DEVELOPMENT.md

Developer Guide

Packer runs 3rd party plugins as subprocesses, and communicates with them over RPC via stdin/stdout. The packer libraries handle all of the low level details, so we just need to implement interfaces to do CUE evaluation on the user's workstation.

Testing Your Binary

Running make drops a binary in the root of this repo.

There are two steps to make Packer use your development version of this plugin.

1. Copy the built binary to a suitable place on disk
2. Comment out any official released version from required_plugins in your HCL

This plugin is a "multi-component" plugin. Consult the manual installation procedure for more details. You will need to move the binary to a location Packer can find it. The easiest thing to do is to move the binary to the directory where you invoke packer.

For example, if you want to run a build in the "examples" folder, copy packer-plugin-cue there.

For step 2, simply make sure there is no reference to "github.com/dontlaugh/cue" in your required_plugins config.

packer {
  required_plugins {
     lxd = {
       version = ">=1.0.0"
       source  = "github.com/hashicorp/lxd"
     }
-    cue = {
-      version = ">=0.3.1"
-      source = "github.com/dontlaugh/cue"
-    }
+    // cue = {
+    //  version = ">=0.3.1"
+    //  source = "github.com/dontlaugh/cue"
+    // }
   }
 }

The custom cue-export provisioner will still work.

Debug Logging

Set PACKER_LOG=1 in your environment for extra logging. This log output will also indicate whether Packer has located your custom built plugin.

HCL Config Codegen

If you make a change to a config struct, you need to regenerate some files.

make generate

Regarding zlconf/go-cty

We cannot upgrade this dependency until this issue is resolved

• hashicorp/packer-plugin-sdk#128