Fix race condition if a workflow job gets canceled before the runner VM accepted the job leading to an idling VM, always default to latest GitHub runner release if 'github_runner_download_url' is left empty

Author: Tereius

README.md

@@ -149,12 +149,13 @@ Error applying IAM policy for cloudrun service "v1/projects/github-spot-runner/l
 
 2. Solution: Override the Organization Policy "Domain Restricted Sharing" in the project, by setting it to "Allow all".
 
-#### The VM Instance immediately stops after it was created without processing a workflow job
+#### The VM instance stops shortly after it was created without processing a workflow task
 
-The VM will shoutdown itself if the registration at the GitHub runner group fails. This can be caused by:
-* An invalid jit-config.
+The VM will stop itself if the registration at the GitHub runner group fails. This can be caused by:
 * A typo in the GitHub Enterprise, Organization, Repository name. Check the Terraform variables `github_enterprise`, `github_organization`, `github_repositories` for typos.
 * A not existing GitHub runner group within the Enterprise/Organization. Check the Terraform variable `github_runner_group` for typos.
+* The GitHub runner version is [deprecated](https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners/autoscaling-with-self-hosted-runners#controlling-runner-software-updates-on-self-hosted-runners). The GitHub runner won't accept any Workflow job. Check the Terraform variable `github_runner_download_url` and update to latest GitHub runner version.
+* An invalid jit-config.
 
 You can observer the runner registration process by connecting to the VM instance via SSH and running:
 ```

compute.tf

@@ -86,7 +86,13 @@ apt-get update && apt-get -y install docker.io docker-buildx curl jq ${local.git
 useradd -d /home/agent -u ${var.github_runner_uid} agent
 usermod -aG docker agent
 newgrp docker
-curl -s -o /tmp/agent.tar.gz -L '${var.github_runner_download_url}'
+RUNNER_DOWNLOAD_URL='${var.github_runner_download_url}'
+if [ -z "$${RUNNER_DOWNLOAD_URL}" ]; then
+  RUNNER_VERSION=$(curl -s "https://github.com/actions/runner/tags/" | grep -Eo "$Version v[0-9]+.[0-9]+.[0-9]+" | sort -r | head -n1 | tr -d ' ' | tr -d 'v')
+  echo "Downloading latest runner v$${RUNNER_VERSION}"
+  RUNNER_DOWNLOAD_URL="https://github.com/actions/runner/releases/download/v$${RUNNER_VERSION}/actions-runner-linux-x64-$${RUNNER_VERSION}.tar.gz"
+fi
+curl -s -o /tmp/agent.tar.gz -L $${RUNNER_DOWNLOAD_URL}
 mkdir -p /home/agent
 chown -R agent:agent /home/agent
 pushd /home/agent
@@ -95,14 +101,17 @@ encoded_jit_config=$1
 echo -n $encoded_jit_config | base64 -d | jq '.".runner"' -r | base64 -d > .runner
 echo -n $encoded_jit_config | base64 -d | jq '.".credentials"' -r | base64 -d > .credentials
 echo -n $encoded_jit_config | base64 -d | jq '.".credentials_rsaparams"' -r | base64 -d > .credentials_rsaparams
-sed -i 's/{{SvcNameVar}}/actions.runner.${var.github_organization}.$${agent_name}.service/g' bin/systemd.svc.sh.template
-sed -i 's/{{SvcDescription}}/GitHub Actions Runner (${var.github_organization}.$${agent_name})/g' bin/systemd.svc.sh.template
+sed -i 's/{{SvcNameVar}}/actions.runner.service/g' bin/systemd.svc.sh.template
+sed -i 's/{{SvcDescription}}/GitHub Actions Runner/g' bin/systemd.svc.sh.template
 cp bin/systemd.svc.sh.template ./svc.sh && chmod +x ./svc.sh
 ./bin/installdependencies.sh || shutdown now
 ./svc.sh install agent || shutdown now
 ./svc.sh start || shutdown now
 popd
 rm /tmp/agent.tar.gz
-echo "Setup finished"
+echo "Setup finished - waiting for Workflow Job"
+sleep 60
+journalctl -u actions.runner.service -o json --no-pager | jq -e '.|.MESSAGE|match("Running job:")' || shutdown now
+echo "Accepted Workflow Job - processing"
 EOT
 }

variables.tf

@@ -94,8 +94,8 @@ variable "github_runner_prefix" {
 
 variable "github_runner_download_url" {
   type        = string
-  description = "The download link pointing to the gitlab runner package"
-  default     = "https://github.com/actions/runner/releases/download/v2.321.0/actions-runner-linux-x64-2.321.0.tar.gz"
+  description = "A download link pointing to the gitlab runner package (WARNING: deprecated runner versions won't process jobs). If this variable is empty (by default), the latest runner release will be downloaded."
+  default     = ""
 }
 
 variable "github_runner_uid" {