN='' _C_YELLOW='' _C_BLUE=''
+fi
+
+log_info() {
+  printf '%b[INFO]%b %s\n' "$_C_BLUE" "$_C_RESET" "$*" >&2
+}
+
+log_warn() {
+  printf '%b[WARN]%b %s\n' "$_C_YELLOW" "$_C_RESET" "$*" >&2
+}
+
+log_error() {
+  printf '%b[ERROR]%b %s\n' "$_C_RED" "$_C_RESET" "$*" >&2
+}
+
+log_success() {
+  printf '%b[OK]%b %s\n' "$_C_GREEN" "$_C_RESET" "$*" >&2
+}
+
+require_cmd() {
+  local cmd
+  for cmd in "$@"; do
+    if ! command -v "$cmd" >/dev/null 2>&1; then
+      log_error "Required command not found: $cmd"
+      return 1
+    fi
+  done
+}
+
+confirm_action() {
+  local prompt="${1:-Continue?}"
+  local auto_yes="${2:-false}"
+
+  if [[ "$auto_yes" == "true" ]]; then
+    return 0
+  fi
+
+  printf '%s [y/N] ' "$prompt"
+  read -r reply
+  [[ "$reply" =~ ^[Yy]$ ]]
+}

setup/nginx-to-caddy/nginx_to_caddy.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=./lib.sh
+source "$SCRIPT_DIR/lib.sh"
+
+INPUT_FILE=""
+OUTPUT_FILE="$SCRIPT_DIR/output/Caddyfile.generated"
+WARNINGS_FILE="$SCRIPT_DIR/output/conversion-warnings.txt"
+TLS_MODE="auto"
+STRICT=false
+AUTO_YES=false
+
+usage() {
+  cat <<USAGE
+Usage: $(basename "$0") --input=nginx-full.conf [options]
+
+Convert basic Nginx server/location/proxy_pass blocks to a Caddyfile.
+
+Options:
+  --input=PATH          Input config (usually nginx -T output)
+  --output=PATH         Output Caddyfile (default: setup/nginx-to-caddy/output/Caddyfile.generated)
+  --warnings=PATH       Warning report path (default: setup/nginx-to-caddy/output/conversion-warnings.txt)
+  --tls-mode=MODE       TLS strategy: auto|cloudflare|existing (default: auto)
+  --strict              Exit non-zero if any unsupported directives are found
+  --yes, -y             Skip confirmation prompt
+  --help, -h            Show help
+
+Coverage:
+  - server_name
+  - listen (80/443 detection)
+  - ssl_certificate / ssl_certificate_key
+  - return 301/302 redirects
+  - location + proxy_pass (prefix and exact paths)
+
+Not automatically converted:
+  - regex locations (~, ~*)
+  - fastcgi/uwsgi/scgi/grpc
+  - try_files/rewrite/map/if/auth_request/lua
+USAGE
+}
+
+for arg in "$@"; do
+  case "$arg" in
+    --input=*) INPUT_FILE="${arg#*=}" ;;
+    --output=*) OUTPUT_FILE="${arg#*=}" ;;
+    --warnings=*) WARNINGS_FILE="${arg#*=}" ;;
+    --tls-mode=*) TLS_MODE="${arg#*=}" ;;
+    --strict) STRICT=true ;;
+    --yes|-y) AUTO_YES=true ;;
+    --help|-h) usage; exit 0 ;;
+    *) log_error "Unknown argument: $arg"; usage; exit 1 ;;
+  esac
+done
+
+require_cmd awk sed grep sort mktemp
+
+if [[ -z "$INPUT_FILE" ]]; then
+  log_error "--input is required"
+  usage
+  exit 1
+fi
+
+if [[ ! -f "$INPUT_FILE" ]]; then
+  log_error "Input file not found: $INPUT_FILE"
+  exit 1
+fi
+
+case "$TLS_MODE" in
+  auto|cloudflare|existing) ;;
+  *) log_error "Invalid --tls-mode '$TLS_MODE' (use: auto|cloudflare|existing)"; exit 1 ;;
+esac
+
+mkdir -p "$(dirname "$OUTPUT_FILE")" "$(dirname "$WARNINGS_FILE")"
+: > "$WARNINGS_FILE"
+
+warn() {
+  local msg="$1"
+  printf '%s\n' "$msg" >> "$WARNINGS_FILE"
+  log_warn "$msg"
+}
+
+join_by_comma() {
+  local first=true
+  local out=""
+  local item
+  for item in "$@"; do
+    if [[ "$first" == true ]]; then
+      out="$item"
+      first=false
+    else
+      out+=", $item"
+    fi
