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Note: This page uses Cron with the YAML cron configuration file, which you use if you use tooling based on the gcloud CLI, such as the gcloud CLI, or gcloud CLI-based Maven, Gradle, Eclipse, or IntelliJ plugins. The XML cron configuration file using the AppCfg toolset delivered with the standalone App Engine SDK has been shut down.The App Engine Cron Service allows you to configure regularly scheduled tasks that operate at defined times or regular intervals. These tasks are commonly known as cron jobs. These cron jobs are automatically triggered by the App Engine Cron Service. For instance, you might use a cron job to send out an email report on a daily basis, or to update some cached data every 10 minutes, or refresh summary information once an hour.
A cron job makes a scheduled HTTP GET
request to the specified endpoint in the same app where the cron job is configured. The handler for that endpoint executes the logic when it is called.
The App Engine Cron Service cannot be used to call web endpoints outside the App Engine host app. It cannot be used to call App Engine endpoints from other apps besides the host app.
A cron job request is subject to the same limits as those for push task queues.
Before you beginTo deploy or update schedules, your account requires one of the following IAM roles:
You can set the permission on the IAM page in the Google Cloud console.
Creating a cron jobcron.yaml
file in the root directory of your application (alongside app.yaml
).Add one or more <cron>
entries to your file and define the necessary elements for your job, including the required <url>
and <schedule>
elements. Review the cron.yaml syntax and options for more details about the elements of the cron.yaml
file.
The following example creates a basic cron job that runs daily:
cron:
- description: "daily summary job"
url: /tasks/summary
target: beta
schedule: every 24 hours
The target specification is optional and is the name of a service/version. If present, the target is prepended to your app's hostname, causing the job to be routed to that service/version. If no target is specified, the job will run in the versions of the default
service that are configured for traffic.
Create a handler for the cron job URL. The handler should execute any tasks that you want scheduled. The handler should respond with an HTTP status code between 200 and 299 (inclusive) to indicate success. Other status codes can be returned and can be used to retry the cron job.
The handler can be as simple as a Servlet in the app. The Servlet URL mapping in
web.xml
should be the same as the cron job URL.
Testing cron jobs in the development serverThe local development server doesn't automatically run your cron jobs. You can make requests directly to your cron job's URL to test your functionality. You can use your local cron or scheduled tasks interface to trigger the URLs of your jobs with curl or a similar tool.
Retrying cron jobs that failIf a cron job's request handler returns a status code that is not in the range 200–299 (inclusive) App Engine considers the job to have failed. By default, failed jobs are not retried unless a 503 status code is returned, in which case it is retried every minute until it succeeds or returns a 200-299 status code.
To set failed jobs to be retried:
retry_parameters
block in your cron.yaml
file.Choose and set the retry parameters in the retry_parameters
block.
For example, this sample cron.yaml
file contains a single cron job that is configured to retry up to five times (the default) with a starting backoff of 2.5 seconds that doubles each time.
cron:
- description: "retry demo"
url: /retry
schedule: every 10 mins
retry_parameters:
min_backoff_seconds: 2.5
max_doublings: 5
Learn more about the cron retry options.
Deploying cron jobsTo deploy the cron jobs specified in your cron.yaml
configuration file, run the following command:
gcloud app deploy cron.yaml
Maven
mvn appengine:deployCron cron.yaml
Gradle
gradle appengineDeployCron cron.yaml
IDE
If you use IntelliJ or Eclipse, select the individual configuration files to be deployed using the deployment form.
Deleting all cron jobsTo delete all cron jobs:
Edit the contents of the cron.yaml
file to:
cron:
Deploy the cron.yaml
file to App Engine.
A cron handler is just a normal handler defined in app.yaml
. You can prevent users from accessing URLs used by scheduled tasks by restricting access to administrator accounts. Scheduled tasks can access admin-only URLs. You can restrict a URL by adding login: admin
to the handler configuration in app.yaml
.
An example might look like this in app.yaml
:
application: hello-cron
version: 1
runtime: java
api_version: 1
handlers:
- url: /report/weekly
servlet: mysite.server.CronServlet
login: admin
Note: While cron jobs can use URL paths restricted with login: admin
, they cannot use URL paths restricted with login: required
because cron scheduled tasks are not run as any user. The admin
restriction is satisfied by the inclusion of the X-Appengine-Cron
header described below.
To test a cron job, sign in as an administrator and visit the URL of the handler in your browser.
Requests from the Cron Service will also contain a HTTP header:
X-Appengine-Cron: true
The X-Appengine-Cron
header is set internally by App Engine. If your request handler finds this header it can trust that the request is a cron request. If the header is present in an external user request to your app, it is stripped, except for requests from logged in administrators of the application, who are allowed to set the header for testing purposes.
App Engine issues Cron requests from the IP address 0.1.0.2
. For Cron jobs created with older gcloud versions (earlier than 326.0.0), Cron requests will come from 0.1.0.1
.
You cannot specify a Google Cloud Endpoint in the url
field of a cron job. If you want your cron job to call a Google Cloud Endpoint, issue a request to a target that is served by a handler in your app, and call the endpoint class and method from the handler code.
You can view scheduled cron jobs in Cloud Scheduler's App Engine Cron Jobs tab.
You can also view logs to see when cron jobs were added or removed.
Learn moreSee detailed information about defining cron jobs in the cron.yaml Reference.
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2025-08-07 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-07 UTC."],[[["The App Engine Cron Service allows the configuration of regularly scheduled tasks, known as cron jobs, which are triggered automatically to perform actions like sending email reports or updating cached data."],["Cron jobs are configured in a `cron.yaml` file within the application's root directory, and they operate by making scheduled HTTP `GET` requests to specified endpoints within the same app."],["To create a cron job, you define the job in `cron.yaml`, specifying elements like the URL to be called and the schedule, and then you must create a handler in the app for the cron job URL to execute the desired tasks."],["Cron job requests that fail (returning a status code outside 200-299) can be configured for retries by adding a `retry_parameters` block to the `cron.yaml` file, allowing control over the number of retries and backoff times."],["Security for cron job URLs can be managed by restricting access to administrator accounts via the `login: admin` setting in `app.yaml`, and the presence of the `X-Appengine-Cron: true` header indicates a request is from the Cron Service."]]],[]]
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