Terraform modules

To reuse code across different Coder templates, such as common scripts or resource definitions, we suggest using Terraform Modules.

You can store these modules externally from your Coder deployment, like in a git repository or a Terraform registry. This example shows how to reference a module from your template:

data "coder_workspace" "me" {}

module "coder-base" {
  source = "github.com/my-organization/coder-base"

  # Modules take in variables and can provision infrastructure
  vpc_name            = "devex-3"
  subnet_tags         = { "name": data.coder_workspace.me.name }
  code_server_version = 4.14.1
}

resource "coder_agent" "dev" {
  # Modules can provide outputs, such as helper scripts
  startup_script=<<EOF
  #!/bin/sh
  ${module.coder-base.code_server_install_command}
  EOF
}

Learn more about creating modules and module sources in the Terraform documentation.

Git authentication

If you are importing a module from a private git repository, the Coder server or provisioner needs git credentials. Since this token will only be used for cloning your repositories with modules, it is best to create a token with access limited to the repository and no extra permissions. In GitHub, you can generate a fine-grained token with read only access to the necessary repos.

If you are running Coder on a VM, make sure that you have git installed and the coder user has access to the following files:

# /home/coder/.gitconfig
[credential]
  helper = store

# /home/coder/.git-credentials

# GitHub example:
https://your-github-username:[email protected]

If you are running Coder on Docker or Kubernetes, git is pre-installed in the Coder image. However, you still need to mount credentials. This can be done via a Docker volume mount or Kubernetes secrets.

Passing git credentials in Kubernetes

First, create a .gitconfig and .git-credentials file on your local machine. You might want to do this in a temporary directory to avoid conflicting with your own git credentials.

Next, create the secret in Kubernetes. Be sure to do this in the same namespace that Coder is installed in.

export NAMESPACE=coder
kubectl apply -f - <<EOF
apiVersion: v1
kind: Secret
metadata:
  name: git-secrets
  namespace: $NAMESPACE
type: Opaque
data:
  .gitconfig: $(cat .gitconfig | base64 | tr -d '\n')
  .git-credentials: $(cat .git-credentials | base64 | tr -d '\n')
EOF

Then, modify Coder's Helm values to mount the secret.

coder:
  volumes:
    - name: git-secrets
      secret:
        secretName: git-secrets
  volumeMounts:
    - name: git-secrets
      mountPath: "/home/coder/.gitconfig"
      subPath: .gitconfig
      readOnly: true
    - name: git-secrets
      mountPath: "/home/coder/.git-credentials"
      subPath: .git-credentials
      readOnly: true

Artifactory

JFrog Artifactory can serve as a Terraform module registry, allowing you to simplify a Coder-stored template to a module block and input variables.

With this approach, you can:

• Easily share templates across multiple Coder instances
• Store templates far larger than the 1MB limit of Coder's template storage
• Apply JFrog platform security policies to your templates

Basic Scaffolding

For example, a template with:

module "frontend" {
  source = "cdr.jfrog.io/tf__main/frontend/docker"
}

References the frontend module in the main namespace of the tf repository. Remember to replace cdr.jfrog.io with your Artifactory instance URL.

You can upload the underlying module to Artifactory with:

# one-time setup commands
# run this on the coder server (or external provisioners, if you have them)
terraform login cdr.jfrog.io; jf tfc --global

# jf tf p assumes the module name is the same as the current directory name.
jf tf p --namespace=main --provider=docker --tag=v0.0.1

Example template

We have an example template here that uses our JFrog Docker template as the underlying module.

Next up

Learn more about

• JFrog's Terraform Registry support here.
• Configuring the JFrog toolchain inside a workspace here.
• Coder Module Registry here