Rename folders

workflow-parser/src/model/converter/cron.ts

@@ -0,0 +1,115 @@
+import cronstrue from "cronstrue";
+
+import {MONTH_RANGE, HOUR_RANGE, MINUTE_RANGE, DOM_RANGE, DOW_RANGE} from "./cron-constants";
+
+type Range = {
+  min: number;
+  max: number;
+  names?: Record<string, number>;
+};
+
+export function isValidCron(cron: string): boolean {
+  // https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#schedule
+
+  const parts = cron.split(/ +/);
+  if (parts.length != 5) {
+    return false;
+  }
+  const [minutes, hours, dom, months, dow] = parts;
+
+  return (
+    validateCronPart(minutes, MINUTE_RANGE) &&
+    validateCronPart(hours, HOUR_RANGE) &&
+    validateCronPart(dom, DOM_RANGE) &&
+    validateCronPart(months, MONTH_RANGE) &&
+    validateCronPart(dow, DOW_RANGE)
+  );
+}
+
+export function getCronDescription(cronspec: string): string | undefined {
+  if (!isValidCron(cronspec)) {
+    return;
+  }
+
+  let desc = "";
+  try {
+    desc = cronstrue.toString(cronspec, {
+      dayOfWeekStartIndexZero: true,
+      monthStartIndexZero: false,
+      use24HourTimeFormat: true,
+      // cronstrue sets the description as the error if throwExceptionOnParseError is false
+      // so we need to distinguish between an error and a valid description
+      throwExceptionOnParseError: true
+    });
+  } catch (err) {
+    return;
+  }
+
+  // Make first character lowercase
+  let result = "Runs " + desc.charAt(0).toLowerCase() + desc.slice(1);
+  result +=
+    "\n\nActions schedules run at most every 5 minutes." +
+    " [Learn more](https://docs.github.com/actions/using-workflows/workflow-syntax-for-github-actions#onschedule)";
+  return result;
+}
+
+function validateCronPart(value: string, range: Range, allowSeparators = true): boolean {
+  if (range.names && range.names[value.toLowerCase()] !== undefined) {
+    return true;
+  }
+
+  if (value === "*") {
+    return true;
+  }
+
+  // Operator precedence: , > / > -
+  if (value.includes(",")) {
+    if (!allowSeparators) {
+      return false;
+    }
+    return value.split(",").every(v => v && validateCronPart(v, range));
+  }
+
+  if (value.includes("/")) {
+    if (!allowSeparators) {
+      return false;
+    }
+
+    const [start, step, ...rest] = value.split("/");
+    const stepNumber = +step;
+    if (rest.length > 0 || isNaN(stepNumber) || stepNumber <= 0 || !start || !step) {
+      return false;
+    }
+
+    // Separators are only allowed in the part before the `/`, e.g. `1-5/2`
+    return validateCronPart(start, range) && validateCronPart(step, range, false);
+  }
+
+  if (value.includes("-")) {
+    if (!allowSeparators) {
+      return false;
+    }
+
+    const [start, end, ...rest] = value.split("-");
+    if (rest.length > 0 || !start || !end) {
+      return false;
+    }
+
+    // Convert name to integers so we can make sure end >= start
+    const startNumber = convertToNumber(start, range.names);
+    const endNumber = convertToNumber(end, range.names);
+    return validateCronPart(start, range, false) && validateCronPart(end, range, false) && endNumber >= startNumber;
+  }
+
+  const number = +value;
+  return !isNaN(number) && number >= range.min && number <= range.max;
+}
+
+// Converts a string integer or a short name to a number
+function convertToNumber(value: string, names?: Record<string, number>): number {
+  if (names && names[value.toLowerCase()] !== undefined) {
+    return +names[value.toLowerCase()];
+  } else {
+    return +value;
+  }
+}