Using Workflows to Schedule Jobs
Workflows help you increase the speed of your software development through faster feedback, shorter reruns, and more efficient use of resources. This document describes the Workflows feature and provides example configurations in the following sections:
- Workflows Configuration Examples
- Tips for Advanced Configuration
- Holding a Workflow for a Manual Approval
- Scheduling a Workflow
- Using Contexts and Filtering in Your Workflows
- Using Workspaces to Share Data Among Jobs
- Rerunning a Workflow’s Failed Jobs
A workflow is a set of rules for defining a collection of jobs and their run order. Workflows support complex job orchestration using a simple set of configuration keys to help you resolve failures sooner.
With workflows, you can:
- Run and troubleshoot jobs independently with real-time status feedback.
- Schedule workflows for jobs that should only run periodically.
- Fan-out to run multiple jobs concurrently for efficient version testing.
- Fan-in to quickly deploy to multiple platforms.
For example, if only one job in a workflow fails, you will know it is failing in real-time. Instead of wasting time waiting for the entire build to fail and rerunning the entire job set, you can rerun just the failed job.
Workflows may appear with one of the following states:
- RUNNING: Workflow is in progress
- NOT RUN: Workflow was never started
- CANCELLED: Workflow was cancelled before it finished
- FAILING: A job in the workflow has failed. Workflows go into Failing state when one of the jobs within the graph has failed while other jobs are still running. Failing state indicates that the workflow is eventually going to fail.
- FAILED: One or more jobs in the workflow failed. Failed state is when one or more jobs in the workflow graph have failed. Failed is a terminal state.
- SUCCESS: All jobs in the workflow completed successfully
- ON HOLD: A job in the workflow is waiting for approval
- NEEDS SETUP: A workflow stanza is not included or is incorrect in the config.yml file for this project
- Projects that have pipelines enabled may use the CircleCI API to trigger workflows.
- Config without workflows requires a job called
Refer to the Workflows section of the FAQ for additional information and limitations.
Workflows Configuration Examples
For a full specification of the
workflows key, see the Workflows section of the Configuring CircleCI document.
Note: Projects configured with Workflows often include multiple jobs that share syntax for Docker images, environment variables, or
run steps. Refer the YAML Anchors/Aliases documentation for information about how to alias and reuse syntax to keep your
.circleci/config.yml file small. See the Reuse YAML in the CircleCI Config blog post for a summary.
To run a set of concurrent jobs, add a new
workflows: section to the end of your existing
.circleci/config.yml file with the version and a unique name for the workflow. The following sample
.circleci/config.yml file shows the default workflow orchestration with two concurrent jobs. It is defined by using the
workflows: key named
build_and_test and by nesting the
jobs: key with a list of job names. The jobs have no dependencies defined, therefore they will run concurrently.
jobs: build: docker: - image: circleci/<language>:<version TAG> steps: - checkout - run: <command> test: docker: - image: circleci/<language>:<version TAG> steps: - checkout - run: <command> workflows: version: 2 build_and_test: jobs: - build - test
See the Sample Parallel Workflow config for a full example.
Tips for Advanced Configuration
Using workflows enables users to create much more advanced configurations over running a single set of jobs. With more customizability and control comes more room for error, however. When using workflows try to do the following:
- Move the quickest jobs up to the start of your workflows. For example, lint or syntax checking should happen before longer-running, more computationally expensive jobs.
- Using a “setup” job at the start of a workflow can be helpful to do some preflight checks and populate a workspace for all the following jobs.
Sequential Job Execution Example
The following example shows a workflow with four sequential jobs. The jobs run according to configured requirements, each job waiting to start until the required job finishes successfully as illustrated in the diagram.
config.yml snippet is an example of a workflow configured for sequential job execution:
workflows: version: 2 build-test-and-deploy: jobs: - build - test1: requires: - build - test2: requires: - test1 - deploy: requires: - test2
The dependencies are defined by setting the
requires: key as shown. The
deploy: job will not run until the
test2 jobs complete successfully. A job must wait until all upstream jobs in the dependency graph have run. So, the
deploy job waits for the
test2 job, the
test2 job waits for the
test1 job and the
test1 job waits for the
See the Sample Sequential Workflow config for a full example.