+  done
+  printf '%s' "$out"
+}
+
+normalize_redirect_target() {
+  local target="$1"
+  target="$(printf '%s' "$target" | sed \
+    -e 's/\$server_name/{host}/g' \
+    -e 's/\$http_host/{host}/g' \
+    -e 's/\$host/{host}/g' \
+    -e 's/\$request_uri/{uri}/g' \
+    -e 's/\$uri/{uri}/g' \
+    -e 's/\$scheme/{scheme}/g')"
+  printf '%s' "$target"
+}
+
+extract_upstream_targets() {
+  local src="$1"
+
+  awk '
+    function clean_comments(s) {
+      sub(/[[:space:]]*#.*/, "", s)
+      return s
+    }
+    function trim(s) {
+      sub(/^[[:space:]]+/, "", s)
+      sub(/[[:space:]]+$/, "", s)
+      return s
+    }
+    function brace_delta(s, tmp, opens, closes) {
+      tmp = s
+      opens = gsub(/\{/, "{", tmp)
+      closes = gsub(/\}/, "}", tmp)
+      return opens - closes
+    }
+
+    BEGIN {
+      in_upstream = 0
+      depth = 0
+      upstream_name = ""
+      targets = ""
+    }
+
+    {
+      raw = $0
+      line = clean_comments(raw)
+
+      if (!in_upstream) {
+        if (line ~ /^[[:space:]]*upstream[[:space:]]+[A-Za-z0-9_.-]+[[:space:]]*\{[[:space:]]*$/) {
+          tmp = line
+          sub(/^[[:space:]]*upstream[[:space:]]+/, "", tmp)
+          sub(/[[:space:]]*\{[[:space:]]*$/, "", tmp)
+          upstream_name = trim(tmp)
+          in_upstream = 1
+          depth = 1
+          targets = ""
+          next
+        }
+      } else {
+        if (line ~ /^[[:space:]]*server[[:space:]]+/) {
+          tmp = line
+          sub(/^[[:space:]]*server[[:space:]]+/, "", tmp)
+          sub(/[[:space:]]*;[[:space:]]*$/, "", tmp)
+          tmp = trim(tmp)
+          if (tmp != "") {
+            if (targets == "") {
+              targets = tmp
+            } else {
+              targets = targets "," tmp
+            }
+          }
+        }
+
+        depth += brace_delta(line)
+        if (depth <= 0) {
+          if (upstream_name != "" && targets != "") {
+            print upstream_name "|" targets
+          }
+          in_upstream = 0
+          depth = 0
+          upstream_name = ""
+          targets = ""
+        }
+      }
+    }
+  ' "$src"
+}
+
+UPSTREAM_NAMES=()
+UPSTREAM_TARGETS=()
+
+load_upstream_map() {
+  local line name targets first_target
+  while IFS= read -r line; do
+    [[ -z "$line" ]] && continue
+    IFS='|' read -r name targets <<< "$line"
+    [[ -z "$name" || -z "$targets" ]] && continue
+    first_target="${targets%%,*}"
+
+    UPSTREAM_NAMES+=("$name")
+    UPSTREAM_TARGETS+=("$first_target")
+
+    if [[ "$targets" == *,* ]]; then
+      warn "upstream '${name}' has multiple servers (${targets}); using first target '${first_target}'"
+      unsupported_count=$((unsupported_count + 1))
+    fi
+  done < <(extract_upstream_targets "$INPUT_FILE")
+}
+
+lookup_upstream_target() {
+  local name="$1"
+  local i
+  for i in "${!UPSTREAM_NAMES[@]}"; do
+    if [[ "${UPSTREAM_NAMES[$i]}" == "$name" ]]; then
+      printf '%s' "${UPSTREAM_TARGETS[$i]}"
+      return 0
+    fi
+  done
+  return 1
+}
+
+resolve_proxy_target() {
+  local proxy_target="$1"
+  local block_id="$2"
+  local scheme host port path mapped
+
+  if [[ "$proxy_target" =~ ^(https?)://([^/:]+)(:[0-9]+)?(.*)$ ]]; then
+    scheme="${BASH_REMATCH[1]}"
+    host="${BASH_REMATCH[2]}"
