Add Docker registry UI and tag cleanup automation

Deploy joxit/docker-registry-ui on port 8080 for browsing images/tags.
Add Python script to prune old registry tags (keeps last N per image),
scheduled daily at 2am via cron. Expose UI via reverse proxy at
registry.viktorbarzin.me with Authentik auth.

main.tf

@@ -276,6 +276,12 @@ module "docker-registry-template" {
         templatefile("${path.root}/modules/docker-registry/nginx_registry.conf", {})
       )
     ),
+    "docker run -d --restart always --net host --name registry-ui -e NGINX_LISTEN_PORT=8080 -e NGINX_PROXY_PASS_URL=http://127.0.0.1:5000 -e DELETE_IMAGES=true -e SINGLE_REGISTRY=true -e SHOW_CONTENT_DIGEST=true -e SHOW_CATALOG_NB_TAGS=true -e CATALOG_ELEMENTS_LIMIT=1000 -e TAGLIST_PAGE_SIZE=100 -e REGISTRY_TITLE=viktorbarzin.me joxit/docker-registry-ui:latest",
+    # Deploy tag cleanup script (keep last 10 tags per image) and schedule daily at 2am before weekly GC
+    format("echo %s | base64 -d > /etc/docker-registry/cleanup-tags.sh && chmod +x /etc/docker-registry/cleanup-tags.sh",
+      base64encode(file("${path.root}/modules/docker-registry/cleanup-tags.sh"))
+    ),
+    "( crontab -l 2>/dev/null; echo '0 2 * * * /etc/docker-registry/cleanup-tags.sh 10 >> /var/log/registry-cleanup.log 2>&1' ) | crontab -",
   ]
 }
 
@@ -298,7 +304,8 @@ module "docker-registry-vm" {
   # ports:
   # 5000 -> registry
   # 5001 -> metrics
-  # 5002 -> ngin proxy <-- use this to prevent races on the same blobs
+  # 5002 -> nginx proxy <-- use this to prevent races on the same blobs
+  # 8080 -> registry-ui (joxit/docker-registry-ui)
 }
 
 # module that provisions the proxmox host?

modules/docker-registry/cleanup-tags.sh

@@ -0,0 +1,72 @@
+#!/usr/bin/env python3
+"""Keeps only the N most recent tags per image in a Docker registry.
+Uses filesystem modification times on the tag directories for speed.
+Run garbage-collect after this to reclaim disk space."""
+
+import json
+import os
+import sys
+import urllib.request
+
+sys.stdout.reconfigure(line_buffering=True)
+
+REGISTRY = "http://127.0.0.1:5000"
+KEEP = int(sys.argv[1]) if len(sys.argv) > 1 else 10
+
+# Registry storage path (docker volume)
+STORAGE = "/var/lib/docker/volumes/57b3f1c5fcc7f39c040e17072e10b4536245357d09340206683c04096d30b942/_data/docker/registry/v2/repositories"
+
+def api(path, method="GET", headers=None):
+    req = urllib.request.Request(f"{REGISTRY}{path}", method=method, headers=headers or {})
+    try:
+        with urllib.request.urlopen(req, timeout=30) as r:
+            if method == "HEAD":
+                return dict(r.headers)
+            return json.loads(r.read())
+    except Exception:
+        return None
+
+# Get all repos
+catalog = api("/v2/_catalog")
+if not catalog:
+    print("Failed to fetch catalog")
+    sys.exit(1)
+
+total_deleted = 0
+
+for repo in catalog.get("repositories", []):
+    tags_dir = os.path.join(STORAGE, repo, "_manifests", "tags")
+    if not os.path.isdir(tags_dir):
+        continue
+
+    # Get tags with their modification times from filesystem
+    tag_times = []
+    for tag in os.listdir(tags_dir):
+        tag_path = os.path.join(tags_dir, tag)
+        if os.path.isdir(tag_path):
+            mtime = os.path.getmtime(tag_path)
+            tag_times.append((mtime, tag))
+
+    if len(tag_times) <= KEEP:
+        continue
+
+    # Sort by mtime descending (newest first), delete everything past KEEP
+    tag_times.sort(reverse=True)
+    to_delete = tag_times[KEEP:]
+
+    print(f"[{repo}] has {len(tag_times)} tags, deleting {len(to_delete)}, keeping {KEEP}")
+
+    for _, tag in to_delete:
+        headers_resp = api(f"/v2/{repo}/manifests/{tag}", method="HEAD", headers={
+            "Accept": "application/vnd.docker.distribution.manifest.v2+json"
+        })
+        if not headers_resp:
+            continue
+        digest = headers_resp.get("Docker-Content-Digest") or headers_resp.get("docker-content-digest")
+        if digest:
+            result = api(f"/v2/{repo}/manifests/{digest}", method="DELETE")
+            total_deleted += 1
+
+    print(f"  deleted {len(to_delete)} tags")
+
+print(f"\nDone. Deleted {total_deleted} total tags. Run garbage-collect to reclaim disk space.")

modules/kubernetes/reverse_proxy/main.tf

@@ -151,6 +151,20 @@ module "proxmox" {
   rybbit_site_id   = "190a7ad3e1c7"
 }
 
+# https://registry.viktorbarzin.me/
+module "docker-registry-ui" {
+  source          = "./factory"
+  name            = "registry"
+  external_name   = "docker-registry.viktorbarzin.lan"
+  port            = 8080
+  tls_secret_name = var.tls_secret_name
+  depends_on      = [kubernetes_namespace.reverse-proxy]
+  extra_annotations = {
+    # Override middleware chain to remove rate-limit; the UI fires many API calls to list repos/tags
+    "traefik.ingress.kubernetes.io/router.middlewares" = "traefik-csp-headers@kubernetescrd,traefik-crowdsec@kubernetescrd,traefik-authentik-forward-auth@kubernetescrd"
+  }
+}
+
 # https://valchedrym.viktorbarzin.me/
 module "valchedrym" {
   source           = "./factory"