Overview of Developer Conventions

Developer Conventions is a set of conventions that enable your workloads to support live-update and debug operations in Tanzu Application Platform (commonly known as TAP).

Prerequisites

• Tanzu CLI Apps plug-in
• Tanzu Dev Tools for VSCode IDE extension.

Features

Enabling Live Updates

Developer Conventions modifies your workload to enable live updates in either of the following situations:

• You deploy a workload by using the Tanzu CLI Apps plug-in and include the flag --live-update=true. For more information about how to deploy a workload with the CLI, see Create or update a workload.
• You deploy a workload by using the Tanzu: Live Update Start option through the Tanzu Developer Tools for VS Code extension. For more information about live updating with the extension, see Overview of Tanzu Developer Tools for Visual Studio Code.

When either of the preceding actions take place, the convention behaves as follows:

1. Looks for the apps.tanzu.vmware.com/live-update=true annotation on a PodTemplateSpec associated with a workload.
2. Verifies that the image to which conventions are applied contains a process that can be live updated.
3. Adds annotations to the PodTemplateSpec to modify the Knative properties minScale & maxScale such that the minimum and maximum number of pods is 1. This ensures the eventual running pod is not scaled down to 0 during a live update session.

After these changes are made, you can use the Tanzu Dev Tools extension or the Tilt CLI to make live update changes to source code directly on the cluster.

Enabling debugging

Developer Conventions modifies your workload to enable debugging in either of the following situations:

• You deploy a workload by using the Tanzu CLI Apps plug-in and include the flag --debug=true. For more information about how to deploy a workload with the CLI, see Create or update a workload.
• You deploy a workload by using the Tanzu Java Debug Start option through the Tanzu Developer Tools for VS Code extension. For more information about debugging with the extension, see Overview of Tanzu Developer Tools for Visual Studio Code.

When either of the preceding actions take place, the convention behaves as follows:

1. It looks for the apps.tanzu.vmware.com/debug=true annotation on a PodTemplateSpec associated with a workload.
2. It checks for the debug-8 or debug-9 labels on the image configuration’s bill of materials (BOM).
3. It sets the TimeoutSeconds of the Liveness, Readiness, and Startup probes to 600 if currently set to a lower number.
4. It adds annotations to the PodTemplateSpec to modify the Knative properties minScale & maxScale such that the minimum and maximum number of pods is 1. This ensures the eventual running pod won’t be scaled down to 0 during a debug session.

After these changes are made, you can use the Tanzu Dev Tools extension or other CLI-based debuggers to debug your workload directly on the cluster.

Note

Currently, Developer Conventions only supports debug operations for Java applications.

Next steps

• Install Developer Conventions