argoproj/applicationset v0.3.0 on GitHub

I am happy to announce the latest release of the Argo CD ApplicationSet controller, v0.3.0. Many new features were contributed as part of this release, including two new generators, improved error reporting and handling, support for webhook-based refresh trigger, plus doc updates, usability improvements, stability fixes, and more.

You can learn more about this release from the ApplicationSet documentation, or check out the project repository and learn how you can contribute.

Contributors

Thanks to all the folks who have contributed to the ApplicationSet controller since our last release!

Shunya Murata (@shmurata)
Michael Crenshaw (@crenshaw-dev)
Jonathan West (@jgwest)
Ishita Sequeira (@ishitasequeira)
Chetan Banavikalmutt (@chetan-rns)
Alexander Matyushentsev (@alexmt)
Shiv Jha-Mathur (@shivjm)
Subhash Chandra (@TMaYaD)
William Tam (@wtam2018)
Benoit Gaillard (@benoitg31)
Michal Barecki (@mbarecki)
Guillaume Dupin (@yogeek)
Krzysztof Dąbrowski (@krzysdabro)
Olve S. Hansen (@olvesh)
Dewan Ishtiaque Ahmed (@dewan-ahmed)
Diego Pomares (@DiegoPomares)

Want to join us for our next release? Check out the project repository (https://github.com/argoproj-labs/applicationset) or visit us on #argo-cd-appset on Slack.

New in this release

New generator: Pull Request generator

With ApplicationSet v0.3.0, a new Pull Request generator has been contributed which uses the API of an SCMaaS provider (e.g. GitHub) to automatically discover open pull requests within an repository. This fits well with users that wish to construct a test environment based on an open pull request.

In this example, we will create an Argo CD Application resource for each open pull request:

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: myapps
spec:
  generators:
  - pullRequest:
      github:
        # The GitHub organization or user.
        owner: myorg
        # The Github repository
        repo: myrepository
        # For GitHub Enterprise (optional)
        api: https://git.example.com/
        # Reference to a Secret containing an access token. (optional)
        tokenRef:
          secretName: github-token
          key: token
        # Labels is used to filter the PRs that you want to target. (optional)
        labels:
        - preview
  template:
  # (template the Application using PR generator params)...

To learn more, check out the Pull Request generator documentation for details. Contributed by @shmurata.

New generator: Merge generator

Also new in this release is the Merge generator, which is useful when you want to selectively override the parameters generated by one generator, with those generated by another.

In this example, we first gather the list of clusters from Argo CD, then we 'patch' only those clusters with label use-kakfa: false, and finally we enable redis on a specfic cluster:

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: cluster-git
spec:
  generators:
    # merge 'parent' generator
    - merge:
        mergeKeys:
          - server
        generators:
          # Generate parameters for all Argo CD clusters
          - clusters:
              values:
                kafka: 'true'
                redis: 'false'
          # For clusters with a specific label, enable Kafka.
          - clusters:
              selector:
                matchLabels:
                  use-kafka: 'false'
              values:
                kafka: 'false'
          # For a specific cluster, enable Redis.
          - list:
              elements: 
                - server: https://2.4.6.8
                  values.redis: 'true'

See the Merge generator documentation for a full example, and for details on generator behaviour. Contributed by @crenshaw-dev.

Report error conditions/status for ApplicationSet CR

When the user-provided generator/template produces invalid Argo CD Applications, the ApplicationSet resource's status field will now report errors (or the lack thereof). Here is an example of the new status conditions:

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: myapps
spec:
  generators: # (...)
  template: # (...)
status:
  conditions:
  - lastTransitionTime: "2021-11-23T05:47:08Z"
    type: ErrorOccurred
    status: "False"
    reason: ApplicationSetUpToDate
    message: Successfully generated parameters for all Applications
  - lastTransitionTime: "2021-11-23T05:47:08Z"
    type: ParametersGenerated
    message: Successfully generated parameters for all Applications
    reason: ParametersGenerated
    status: "True"
  - lastTransitionTime: "2021-11-23T05:47:08Z"
    type: ResourcesUpToDate
    status: "True"
    reason: ApplicationSetUpToDate
    message: ApplicationSet up to date

On parameter generation failure or templating failure, those errors will be reported under the appropriate conditions. Contributed by @ishitasequeira.

Git Generator: Refresh ApplicationSet resource with Git generator using webhook

This feature adds support for refreshing ApplicationSets via a GitHub webhook trigger. It exposes a service which listens for incoming webhook payloads, and once received triggers the ApplicationSet controller to regenerate resources. In contrast, with the previous release, the ApplicationSet controller only supported polling the Git repository used by the Git generator every 3 mins (but this is at least customizable).

See the webhook documentation for details. Contributed by @chetan-rns.

This contribution also adds general support for webhooks, which is used by the Pull Request generator webhook code, below.

