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Rendering Methods🔗

Argo CD Diff Preview supports three different ways to render application manifests. You can choose the rendering method using the --render-method flag.

1. CLI (cli)🔗

The cli method is the most traditional way to generate manifests.

  • How it works: It executes the argocd app manifests command via the Argo CD CLI binary against the ephemeral cluster for every application.
  • Characteristics: Highly reliable, because it authenticates and manages connections automatically. However, it is more restrictive, as it will throw the exact same errors users are accustomed to seeing in the Argo CD UI. It is also slower because it must wait for all applications to reach the "OutOfSync" state before it can render the manifests.
  • Note: The Argo CD CLI binary is not included in the Docker image. If you want to use this render method, you must install the argocd binary yourself (either by extending the Docker image or by running the argocd-diff-preview binary directly in your pipeline).

2. Server API (server-api) - Default🔗

The server-api method is the default rendering method. It improves performance by communicating directly with Argo CD's APIs.

  • How it works: It communicates directly with the Argo CD API server over persistent gRPC connections to request manifest rendering.
  • Characteristics: Faster than the CLI method because it does not wait for the Argo CD Application controller reconciliation loop. It also provides more detailed error messages when rendering fails, since it surfaces errors directly from the API server. However, it is slightly more fragile because the tool must manage connections and authentication manually.
  • Lockdown mode: Compatible with lockdown mode (namespace-scoped Argo CD).

3. Repo Server API (repo-server-api) - 🧪 Experimental🔗

The repo-server-api method is an experimental fast-path that bypasses the cluster's reconciliation loop entirely.

  • How it works: It connects directly to the Argo CD repo-server component via gRPC, asking it to generate the manifests synchronously.
  • Characteristics: The fastest method available. No cluster-side Application objects are created, and no polling of the reconciliation loop is needed.
  • Lockdown mode: Compatible with lockdown mode (namespace-scoped Argo CD).