Fan-Out/Fan-In Workflow Example
The illustrated example workflow runs a common build job, then fans-out to run a set of acceptance test jobs concurrently, and finally fans-in to run a common deploy job.
config.yml snippet is an example of a workflow configured for fan-out/fan-in job execution:
workflows: version: 2 build_accept_deploy: jobs: - build - acceptance_test_1: requires: - build - acceptance_test_2: requires: - build - acceptance_test_3: requires: - build - acceptance_test_4: requires: - build - deploy: requires: - acceptance_test_1 - acceptance_test_2 - acceptance_test_3 - acceptance_test_4
In this example, as soon as the
build job finishes successfully, all four acceptance test jobs start. The
deploy job must wait for all four acceptance test jobs to complete successfully before it starts.
See the Sample Fan-in/Fan-out Workflow config for a full example.
Holding a Workflow for a Manual Approval
Workflows can be configured to wait for manual approval of a job before
continuing to the next job. Anyone who has push access to the repository can click the Approval button to continue the workflow.
To do this, add a job to the
jobs list with the
type: approval. Let’s look at a commented config example.
# ... # << Your config for the build, test1, test2, and deploy jobs >> # ... workflows: version: 2 build-test-and-approval-deploy: jobs: - build # your custom job from your config, that builds your code - test1: # your custom job; runs test suite 1 requires: # test1 will not run until the `build` job is completed. - build - test2: # another custom job; runs test suite 2, requires: # test2 is dependent on the succes of job `test1` - test1 - hold: # <<< A job that will require manual approval in the CircleCI web application. type: approval # <<< This key-value pair will set your workflow to a status of "On Hold" requires: # We only run the "hold" job when test2 has succeeded - test2 # On approval of the `hold` job, any successive job that requires the `hold` job will run. # In this case, a user is manually triggering the deploy job. - deploy: requires: - hold
The outcome of the above example is that the
deploy: job will not run until
you click the
hold job in the Workflows page of the CircleCI app and then
click Approve. In this example the purpose of the
hold job is to wait for
approval to begin deployment. A job can be approved for up to 15 days after
Some things to keep in mind when using manual approval in a workflow:
approvalis a special job type that is only available to jobs under the
holdjob must be a unique name not used by any other job.
- that is, your custom configured jobs, such as
test1in the example above wouldn’t be given a
- The name of the job to hold is arbitrary - it could be
pause, for example, as long as the job has a
type: approvalkey in it.
- All jobs that are to run after a manually approved job must
require:the name of that job. Refer to the
deploy:job in the above example.
- Jobs run in the order defined until the workflow processes a job with the
type: approvalkey followed by a job on which it depends.
The following screenshot demonstrates a workflow on hold.
By clicking on the pending job’s name (
build, in the screenshot above ), an approval dialog box appears requesting that you approve or cancel the holding job.
After approving, the rest of the workflow runs as directed.
Scheduling a Workflow
It can be inefficient and expensive to run a workflow for every commit for every branch. Instead, you can schedule a workflow to run at a certain time for specific branches. This will disable commits from triggering jobs on those branches.
Consider running workflows that are resource-intensive or that generate reports on a schedule rather than on every commit by adding a
triggers key to the configuration. The
triggers key is only added under your
workflows key. This feature enables you to schedule a workflow run by using
cron syntax to represent Coordinated Universal Time (UTC) for specified branches.
Note: In CircleCI v2.1, when no workflow is provided in config, an implicit one is used. However, if you declare a workflow to run a scheduled build, the implicit workflow is no longer run. You must add the job workflow to your config in order for CircleCI to also build on every commit.
Note: Please note that when you schedule a workflow, the workflow will be counted as an individual user seat.
By default, a workflow is triggered on every
git push. To trigger a workflow on a schedule, add the
triggers key to the workflow and specify a
In the example below, the
nightly workflow is configured to run every day at 12:00am UTC. The
cron key is specified using POSIX
crontab syntax, see the crontab man page for
cron syntax basics. The workflow will be run on the
Note: Scheduled workflows may be delayed by up to 15 minutes. This is done to maintain reliability during busy times such as 12:00am UTC. Scheduled workflows should not assume they are started with to-the-minute accuracy.
workflows: version: 2 commit: jobs: - test - deploy nightly: triggers: - schedule: cron: "0 0 * * *" filters: branches: only: - master - beta jobs: - coverage
In the above example, the
commit workflow has no
triggers key and will run on every
git push. The
nightly workflow has a
triggers key and will run on the specified
Specifying a Valid Schedule
schedule requires a
cron key and a
The value of the
cron key must be a valid crontab entry.