+    port="${BASH_REMATCH[3]}"
+    path="${BASH_REMATCH[4]}"
+
+    if mapped="$(lookup_upstream_target "$host")"; then
+      printf '%s://%s%s' "$scheme" "$mapped" "$path"
+      return 0
+    fi
+
+    # If host has no dot and no upstream definition, call it out.
+    if [[ "$host" != *.* ]]; then
+      warn "${block_id}: upstream '${host}' not found; leaving proxy target as '${proxy_target}'"
+      unsupported_count=$((unsupported_count + 1))
+    fi
+  fi
+
+  printf '%s' "$proxy_target"
+}
+
+extract_server_blocks() {
+  local src="$1"
+  local out_dir="$2"
+
+  awk -v out_dir="$out_dir" '
+    function clean_comments(s) {
+      sub(/[[:space:]]*#.*/, "", s)
+      return s
+    }
+    function brace_delta(s, tmp, opens, closes) {
+      tmp = s
+      opens = gsub(/\{/, "{", tmp)
+      closes = gsub(/\}/, "}", tmp)
+      return opens - closes
+    }
+
+    BEGIN {
+      in_server = 0
+      depth = 0
+      idx = 0
+      file = ""
+    }
+
+    {
+      raw = $0
+      line = clean_comments(raw)
+
+      if (!in_server) {
+        if (line ~ /^[[:space:]]*server[[:space:]]*\{[[:space:]]*$/) {
+          in_server = 1
+          depth = 0
+          idx += 1
+          file = sprintf("%s/server_%03d.conf", out_dir, idx)
+        }
+      }
+
+      if (in_server) {
+        print raw >> file
+        depth += brace_delta(line)
+
+        if (depth <= 0) {
+          close(file)
+          in_server = 0
+          depth = 0
+          file = ""
+        }
+      }
+    }
+
+    END {
+      print idx
+    }
+  ' "$src"
+}
+
+if ! confirm_action "Convert ${INPUT_FILE} to Caddyfile now?" "$AUTO_YES"; then
+  log_info "Cancelled"
+  exit 0
+fi
+
+tmp_dir="$(mktemp -d)"
+trap 'rm -rf "$tmp_dir"' EXIT
+
+server_count="$(extract_server_blocks "$INPUT_FILE" "$tmp_dir")"
+if [[ -z "$server_count" || "$server_count" -eq 0 ]]; then
+  log_error "No Nginx server blocks found in $INPUT_FILE"
+  exit 1
+fi
+
+{
+  echo "# ---------------------------------------------------------------------------"
+  echo "# Generated by setup/nginx-to-caddy/nginx_to_caddy.sh"
+  echo "# Source: $INPUT_FILE"
+  echo "# Generated at: $(date -u +%Y-%m-%dT%H:%M:%SZ)"
+  echo "# ---------------------------------------------------------------------------"
+  echo
+} > "$OUTPUT_FILE"
+
+converted_blocks=0
+unsupported_count=0
+load_upstream_map
+
+for block in "$tmp_dir"/server_*.conf; do
+  [[ -f "$block" ]] || continue
+  block_id="$(basename "$block" .conf)"
+
+  # Collect server names
+  names=()
+  while IFS= read -r line; do
+    [[ -z "$line" ]] && continue
+    for token in $line; do
+      [[ "$token" == "_" ]] && continue
+      seen=false
+      for existing in "${names[@]:-}"; do
+        if [[ "$existing" == "$token" ]]; then
+          seen=true
+          break
+        fi
+      done
+      if [[ "$seen" == false ]]; then
+        names+=("$token")
+      fi
+    done
+  done < <(
+    awk '
+      /^[[:space:]]*server_name[[:space:]]+/ {
+        line=$0
+        sub(/^[[:space:]]*server_name[[:space:]]+/, "", line)
+        sub(/[[:space:]]*;[[:space:]]*$/, "", line)
+        gsub(/[[:space:]]+/, " ", line)
+        print line
+      }
+    ' "$block"
+  )
+
+  if [[ ${#names[@]} -eq 0 ]]; then
+    warn "${block_id}: no server_name found; skipping block"
