MergeStorydemo-repofeature/retry

Retry temporary failures with exponential backoff

WeatherClient.getForecast now retries network errors, 429 and 5xx through a new withRetry helper, with full-jitter backoff and support for Retry-After. Other 4xx errors still fail at once.

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What to review

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The mission1 line
  • The weather client now retries temporary failures on its own. Commit ea92200: Retry temporary failures with exponential backoffsrc/retry.tsTask description
The problem2 lines
  • When the API is busy, forecasts fail with 429, 503 or a network error. Callers retry by hand. Task description
  • The task: retry those failures with exponential backoff, and respect Retry-After. Task descriptionWeatherClient.getForecast (src/client.ts:46-66)
Where the change lives2 lines
  • The retry loop lives in a new helper, withRetry, so other calls can use it later. src/retry.tswithRetry (src/retry.ts:27-43)Implementation notes
  • getForecast sends every request through it, and loadConfig reads three new retry settings. src/client.ts:45-67WeatherClient.getForecast (src/client.ts:46-66)src/config.ts:9-16loadConfig (src/config.ts:8-16)
The retry loop3 lines
  • withRetry fills in defaults from DEFAULT_RETRY, then runs the operation in a loop. withRetry (src/retry.ts:27-43)DEFAULT_RETRY (src/retry.ts:8)src/retry.ts:1-43
  • On a final error, or after the last allowed retry, it throws the error. withRetry (src/retry.ts:27-43)src/retry.ts:1-43
  • Otherwise it waits: afterMs if the decision has one, or else backoffDelay. withRetry (src/retry.ts:27-43)src/retry.ts:1-43
The retry policy3 lines
  • The defaults: three retries, a 250 millisecond base delay and a four second cap. DEFAULT_RETRY (src/retry.ts:8)Check the changed timeout, retry or interval valuessrc/retry.ts:1-43
  • isRetryableStatus accepts only 429 and 5xx. isRetryableStatus (src/retry.ts:17-19)src/retry.ts:1-43
  • backoffDelay picks a random wait below a limit that doubles each time. That is full jitter. backoffDelay (src/retry.ts:22-25)src/retry.ts:1-43Implementation notes
What is retried, and what is not3 lines
  • retryDecision retries a WeatherError only for 429 and 5xx. A 404 fails at once. retryDecision (src/client.ts:31-37)src/client.ts:9-41Implementation notes
  • A TypeError means fetch got no response, so it is retried as a network error. retryDecision (src/client.ts:31-37)src/client.ts:9-41
  • retryAfterMs reads Retry-After, in seconds or as a date. That wait replaces the backoff. retryAfterMs (src/client.ts:22-28)src/client.ts:9-41Implementation notes
One request during an outage3 lines
  • Before, the first failure went straight back to the caller. src/client.ts:45-67
  • Now, in the first new test, no response means a backoff wait, and a 503 waits as Retry-After says. test/retry.test.ts:1-49src/client.ts:9-41src/retry.ts:1-43
  • The third attempt returns the forecast. test/retry.test.ts:1-49src/client.ts:45-67
What to review4 lines
  • The timeout applies per attempt, so the worst case grows with every retry. Implementation notessrc/client.ts:45-67
  • A long Retry-After is used as sent, without the maxDelayMs cap. Implementation notessrc/retry.ts:1-43
  • Timeouts are not retried, but any TypeError is, even one from a bug. Implementation notesretryDecision (src/client.ts:31-37)src/client.ts:9-41
  • And WeatherError and WeatherConfig changed shape, so check the callers. Confirm callers still match the changed signaturesWeatherError.constructor (src/client.ts:14-18)WeatherConfig (src/config.ts:3-6)
Wrap up2 lines
  • Temporary failures now retry with jittered backoff. Other 4xx errors fail at once. WeatherClient.getForecast (src/client.ts:46-66)retryDecision (src/client.ts:31-37)src/retry.ts:1-43
  • The coding agent reports that npm test passed. Test run: npm test (passed, reported by the caller)test/retry.test.ts:1-49

What the video could not confirm

How it was made

Storyboard
Written by a coding agent.
Voice
Kokoro (local)
Generated
2026-11-11
Commit
ea92200