Cron step syntax (for example,
*/20) is not supported. Range elements within comma-separated lists of elements are also not supported.
The value of the
filters key must be a map that defines rules for execution on specific branches.
For more details, see the
branches section of the Configuring CircleCI document.
For a full configuration example, see the Sample Scheduled Workflows configuration.
Using Contexts and Filtering in Your Workflows
The following sections provide example for using Contexts and filters to manage job execution.
Using Job Contexts to Share Environment Variables
The following example shows a workflow with four sequential jobs that use a context to share environment variables. See the Contexts document for detailed instructions on this setting in the application.
config.yml snippet is an example of a sequential job workflow configured to use the resources defined in the
workflows: version: 2 build-test-and-deploy: jobs: - build - test1: requires: - build context: org-global - test2: requires: - test1 context: org-global - deploy: requires: - test2
The environment variables are defined by setting the
context key as shown to the default name
test2 jobs in this workflows example will use the same shared environment variables when initiated by a user who is part of the organization. By default, all projects in an organization have access to contexts set for that organization.
Branch-Level Job Execution
The following example shows a workflow configured with jobs on three branches: Dev, Stage, and Pre-Prod. Workflows will ignore
branches keys nested under
jobs configuration, so if you use job-level branching and later add workflows, you must remove the branching at the job level and instead declare it in the workflows section of your
config.yml, as follows:
config.yml snippet is an example of a workflow configured for branch-level job execution:
workflows: version: 2 dev_stage_pre-prod: jobs: - test_dev: filters: # using regex filters requires the entire branch to match branches: only: # only branches matching the below regex filters will run - dev - /user-.*/ - test_stage: filters: branches: only: stage - test_pre-prod: filters: branches: only: /pre-prod(?:-.+)?$/
For more information on regular expressions, see the Using Regular Expressions to Filter Tags And Branches section below.
For a full example of workflows, see the configuration file for the Sample Sequential Workflow With Branching project.
Executing Workflows for a Git Tag
CircleCI does not run workflows for tags unless you explicitly specify tag filters. Additionally, if a job requires any other jobs (directly or indirectly), you must use regular expressions to specify tag filters for those jobs. Both lightweight and annotated tags are supported.
In the example below, two workflows are defined:
buildjob for all branches.
buildfor all branches and all tags starting with
workflows: version: 2 untagged-build: jobs: - build tagged-build: jobs: - build: filters: tags: only: /^v.*/
In the example below, two jobs are defined within the
buildjob runs for all branches and all tags.
deployjob runs for no branches and only for tags starting with ‘v’.
workflows: version: 2 build-n-deploy: jobs: - build: filters: # required since `deploy` has tag filters AND requires `build` tags: only: /.*/ - deploy: requires: - build filters: tags: only: /^v.*/ branches: ignore: /.*/
In the example below, three jobs are defined with the
buildjob runs for all branches and only tags starting with ‘config-test’.
testjob runs for all branches and only tags starting with ‘config-test’.
deployjob runs for no branches and only tags starting with ‘config-test’.
workflows: version: 2 build-test-deploy: jobs: - build: filters: # required since `test` has tag filters AND requires `build` tags: only: /^config-test.*/ - test: requires: - build filters: # required since `deploy` has tag filters AND requires `test` tags: only: /^config-test.*/ - deploy: requires: - test filters: tags: only: /^config-test.*/ branches: ignore: /.*/
Using Regular Expressions to Filter Tags and Branches
CircleCI branch and tag filters support the Java variant of regex pattern matching. When writing filters, CircleCI matches exact regular expressions.
only: /^config-test/ only matches the
config-test tag. To match all tags starting with
only: /^config-test.*/ instead.
Using tags for semantic versioning is a common use case. To match patch versions 3-7 of a 2.1 release, you could write
For full details on pattern-matching rules, see the java.util.regex documentation.
Using Workspaces to Share Data Among Jobs
Each workflow has an associated workspace which can be used to transfer files to downstream jobs as the workflow progresses. The workspace is an additive-only store of data. Jobs can persist data to the workspace. This configuration archives the data and creates a new layer in an off-container store. Downstream jobs can attach the workspace to their container filesystem. Attaching the workspace downloads and unpacks each layer based on the ordering of the upstream jobs in the workflow graph.
