Fix Docker client installation on Debian 13

agent/tests/test_installer.py

@@ -20,6 +20,7 @@ PREFLIGHT = next(block for block in BLOCKS if "# INSTALLATION_PREFLIGHT:" in blo
 OWNERSHIP = next(block for block in BLOCKS if "# INSTALLATION_OWNERSHIP:" in block)
 RELEASE = next(block for block in BLOCKS if "# INSTALLATION_RELEASE:" in block)
 CLEANUP = re.search(r"installation_cleanup\(\) \{.*?\n\}", SOURCE, re.DOTALL).group()
+DOCKER = SOURCE[SOURCE.index("# INSTALLATION_DOCKER:"):SOURCE.index("install -d -m 0700 /etc/electric-cherry")]
 SPEC = importlib.util.spec_from_file_location("package_release", Path(__file__).resolve().parents[1] / "package_release.py")
 PACKAGER = importlib.util.module_from_spec(SPEC)
 SPEC.loader.exec_module(PACKAGER)
@@ -230,6 +231,109 @@ class InstallerTests(unittest.TestCase):
                         self.preflight()
 
 
+class DockerInstallerTests(unittest.TestCase):
+    def run_docker_setup(self, version="13", cli=False, engine=False, available=True,
+                         data=False, config=False, apt_status=0, supply_cli=True):
+        with tempfile.TemporaryDirectory() as temporary:
+            base = Path(temporary)
+            docker_data = base / "docker-data"
+            docker_config = base / "daemon.json"
+            if data:
+                docker_data.mkdir()
+                (docker_data / "sentinel").write_text("existing containers")
+            if config:
+                docker_config.write_text("existing configuration")
+            block = DOCKER.replace("/var/lib/docker", str(docker_data)).replace("/etc/docker/daemon.json", str(docker_config))
+            # Simulate Debian's package split and Docker state. All commands that
+            # could install packages or touch services are shell stubs.
+            script = r'''
+set -euo pipefail
+command() { [ "$*" = '-v docker' ] && [ "$EC_TEST_CLI" = true ]; }
+dpkg-query() {
+    [ "$*" = '-W -f=${Status} docker.io' ] || exit 90
+    [ "$EC_TEST_ENGINE" = true ] || return 1
+    printf 'install ok installed'
+}
+apt-get() {
+    printf 'apt-get %s\n' "$*"
+    [ "$EC_TEST_APT_STATUS" = 0 ] || return "$EC_TEST_APT_STATUS"
+    if [ "$EC_TEST_SUPPLY_CLI" = true ]; then
+        case " $* " in
+            *' docker-cli '*) EC_TEST_CLI=true ;;
+            *' docker.io '*) if [ "$VERSION_ID" = 12 ]; then EC_TEST_CLI=true; fi ;;
+        esac
+    fi
+}
+systemctl() { printf 'systemctl %s\n' "$*"; }
+docker() {
+    [ "$EC_TEST_CLI" = true ] || return 127
+    [ "$*" = info ] || exit 91
+    if [ "$EC_TEST_AVAILABLE" != true ]; then
+        echo 'Cannot connect to the Docker daemon' >&2
+        return 1
+    fi
+}
+'''
+            environment = {**os.environ, "VERSION_ID": version,
+                           "EC_TEST_CLI": str(cli).lower(), "EC_TEST_ENGINE": str(engine).lower(),
+                           "EC_TEST_AVAILABLE": str(available).lower(), "EC_TEST_APT_STATUS": str(apt_status),
+                           "EC_TEST_SUPPLY_CLI": str(supply_cli).lower()}
+            result = subprocess.run(["bash", "-c", script + block], env=environment, capture_output=True, text=True)
+            if data:
+                self.assertEqual((docker_data / "sentinel").read_text(), "existing containers")
+            if config:
+                self.assertEqual(docker_config.read_text(), "existing configuration")
+            return result
+
+    def test_fresh_debian_12_and_13_install_both_engine_and_client(self):
+        for version, packages in (("12", "docker.io"), ("13", "docker.io docker-cli")):
+            with self.subTest(version=version):
+                result = self.run_docker_setup(version=version)
+                self.assertEqual(result.returncode, 0, result.stderr)
+                self.assertEqual(result.stdout.splitlines(), [
+                    f"apt-get install -y --no-install-recommends {packages}",
+                    "systemctl enable --now docker"])
+
+    def test_rerun_repairs_debian_13_missing_client_without_touching_engine(self):
+        result = self.run_docker_setup(engine=True, data=True, config=True)
+        self.assertEqual(result.returncode, 0, result.stderr)
+        self.assertEqual(result.stdout.splitlines(), [
+            "apt-get install -y --no-install-recommends --no-remove docker-cli"])
+
+    def test_existing_docker_including_ce_is_reused_without_package_or_service_changes(self):
+        for engine in (False, True):
+            with self.subTest(debian_engine=engine):
+                result = self.run_docker_setup(cli=True, engine=engine, data=True, config=True)
+                self.assertEqual(result.returncode, 0, result.stderr)
+                self.assertEqual(result.stdout, "")
+
+    def test_unknown_existing_data_or_configuration_still_blocks_engine_installation(self):
+        for data, config in ((True, False), (False, True)):
+            with self.subTest(data=data, config=config):
+                result = self.run_docker_setup(data=data, config=config)
+                self.assertNotEqual(result.returncode, 0)
+                self.assertIn("Existing Docker data/configuration", result.stderr)
+                self.assertEqual(result.stdout, "")
+
+    def test_unavailable_existing_engine_exposes_docker_error_without_restarting_it(self):
+        result = self.run_docker_setup(cli=True, available=False)
+        self.assertNotEqual(result.returncode, 0)
+        self.assertIn("Cannot connect to the Docker daemon", result.stderr)
+        self.assertIn("journalctl -u docker", result.stderr)
+        self.assertEqual(result.stdout, "")
+
+    def test_package_failure_stops_before_starting_docker(self):
+        result = self.run_docker_setup(apt_status=42)
+        self.assertEqual(result.returncode, 42)
+        self.assertNotIn("systemctl", result.stdout)
+
+    def test_missing_client_is_distinguished_from_an_unavailable_daemon(self):
+        result = self.run_docker_setup(supply_cli=False)
+        self.assertNotEqual(result.returncode, 0)
+        self.assertIn("Docker CLI is missing", result.stderr)
+        self.assertNotIn("Docker is installed but unavailable", result.stderr)
+
+
 class ReleaseTests(unittest.TestCase):
     def setUp(self):
         self.temporary = tempfile.TemporaryDirectory()