+    unsupported_count=$((unsupported_count + 1))
+    continue
+  fi
+
+  # Detect listen hints
+  listen_443=false
+  listen_80=false
+  if grep -Eq '^[[:space:]]*listen[[:space:]][^;]*(443|ssl)' "$block"; then
+    listen_443=true
+  fi
+  if grep -Eq '^[[:space:]]*listen[[:space:]][^;]*80([^0-9]|$)' "$block"; then
+    listen_80=true
+  fi
+
+  ssl_cert="$(awk '/^[[:space:]]*ssl_certificate[[:space:]]+/ { line=$0; sub(/^[[:space:]]*ssl_certificate[[:space:]]+/, "", line); sub(/[[:space:]]*;[[:space:]]*$/, "", line); print line; exit }' "$block")"
+  ssl_key="$(awk '/^[[:space:]]*ssl_certificate_key[[:space:]]+/ { line=$0; sub(/^[[:space:]]*ssl_certificate_key[[:space:]]+/, "", line); sub(/[[:space:]]*;[[:space:]]*$/, "", line); print line; exit }' "$block")"
+
+  redirect_code=""
+  redirect_target=""
+  redirect_line="$(awk '/^[[:space:]]*return[[:space:]]+30[12][[:space:]]+/ { line=$0; sub(/^[[:space:]]*/, "", line); sub(/[[:space:]]*;[[:space:]]*$/, "", line); print line; exit }' "$block")"
+  if [[ -n "$redirect_line" ]]; then
+    if [[ "$redirect_line" =~ ^return[[:space:]]+([0-9]{3})[[:space:]]+(.+)$ ]]; then
+      redirect_code="${BASH_REMATCH[1]}"
+      redirect_target="$(normalize_redirect_target "${BASH_REMATCH[2]}")"
+    fi
+  fi
+
+  map_lines="$(awk '
+    function trim(s) {
+      sub(/^[[:space:]]+/, "", s)
+      sub(/[[:space:]]+$/, "", s)
+      return s
+    }
+    function clean_comments(s) {
+      sub(/[[:space:]]*#.*/, "", s)
+      return s
+    }
+    function brace_delta(s, t, o, c) {
+      t=s
+      o=gsub(/\{/, "{", t)
+      c=gsub(/\}/, "}", t)
+      return o-c
+    }
+
+    BEGIN {
+      in_loc=0
+      depth=0
+      loc_expr=""
+      proxy=""
+      insecure_tls=0
+    }
+
+    {
+      raw=$0
+      line=clean_comments(raw)
+
+      if (!in_loc) {
+        if (line ~ /^[[:space:]]*location[[:space:]]+/ && line ~ /\{[[:space:]]*$/) {
+          tmp=line
+          sub(/^[[:space:]]*location[[:space:]]+/, "", tmp)
+          sub(/[[:space:]]*\{[[:space:]]*$/, "", tmp)
+          in_loc=1
+          depth=1
+          loc_expr=trim(tmp)
+          proxy=""
+          insecure_tls=0
+          next
+        }
+      } else {
+        if (line ~ /^[[:space:]]*proxy_pass[[:space:]]+/) {
+          tmp=line
+          sub(/^[[:space:]]*proxy_pass[[:space:]]+/, "", tmp)
+          sub(/[[:space:]]*;[[:space:]]*$/, "", tmp)
+          proxy=trim(tmp)
+        }
+        if (line ~ /^[[:space:]]*proxy_ssl_verify[[:space:]]+off[[:space:]]*;[[:space:]]*$/) {
+          insecure_tls=1
+        }
+
+        depth += brace_delta(line)
+        if (depth <= 0) {
+          if (proxy != "") {
+            print loc_expr "|" proxy "|" insecure_tls
+          }
+          in_loc=0
+          depth=0
+          loc_expr=""
+          proxy=""
+          insecure_tls=0
+        }
+      }
+    }
+  ' "$block")"
+
+  if grep -nE '^[[:space:]]*(if|map|rewrite|try_files|fastcgi_pass|uwsgi_pass|scgi_pass|grpc_pass|auth_request)\b' "$block" >/dev/null; then
+    while IFS= read -r line; do
+      warn "${block_id}: unsupported directive -> ${line}"
+      unsupported_count=$((unsupported_count + 1))
+    done < <(grep -nE '^[[:space:]]*(if|map|rewrite|try_files|fastcgi_pass|uwsgi_pass|scgi_pass|grpc_pass|auth_request)\b' "$block")
