feat: Added the ability to spin-up an abritrary number of runners at runtime

infra/modules/dev/main.tf

@@ -88,4 +88,19 @@ resource "hcloud_volume" "storage" {
   server_id = hcloud_server.this.id
   automount = true
   format    = "ext4"
+
+  lifecycle {
+    prevent_destroy = true
+  }
+}
+
+# Renders services/dev/Runners/docker-compose.yml directly into the repo, with
+# one runner service per var.runner_count. This only touches the local working
+# tree - deploying the change still goes through the normal scp + spinup.sh flow.
+resource "local_file" "runners_compose" {
+  filename = "${path.root}/../services/dev/Runners/docker-compose.yml"
+  content = templatefile("${path.module}/templates/runners-docker-compose.yml.tftpl", {
+    runner_count = var.runner_count
+  })
+  file_permission = "0644"
 }

infra/modules/dev/templates/runners-docker-compose.yml.tftpl

@@ -0,0 +1,30 @@
+# Generated by OpenTofu from var.dev_runner_count - do not hand-edit.
+# To change the number of runners, edit dev_runner_count in terraform.tfvars and
+# run tofu apply. To change their shape, edit
+# infra/modules/dev/templates/runners-docker-compose.yml.tftpl instead.
+#
+# GITEA_RUNNER_REGISTRATION_TOKEN is intentionally left as a compose variable
+# (not baked in here) - services/dev/spinup.sh generates a fresh token and
+# writes it to Runners/.env immediately before starting these containers.
+services:
+%{ for i in range(runner_count) ~}
+  runner-${i + 1}:
+    image: gitea/act_runner:latest
+    container_name: gitea_runner_${i + 1}
+    volumes:
+      - ./config.yaml:/config.yaml
+      - ./gitea_runner_${i + 1}:/data
+      - /var/run/docker.sock:/var/run/docker.sock
+    networks:
+      - proxy
+    environment:
+      CONFIG_FILE: /config.yaml
+      GITEA_INSTANCE_URL: "https://git.luke-else.co.uk"
+      GITEA_RUNNER_REGISTRATION_TOKEN: "$${GITEA_RUNNER_REGISTRATION_TOKEN}"
+      GITEA_RUNNER_NAME: "CICD#${i + 1}"
+    restart: unless-stopped
+%{ endfor ~}
+
+networks:
+  proxy:
+    external: true

infra/modules/dev/variables.tf

@@ -52,3 +52,8 @@ variable "ssh_private_key_path" {
   description = "Local path to the private key matching var.ssh_key_id, used to run the bootstrap script over SSH."
   type        = string
 }
+
+variable "runner_count" {
+  description = "Number of Gitea Actions runner containers to render into services/dev/Runners/docker-compose.yml."
+  type        = number
+}

infra/modules/prod/main.tf

@@ -115,4 +115,8 @@ resource "hcloud_volume" "storage" {
   server_id = hcloud_server.this.id
   automount = true
   format    = "ext4"
+
+  lifecycle {
+    prevent_destroy = true
+  }
 }