Clarify Docker dependency status inside containers

* fix: show docker as N/A inside the container

* test: cover in-container docker detection

* fix: make the N/A dependency chip legible

* refactor: make remote docker applicability explicit and tested

routes/shell_routes.py

@@ -9,6 +9,7 @@ import shutil
 import subprocess
 import uuid
 import tempfile
+from collections import namedtuple
 from pathlib import Path
 from typing import Dict, Any
 
@@ -61,6 +62,36 @@ logger = logging.getLogger(__name__)
 PTY_SUPPORTED = pty is not None and fcntl is not None and hasattr(os, "setsid")
 
 
+DOCKER_IN_CONTAINER_HINT = (
+    "Not available inside the Odysseus container by design. The image ships no "
+    "docker CLI and no host socket is mounted. Run Docker-backed launches on a "
+    "remote server, where docker is checked over SSH. Mounting /var/run/docker.sock "
+    "into the container would grant it host-root access, so only do that if you "
+    "accept that risk."
+)
+
+
+def _running_in_container(dockerenv_path="/.dockerenv", cgroup_path="/proc/1/cgroup"):
+    if os.path.exists(dockerenv_path):
+        return True
+    try:
+        with open(cgroup_path, "r", encoding="utf-8") as fh:
+            contents = fh.read()
+    except OSError:
+        return False
+    return any(token in contents for token in ("docker", "containerd", "kubepods"))
+
+
+DockerRowStatus = namedtuple("DockerRowStatus", ["applicable", "install_hint"])
+
+
+def _docker_row_status(*, on_remote, in_container, installed, default_hint):
+    local_docker_unavailable = not on_remote and in_container and not installed
+    if local_docker_unavailable:
+        return DockerRowStatus(applicable=False, install_hint=DOCKER_IN_CONTAINER_HINT)
+    return DockerRowStatus(applicable=True, install_hint=default_hint)
+
+
 def _find_line_break(buf):
     """Find next line terminator in buffer. Returns (index, separator_length) or (-1, 0)."""
     ni = buf.find(b"\n")
@@ -702,20 +733,29 @@ def setup_shell_routes() -> APIRouter:
                 pass
 
         for pkg in packages:
-            if host and pkg.get("target") == "remote":
+            on_remote = bool(host and pkg.get("target") == "remote")
+            if on_remote:
                 pkg["installed"] = bool(remote_status.get(pkg["name"], False))
-                continue
-            if pkg.get("kind") == "system":
+            elif pkg.get("kind") == "system":
                 pkg["installed"] = shutil.which(pkg["name"]) is not None
-                continue
-            try:
-                if pkg["name"] == "llama_cpp" and shutil.which("llama-server"):
-                    pkg["installed"] = True
-                    continue
-                importlib.import_module(pkg["name"])
+            elif pkg["name"] == "llama_cpp" and shutil.which("llama-server"):
                 pkg["installed"] = True
-            except ImportError:
-                pkg["installed"] = False
+            else:
+                try:
+                    importlib.import_module(pkg["name"])
+                    pkg["installed"] = True
+                except ImportError:
+                    pkg["installed"] = False
+
+            if pkg["name"] == "docker":
+                status = _docker_row_status(
+                    on_remote=on_remote,
+                    in_container=_running_in_container() if not on_remote else False,
+                    installed=pkg["installed"],
+                    default_hint=pkg.get("install_hint"),
+                )
+                pkg["applicable"] = status.applicable
+                pkg["install_hint"] = status.install_hint
         return {"packages": packages}
 
     @router.post("/api/cookbook/packages/install")