+  fi
+
+  site_names=()
+  needs_tls=true
+  if [[ "$listen_80" == "true" && "$listen_443" == "false" ]]; then
+    needs_tls=false
+  fi
+  for name in "${names[@]}"; do
+    if [[ "$listen_443" == "true" && "$listen_80" == "false" ]]; then
+      site_names+=("https://${name}")
+    elif [[ "$listen_80" == "true" && "$listen_443" == "false" ]]; then
+      site_names+=("http://${name}")
+    else
+      site_names+=("$name")
+    fi
+  done
+  site_label="$(join_by_comma "${site_names[@]}")"
+
+  {
+    echo "# Source block: ${block_id}"
+    echo "${site_label} {"
+
+    if [[ "$TLS_MODE" == "cloudflare" && "$needs_tls" == "true" ]]; then
+      echo "    tls {"
+      echo "        dns cloudflare {env.CF_API_TOKEN}"
+      echo "    }"
+      echo
+    elif [[ "$TLS_MODE" == "existing" && "$needs_tls" == "true" ]]; then
+      if [[ -n "$ssl_cert" && -n "$ssl_key" ]]; then
+        echo "    tls ${ssl_cert} ${ssl_key}"
+        echo
+      elif [[ "$listen_443" == "true" ]]; then
+        warn "${block_id}: listen 443 detected but ssl_certificate/ssl_certificate_key missing"
+        unsupported_count=$((unsupported_count + 1))
+      fi
+    fi
+
+    emitted_route=false
+
+    if [[ -n "$redirect_code" && -n "$redirect_target" && -z "$map_lines" ]]; then
+      if [[ "$redirect_code" == "301" ]]; then
+        echo "    redir ${redirect_target} permanent"
+      elif [[ "$redirect_code" == "302" ]]; then
+        echo "    redir ${redirect_target} temporary"
+      else
+        echo "    redir ${redirect_target} ${redirect_code}"
+      fi
+      emitted_route=true
+    fi
+
+    if [[ -n "$map_lines" ]]; then
+      while IFS='|' read -r loc_expr proxy_target insecure_tls; do
+        [[ -z "$loc_expr" || -z "$proxy_target" ]] && continue
+        resolved_proxy_target="$(resolve_proxy_target "$proxy_target" "$block_id")"
+
+        modifier="prefix"
+        path_expr="$loc_expr"
+
+        if [[ "$loc_expr" =~ ^([=~\^]+)[[:space:]]+(.+)$ ]]; then
+          modifier="${BASH_REMATCH[1]}"
+          path_expr="${BASH_REMATCH[2]}"
+        fi
+
+        case "$modifier" in
+          "~"|"~*"|"^~")
+            warn "${block_id}: location modifier '${modifier}' for '${path_expr}' requires manual conversion"
+            unsupported_count=$((unsupported_count + 1))
+            continue
+            ;;
+          "=")
+            if [[ "$path_expr" == /* ]]; then
+              echo "    handle ${path_expr} {"
+              if [[ "$insecure_tls" == "1" && "$resolved_proxy_target" == https://* ]]; then
+                echo "        reverse_proxy ${resolved_proxy_target} {"
+                echo "            transport http {"
+                echo "                tls_insecure_skip_verify"
+                echo "            }"
+                echo "        }"
+              else
+                echo "        reverse_proxy ${resolved_proxy_target}"
+              fi
+              echo "    }"
+              emitted_route=true
+            else
+              warn "${block_id}: exact location '${loc_expr}' is not a path; manual conversion required"
+              unsupported_count=$((unsupported_count + 1))
+            fi
+            ;;
+          *)
