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

infra/.terraform.lock.hcl

@@ -33,6 +33,43 @@ provider "registry.opentofu.org/hashicorp/hcloud" {
   ]
 }
 
+provider "registry.opentofu.org/hashicorp/local" {
+  version     = "2.9.0"
+  constraints = "~> 2.5"
+  hashes = [
+    "h1:1dtKYW/5a1qob3yneL6WzOlnSGfYtJ6a2XeejCk9yb4=",
+    "h1:5NseXq5wU8O20ersTtV4ocrLYFFtgFr7n0pRLO1W2Rw=",
+    "h1:5d22ZPPK4iiygPbwRz/PJF5Es/0axVpMlPRpCR0Padw=",
+    "h1:AnwyolirmIlBMjH6+tV8bKkvT+5axJNYxi2y2IguiX4=",
+    "h1:PBp+HeseY021Fw3sLznCG27idgwPoff4cBuNmKgPL2w=",
+    "h1:VDxIhe4GbzdOCdmt7mQaqdwERQW6GSI7Roonts42Gr0=",
+    "h1:ZO6eWWnf8LjjV1q/JNeL9WLtZ6fwIttOnyN5LjCNSEo=",
+    "h1:dPIAf8oUAz+vW2E0iZunMvpuPddRZIztRsPSY1u+VnY=",
+    "h1:fwTDVG9AhFVKQZIb1EXkHv4FqzsZNlLWgkyPGDmZZEE=",
+    "h1:kDc465XPC7/6XFCjrMC4mTqhA9ef0FHKuJ3ZgfGNfeg=",
+    "h1:kGbjxrI2P8MHeyVtE1U3Q1TbyF71ExnHxtkrE+Aj6UU=",
+    "h1:kcoK6Afbsj54u9zaEqpecWAFKytqjBijtguCNwV3d4M=",
+    "h1:rxomJjDwOo+YZ+WIPc25FqEgsz9orh/2MCyUcZmFjvw=",
+    "h1:t0CMn/Rkwquw8l2yQ+O4ApzbMZfY2UazbsDnZygzACA=",
+    "h1:tJwgm2BS4xCGlElCDQEFXQoefY9Y4t0JdSKTtsPBbBo=",
+    "zh:13ef7ecd1e397ec5b20ea588508dd3e3b8d6c50d809ae76b079abf9dd8d02e4b",
+    "zh:2190c9325980076489ce02b0f5dd2c0b91fc8711cefa99e714d8619a32827ad1",
+    "zh:2a0cfc5600730093705071707e4a4e4e953e7d9091859e0f66b46daa1060dd5d",
+    "zh:2ff53eac1af43ab9a2248a0e53c963d46e19cf04bc4c3f323591cfcebb218252",
+    "zh:4ebc3dee700f60af9da29970052fd02fa947813162b224716862dc9d7f1f7542",
+    "zh:5fe6dab84ceeaa8eb3f1567c5f05578333370c472240ca5c5bfc25e92d4d5586",
+    "zh:66bbec16367bbf440045502c9779b11f4ac5b022c8d8d17afe12d431950838b5",
+    "zh:7641e5c2e4b529e869cde29ab5b1de2fd1091489eb745b19ac2709bd7f4dfd84",
+    "zh:855bfba0756d17ce07595ff57d7cf664443d1495127cb88fb063362734b8b22a",
+    "zh:aaec10f237921d60c581d1b7a66f0a8a8019d9802dc04af11b5b981f6682e01d",
+    "zh:e460835a38ffa1e74f6929904bfd14ef473d217fd537b7ce834abe5ce5e2ce07",
+    "zh:ecc4295215db0e4aea3c9329611c31e09a853e1ae207d56742403bd4f5516703",
+    "zh:ee6d9fae63a612072e00402894e14826af7a3351c235b9c5b423b7629a77ca29",
+    "zh:f2b5c8db74aa7ebcf7cd423672358437d42401675069ef67b01ff910054e49d5",
+    "zh:f5aff74d3eb96d4592c7bca5cd3ea89b469e84efbf382944bd0f844a57059c09",
+  ]
+}
+
 provider "registry.opentofu.org/hetznercloud/hcloud" {
   version     = "1.66.0"
   constraints = "~> 1.45"

infra/main.tf

@@ -38,6 +38,7 @@ module "dev" {
   network_ip_range       = var.network_ip_range
   bootstrap_script       = local.bootstrap_script
   ssh_private_key_path   = var.ssh_private_key_path
+  runner_count           = var.dev_runner_count
 
   # module.network.id alone doesn't guarantee the subnet exists yet, and a server
   # can't join a network before it has a subnet.

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
+  }
 }

infra/terraform.tfvars.example

@@ -22,3 +22,4 @@ ssh_private_key_path = "~/.ssh/id_ed25519"
 # prod_volume_size       = 20
 # allowed_ssh_source_ips = ["203.0.113.4/32"]
 # deploy_user             = "deploy"
+# dev_runner_count       = 3

infra/variables.tf

@@ -91,3 +91,9 @@ variable "deploy_user" {
   type        = string
   default     = "deploy"
 }
+
+variable "dev_runner_count" {
+  description = "Number of Gitea Actions runner containers to run on dev. Rendered into services/dev/Runners/docker-compose.yml on every tofu apply - see infra/modules/dev/templates/runners-docker-compose.yml.tftpl."
+  type        = number
+  default     = 1
+}

infra/versions.tf

@@ -6,6 +6,10 @@ terraform {
       source  = "hetznercloud/hcloud"
       version = "~> 1.45"
     }
+    local = {
+      source  = "hashicorp/local"
+      version = "~> 2.5"
+    }
   }
 }