Gracefully handle application validation errors

This feature changes how the ApplicationSet controller handles ApplicationSets that generate invalid Applications. Previously, if at least one Application in the ApplicationSet was invalid, the controller would refuse to proceed further and would skip all Application processing (i.e. it would 'fail fast'). Now, the controller will process valid Applications, and only skip invalid Applications (logging information about them to the console).

Contributed by @alexmt.

Pull Request generator: Support for webhooks

When using a Pull Request generator, the ApplicationSet controller polls every requeueAfterSeconds interval (defaulting to every 30 minutes) to detect changes. To eliminate this delay from polling, the ApplicationSet webhook server can be configured to receive webhook events, which will refresh the parameters generated by the Pull Request generator, and thus the corresponding Application resources.

More information on configuring webhooks with the Pull Request generator is available from the Pull Request generator documentation. Contributed by @shmurata.

Improve Git files generator performance (#355)

The Git files generator was consuming too much time (and driving up Git requests) due to inadvertently executing 'git fetch/git checkout' for each discovered file within the repository. With ApplicationSet v0.3.0, that has improved such that we will now issue a Git checkout/fetch repo once per refresh. Contributed by @alexmt.

Support `-logformat=json` as parameter to applicationset-controller

This feature adds a new --logformat=json parameter to the applicationset-controller, which switches the logging output of the ApplicationSet controller to JSON. Contributed by @shivjm.

SCM Generator: Provide SHA for latest commit on a branch in variables (#307)

This feature adds SHA to the list of parameters exposed by the SCM Generator, with the SHA parameter representing the latest commit. Contributed by @TMaYaD.

Fixes, test fixes, infrastructure improvements, and documentation updates

Fixes

Fix: new variable for the normalized version of name field (#390, contributed by @chetan-rns)
Fixes GitLab RepoHasPath error handling (#423, contributed by @benoitg31)

Test/infrastructure improvements:

Investigate Argo CD deletion failure messages when running ApplicationSet E2E tests in on-cluster configuration (#392, contributed by @jgwest)
Update master branch VERSION file and metadata, and pull up release changes from 0.2.0 (#343, contributed by @jgwest)
Skip E2E tests that require GitHub token, if not specified (#380, contributed by @jgwest)
API rate limit error in image publish action (#368, contributed by @jgwest)
Disable SCM Provider Unit tests on PRs (#337, contributed by @jgwest)
Fix lint-docs (#411, contributed by @crenshaw-dev)
Fix indentation in example (#360, contributed by @DiegoPomares)
Adding required 'version' field for Helm Charts (#332, contributed by @dewan-ahmed)
Adopt latest Argo CD dependencies, in preparation for next release (#410, contributed by @jgwest)

Doc updates

Update release process docs and include release checklist in docs (#365, contributed by @jgwest)
Fix includeSubgroups reference name (#357, contributed by @yogeek)
Add missing brace (#349, contributed by @krzysdabro)
Fix Git Generator Files path example in docs (#408, contributed by @mbarecki)
Corrected wrong info about path and path.basename (#412, contributed by @olvesh)

Upgrade Notes

When moving from ApplicationSet v0.1.0/v0.2.0, to v0.3.0, there are two behaviour changes to be aware of.

Cluster generator: `{{name}}` parameter value will no longer be normalized, but existing normalization behaviour is preserved in a new `{{nameNormalized}}` parameter

The Cluster generator {{name}} parameter has now reverted to its original behaviour: the cluster name within Argo CD will no longer be normalized. The {{name}} parameter generated by the Cluster generator within the ApplicationSet will now be passed unmodified to the ApplicationSet template.

A new parameter, {{nameNormalized}} has been introduced which preserves the 0.2.0 behaviour. This allows you to choose which behaviour you wish to use in your ApplicationSet, based on the context in which it is used: either using the parameter as defined, or in a normalized form (which allows it to be used in the name field of an Application resource.)

If your Argo CD cluster names are already valid, no change is required. Otherwise, to preserve the v0.2.0 behaviour of your ApplicationSet, replace {{name}} with {{nameNormalized}} within your ApplicationSet template.

More information about this change is available from the issue.

If an ApplicationSet contains an invalid generated Application, the valid generated Applications will still be processed

The responsibility of the ApplicationSet controller is to convert an ApplicationSet resource into one or more Application resources. However, with the previous releases, if at least one of the generated Application resources was invalid (e.g. it failed the internal validation logic), none of the generated Applications would be processed (they would not be neither created nor modified).

With the latest ApplicationSet release, if a generator generates invalid Applications, those invalid generated Applications will still be skipped, but the valid generated Applications will now be processed (created/modified).

Thus no ApplicationSet resource changes are required by this new behaviour, but it is worth keeping in mind that your ApplicationSets which were previously blocked by a failing Application may no longer be blocked. This change might cause valid Applications to now be created/modified, whereas previously they were prevented from being processed.