+            if [[ "$path_expr" == "/" ]]; then
+              if [[ "$insecure_tls" == "1" && "$resolved_proxy_target" == https://* ]]; then
+                echo "    reverse_proxy ${resolved_proxy_target} {"
+                echo "        transport http {"
+                echo "            tls_insecure_skip_verify"
+                echo "        }"
+                echo "    }"
+              else
+                echo "    reverse_proxy ${resolved_proxy_target}"
+              fi
+              emitted_route=true
+            elif [[ "$path_expr" == /* ]]; then
+              clean_path="${path_expr%/}"
+              [[ -z "$clean_path" ]] && clean_path="/"
+              echo "    handle ${clean_path} {"
+              if [[ "$insecure_tls" == "1" && "$resolved_proxy_target" == https://* ]]; then
+                echo "        reverse_proxy ${resolved_proxy_target} {"
+                echo "            transport http {"
+                echo "                tls_insecure_skip_verify"
+                echo "            }"
+                echo "        }"
+              else
+                echo "        reverse_proxy ${resolved_proxy_target}"
+              fi
+              echo "    }"
+              echo "    handle_path ${clean_path}/* {"
+              if [[ "$insecure_tls" == "1" && "$resolved_proxy_target" == https://* ]]; then
+                echo "        reverse_proxy ${resolved_proxy_target} {"
+                echo "            transport http {"
+                echo "                tls_insecure_skip_verify"
+                echo "            }"
+                echo "        }"
+              else
+                echo "        reverse_proxy ${resolved_proxy_target}"
+              fi
+              echo "    }"
+              emitted_route=true
+            else
+              warn "${block_id}: location '${loc_expr}' is not a simple path; manual conversion required"
+              unsupported_count=$((unsupported_count + 1))
+            fi
+            ;;
+        esac
+      done <<< "$map_lines"
+    fi
+
+    if [[ "$emitted_route" == false ]]; then
+      echo "    respond \"No automatic route generated for this server block\" 404"
+      warn "${block_id}: no proxy_pass/redirect converted; added placeholder response"
+      unsupported_count=$((unsupported_count + 1))
+    fi
+
+    echo "}"
+    echo
+  } >> "$OUTPUT_FILE"
+
+  converted_blocks=$((converted_blocks + 1))
+done
+
+if [[ ! -s "$WARNINGS_FILE" ]]; then
+  echo "No warnings." > "$WARNINGS_FILE"
+fi
+
+log_success "Generated Caddyfile: $OUTPUT_FILE"
+log_info "Converted server blocks: $converted_blocks / $server_count"
+log_info "Warnings report: $WARNINGS_FILE"
+
+if [[ "$STRICT" == "true" && "$unsupported_count" -gt 0 ]]; then
+  log_error "Strict mode enabled: ${unsupported_count} warning(s) found"
+  exit 1
+fi

setup/nginx-to-caddy/validate_caddy.sh

@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+# shellcheck source=./lib.sh
+source "$SCRIPT_DIR/lib.sh"
+
+CONFIG_FILE="$SCRIPT_DIR/output/Caddyfile.generated"
+FORMAT_FILE=true
+USE_DOCKER=false
+DO_ADAPT=true
+DO_VALIDATE=true
+CADDY_IMAGE="caddy:2"
+
+usage() {
+  cat <<USAGE
+Usage: $(basename "$0") [options]
+
+Format/adapt/validate a generated Caddyfile.