Use workspaces to pass along data that is unique to this run and which is needed for downstream jobs. Workflows that include jobs running on multiple branches may require data to be shared using workspaces. Workspaces are also useful for projects in which compiled data are used by test containers.
For example, Scala projects typically require lots of CPU for compilation in the build job. In contrast, the Scala test jobs are not CPU-intensive and may be parallelised across containers well. Using a larger container for the build job and saving the compiled data into the workspace enables the test containers to use the compiled Scala from the build job.
A second example is a project with a
build job that builds a jar and saves it to a workspace. The
build job fans-out into the
code-coverage to run those tests concurrently using the jar.
To persist data from a job and make it available to other jobs, configure the job to use the
persist_to_workspace key. Files and directories named in the
paths: property of
persist_to_workspace will be uploaded to the workflow’s temporary workspace relative to the directory specified with the
root key. The files and directories are then uploaded and made available for subsequent jobs (and re-runs of the workflow) to use.
Configure a job to get saved data by configuring the
attach_workspace key. The following
config.yml file defines two jobs where the
downstream job uses the artifact of the
flow job. The workflow configuration is sequential, so that
flow to finish before it can start.
# Note that the following stanza uses CircleCI 2.1 to make use of a Reusable Executor # This allows defining a docker image to reuse across jobs. # visit https://circleci.com/docs/2.0/reusing-config/#authoring-reusable-executors to learn more. version: 2.1 executors: my-executor: docker: - image: buildpack-deps:jessie working_directory: /tmp jobs: flow: executor: my-executor steps: - run: mkdir -p workspace - run: echo "Hello, world!" > workspace/echo-output # Persist the specified paths (workspace/echo-output) into the workspace for use in downstream job. - persist_to_workspace: # Must be an absolute path, or relative path from working_directory. This is a directory on the container which is # taken to be the root directory of the workspace. root: workspace # Must be relative path from root paths: - echo-output downstream: executor: my-executor steps: - attach_workspace: # Must be absolute path or relative path from working_directory at: /tmp/workspace - run: | if [[ `cat /tmp/workspace/echo-output` == "Hello, world!" ]]; then echo "It worked!"; else echo "Nope!"; exit 1 fi workflows: version: 2 btd: jobs: - flow - downstream: requires: - flow
For a live example of using workspaces to pass data between build and deploy jobs, see the
config.yml that is configured to build the CircleCI documentation.
For additional conceptual information on using workspaces, caching, and artifacts, refer to the Persisting Data in Workflows: When to Use Caching, Artifacts, and Workspaces blog post.
Rerunning a Workflow’s Failed Jobs
When you use workflows, you increase your ability to rapidly respond to failures. To rerun only a workflow’s failed jobs, click the Workflows icon in the app and select a workflow to see the status of each job, then click the Rerun button and select Rerun from failed.
This section describes common problems and solutions for Workflows.
Rerunning Workflows Fails
It has been observed that in some cases, a failure happens before the workflow runs (during pipeline processing). In this case, re-running the workflow will fail even though it was succeeding before the outage. To work around this, push a change to the project’s repository. This will re-run pipeline processing first, and then run the workflow.
Workflows Waiting for Status in GitHub
If you have implemented Workflows on a branch in your GitHub repository, but the status check never completes, there may be status settings in GitHub that you need to deselect. For example, if you choose to protect your branches, you may need to deselect the
ci/circleci status key as this check refers to the default CircleCI 1.0 check, as follows:
ci/circleci checkbox enabled will prevent the status from showing as completed in GitHub when using a workflow because CircleCI posts statuses to GitHub with a key that includes the job by name.
Go to Settings > Branches in GitHub and click the Edit button on the protected branch to deselect the settings, for example https://github.com/your-org/project/settings/branches.
For procedural instructions on how to add Workflows your configuration as you are migrating from a 1.0
circle.ymlfile to a 2.0
.circleci/config.ymlfile, see the Steps to Configure Workflows section of the Migrating from 1.0 to 2.0 document.
For frequently asked questions and answers about Workflows, see the Workflows section of the FAQ.
For demonstration apps configured with Workflows, see the CircleCI Demo Workflows on GitHub.