feat: enforce per-container memory/CPU limits

CONTAINER_MEMORY_MB and CONTAINER_CPUS (defaults 512/1) are now applied
to every installed MCP container's HostConfig instead of leaving them
unbounded.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.env.example

@@ -24,3 +24,7 @@ SESSION_SECRET=change-me-too
 # Random string (min 32 chars) used to derive the AES-256-GCM key that encrypts
 # installation env vars and bearer tokens at rest
 MASTER_KEY=change-me-to-a-random-string-of-at-least-32-characters
+
+# Resource caps applied to every installed MCP container (same limit for all, no per-installation override in V1)
+CONTAINER_MEMORY_MB=512
+CONTAINER_CPUS=1

README.md

@@ -31,10 +31,27 @@ the manager itself must run as a container attached to `mcp-net` to reach the MC
 containers it manages — running it directly on the host only works for routes that
 don't need to reach a sibling container (e.g. `/health`, `/api/auth`).
 
+## Tests
+
+```sh
+npm test
+```
+
+Runs the `apps/server` unit test suite (vitest): the secrets encryption round-trip, the
+Nixpacks runtime-version detection, the admin-session middleware, and the installations
+state machine against a temporary SQLite DB. `.gitea/workflows/ci.yml` runs the same build
+and test steps on every push, provided this repo's Gitea instance has Actions enabled with
+a runner.
+
 ## Known limitations
 
 - Nixpacks needs a dependency manifest (`requirements.txt`/`pyproject.toml` for Python,
   `package.json` for Node) in the installed repo. Repos without one will fail to build;
   the full build log is always visible in the UI to diagnose this.
-- No per-container resource limits, image garbage collection, or multi-user support yet.
+- Every installed container gets the same memory/CPU caps (`CONTAINER_MEMORY_MB`,
+  `CONTAINER_CPUS`), no per-installation override yet.
+- No multi-user support — single operator only.
 - Builds run one at a time.
+
+See `LESSONS.md` for operational gotchas found while building and running this (Nixpacks
+runtime-version mismatches, Podman networking, SELinux, etc.).

apps/server/src/config/env.ts

@@ -14,4 +14,7 @@ export const config = {
   publicBaseUrl: process.env.PUBLIC_BASE_URL ?? `http://localhost:${process.env.PORT ?? 3000}`,
   adminPassword: process.env.ADMIN_PASSWORD,
   sessionSecret: process.env.SESSION_SECRET,
+  // Per-container resource caps, applied to every installation (no per-installation override in V1).
+  containerMemoryMb: Number(process.env.CONTAINER_MEMORY_MB ?? 512),
+  containerCpus: Number(process.env.CONTAINER_CPUS ?? 1),
 };

apps/server/src/docker/containers.ts

@@ -39,6 +39,8 @@ export async function runInstallationContainer(installation: Installation): Prom
     HostConfig: {
       RestartPolicy: { Name: "unless-stopped" },
       NetworkMode: config.mcpNetworkName,
+      Memory: config.containerMemoryMb * 1024 * 1024,
+      NanoCpus: Math.round(config.containerCpus * 1e9),
     },
   });
 
@@ -46,6 +48,24 @@ export async function runInstallationContainer(installation: Installation): Prom
   return container.id;
 }
 
+export async function getImageId(imageTag: string): Promise<string | undefined> {
+  try {
+    const info = await docker.getImage(imageTag).inspect();
+    return info.Id;
+  } catch {
+    return undefined;
+  }
+}
+
+/** Best-effort removal: leaves the image alone if it's still referenced (e.g. by a running container). */
+export async function removeImageIfUnused(imageId: string): Promise<void> {
+  try {
+    await docker.getImage(imageId).remove({ force: false });
+  } catch {
+    // still in use or already gone — nothing to do
+  }
+}
+
 export async function stopInstallationContainer(containerName: string): Promise<void> {
   await removeContainerIfExists(containerName);
 }

docker-compose.yml

@@ -13,6 +13,8 @@ services:
       ADMIN_PASSWORD: ${ADMIN_PASSWORD}
       SESSION_SECRET: ${SESSION_SECRET}
       MASTER_KEY: ${MASTER_KEY}
+      CONTAINER_MEMORY_MB: ${CONTAINER_MEMORY_MB:-512}
+      CONTAINER_CPUS: ${CONTAINER_CPUS:-1}
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
       - ./data:/repo/data