+
+Options:
+  --config=PATH       Caddyfile to validate (default: setup/nginx-to-caddy/output/Caddyfile.generated)
+  --no-format         Skip caddy fmt
+  --no-adapt          Skip caddy adapt
+  --no-validate       Skip caddy validate
+  --docker            Use Docker image instead of local caddy binary
+  --image=NAME        Docker image when --docker is used (default: caddy:2)
+  --help, -h          Show help
+USAGE
+}
+
+for arg in "$@"; do
+  case "$arg" in
+    --config=*) CONFIG_FILE="${arg#*=}" ;;
+    --no-format) FORMAT_FILE=false ;;
+    --no-adapt) DO_ADAPT=false ;;
+    --no-validate) DO_VALIDATE=false ;;
+    --docker) USE_DOCKER=true ;;
+    --image=*) CADDY_IMAGE="${arg#*=}" ;;
+    --help|-h) usage; exit 0 ;;
+    *) log_error "Unknown argument: $arg"; usage; exit 1 ;;
+  esac
+done
+
+if [[ ! -f "$CONFIG_FILE" ]]; then
+  log_error "Config file not found: $CONFIG_FILE"
+  exit 1
+fi
+
+if [[ "$USE_DOCKER" == "true" ]]; then
+  require_cmd docker
+
+  if [[ "$FORMAT_FILE" == "true" ]]; then
+    log_info "Formatting Caddyfile with Docker..."
+    docker run --rm \
+      -v "$CONFIG_FILE:/etc/caddy/Caddyfile" \
+      "$CADDY_IMAGE" caddy fmt --overwrite /etc/caddy/Caddyfile
+  fi
+
+  if [[ "$DO_ADAPT" == "true" ]]; then
+    log_info "Adapting Caddyfile (Docker)..."
+    docker run --rm \
+      -v "$CONFIG_FILE:/etc/caddy/Caddyfile:ro" \
+      "$CADDY_IMAGE" caddy adapt --config /etc/caddy/Caddyfile --adapter caddyfile >/dev/null
+  fi
+
+  if [[ "$DO_VALIDATE" == "true" ]]; then
+    log_info "Validating Caddyfile (Docker)..."
+    docker run --rm \
+      -v "$CONFIG_FILE:/etc/caddy/Caddyfile:ro" \
+      "$CADDY_IMAGE" caddy validate --config /etc/caddy/Caddyfile --adapter caddyfile
+  fi
+else
+  require_cmd caddy
+
+  if [[ "$FORMAT_FILE" == "true" ]]; then
+    log_info "Formatting Caddyfile..."
+    caddy fmt --overwrite "$CONFIG_FILE"
+  fi
+
+  if [[ "$DO_ADAPT" == "true" ]]; then
+    log_info "Adapting Caddyfile..."
+    caddy adapt --config "$CONFIG_FILE" --adapter caddyfile >/dev/null
+  fi
+
+  if [[ "$DO_VALIDATE" == "true" ]]; then
+    log_info "Validating Caddyfile..."
+    caddy validate --config "$CONFIG_FILE" --adapter caddyfile
+  fi
+fi
+
+log_success "Validation checks complete"