feat(kosync): add Terraform module for KOReader sync server

quadlets/modules/kosync/main.tf

@@ -0,0 +1,61 @@
+variable "wait_on" {
+  type        = any
+  description = "Resources to wait on"
+  default     = true
+}
+
+variable "server_ip" {
+  type = string
+}
+
+variable "ssh_private_key_path" {
+  type = string
+}
+
+variable "server_domain" {
+  type = string
+}
+
+module "kosync" {
+  source  = "../quadlet-app"
+  wait_on = var.wait_on
+
+  server_ip            = var.server_ip
+  ssh_private_key_path = var.ssh_private_key_path
+
+  app_name = "kosync"
+  image    = "docker.io/koreader/kosync:latest"
+  ports    = ["17200:17200"]
+  volumes = [
+    "/opt/storage/data/kosync/logs/app:/app/koreader-sync-server/logs:Z",
+    "/opt/storage/data/kosync/logs/redis:/var/log/redis:Z",
+    "/opt/storage/data/kosync/data/redis:/var/lib/redis:Z",
+  ]
+
+  environment = {
+    ENABLE_USER_REGISTRATION = "true"
+    GIN_ENV                  = "production"
+  }
+
+  # Healthcheck over plain HTTP (port 17200) since HAProxy handles TLS
+  healthcmd = "curl -sf -H \"Accept: application/vnd.koreader.v1+json\" http://127.0.0.1:17200/healthcheck | grep -q '\"state\":\"OK\"'"
+
+  haproxy_services = [
+    {
+      name   = "kosync"
+      domain = "kosync.${var.server_domain}"
+      port   = "17200"
+      host   = "127.0.0.1"
+      tls    = false
+    },
+  ]
+}
+
+output "app_urls" {
+  value = module.kosync.app_urls
+}
+
+output "installed" {
+  value      = true
+  depends_on = [module.kosync.installed]
+}