argocd-renderer

This is a simple Python script for rendering ArgoCD application manifests the same way ArgoCD would do it. This can be useful for using in a CI/CD pipeline for further validation with kyverno or any other tool.

The script processes a given resource YAML file as input and writes the results to an output file. It accomplishes this by copying all the original resources to the output, and additionally, for any ArgoCD applications it encounters, it renders the application manifest and includes all the rendered resources in the output file as well. The process is recursive: all the rendered resources are also processed as if they were input.

Goals

• Render ArgoCD applications as close as possible to how ArgoCD would do it.
• Keep the script simple and easy to understand. One file, no special dependencies.

Compatibility

There is no plan to implement all the rendering options available in ArgoCD. ArgoCD is a complex system with many features some of which require a running Kubernetes cluster. Additionally, certain features would significantly complicate the code.

The following options are supported:

• .spec.source.helm.valuesObject
• .spec.source.helm.releaseName
• .spec.source.helm.parameters
• .spec.source.helm.fileParameters
• .spec.source.helm.values
• .spec.source.helm.valueFiles
• .spec.source.chart
• kustomization.yaml
• directory source

The following features are not supported:

• .spec.source.kustomize is not supported. Use kustomization.yaml file instead.
• .spec.source.directory options are not supported. Note, this means that the only the configuration options are not supported. The directory source itself is supported.
• ApplicationSet is not supported.

Repository access

The script doesn't have an ability to download repositories. Instead, there is an option to call a helper script that can resolve a repository URL to a local path. The helper script is called with the following arguments:

• repo_url: the URL of the repository to resolve.
• revision: the revision to checkout.
• temp_dir: a temporary directory that can be used to store the repository (as a subdirectory in it).

The helper script can either return the resolved path or an empty string if the repository can't be resolved. The implementation of the helper script can either checkout the repository or use a local cache or return a path to an already checked out repository.

See the repo-resolver.sh script for an example.

Installation and requirements

• Python 3 is required.
• PyYaml is required (pip3 install pyyaml or sudo apt-get install python3-yaml, github runner usually have this library already installed).
• kubectl is required for kustomize to work.
• Helm is required to render Helm charts.

Installation is not required. Just a release release of the script and enjoy.

Command line arguments

usage: argocd-renderer.py
           [-h] -o output_yaml_file [-n target_namespace]
           [-r repo_resolver] [-a helm_args] [-k kustomize_args]
           resources_yaml_file

  resources_yaml_file   resources file containing the resources to be used in
                        the argocd application manifest.

options:
  -o output_yaml_file, --output output_yaml_file
                        output file to save the resources rendered for
                        the found argocd application manifests.

  -n target_namespace, --namespace target_namespace
                        target namespace to be used in the argocd application
                        manifest if not explicitly given in the resources file.

  -r repo_resolver, --repo-resolver repo_resolver
                        path to the repository resolver script that takes
                        [repo url, revision, temp_dir] and returns the resolved
                        local path or empty string.

  -a helm_args, --helm-args helm_args
                        json/yaml array of strings to pass as additional
                        arguments to helm command.

  -k kustomize_args, --kustomize-args kustomize_args
                        json/yaml array of strings to pass as additional
                        arguments to kustomize command.