bin/ci: Add GitLab basic token validation

Validate the token to be able to warn the user about wrong
authentication settings.
Treat the default token argument case, when the token file is not found.
Add some loggings to guide the user.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27206>

bin/ci/gitlab_common.py

@@ -8,13 +8,29 @@
 # SPDX-License-Identifier: MIT
 '''Shared functions between the scripts.'''
 
+import logging
 import os
+import re
 import time
 from pathlib import Path
 
 GITLAB_URL = "https://gitlab.freedesktop.org"
 TOKEN_DIR = Path(os.getenv("XDG_CONFIG_HOME") or Path.home() / ".config")
 
+# Known GitLab token prefixes: https://docs.gitlab.com/ee/security/token_overview.html#token-prefixes
+TOKEN_PREFIXES: dict[str, str] = {
+    "Personal access token": "glpat-",
+    "OAuth Application Secret": "gloas-",
+    "Deploy token": "gldt-",
+    "Runner authentication token": "glrt-",
+    "CI/CD Job token": "glcbt-",
+    "Trigger token": "glptt-",
+    "Feed token": "glft-",
+    "Incoming mail token": "glimt-",
+    "GitLab Agent for Kubernetes token": "glagent-",
+    "SCIM Tokens": "glsoat-"
+}
+
 
 def pretty_duration(seconds):
     """Pretty print duration"""
@@ -71,25 +87,61 @@ def get_token_from_default_dir() -> str:
         raise ex
 
 
+def validate_gitlab_token(token: str) -> bool:
+    token_suffix = token.split("-")[-1]
+    # Basic validation of the token suffix based on:
+    # https://gitlab.com/gitlab-org/gitlab/-/blob/master/gems/gitlab-secret_detection/lib/gitleaks.toml
+    if not re.match(r"(\w+-)?[0-9a-zA-Z_\-]{20,64}", token_suffix):
+        raise ValueError("The provided token does not match valid GitLab token format.")
+
+    for token_type, token_prefix in TOKEN_PREFIXES.items():
+        if token.startswith(token_prefix):
+            logging.info(f"Found probable token type: {token_type}")
+            return True
+
+    # If the token type is not recognized, return False
+    return False
+
+
+def get_token_from_arg(token_arg: str | Path | None) -> str | None:
+    if not token_arg:
+        logging.info("No token provided.")
+        return None
+
+    token_path = Path(token_arg)
+    if token_path.is_file():
+        return read_token_from_file(token_path)
+
+    return handle_direct_token(token_path, token_arg)
+
+
+def read_token_from_file(token_path: Path) -> str:
+    token = token_path.read_text().strip()
+    logging.info(f"Token read from file: {token_path}")
+    return token
+
+
+def handle_direct_token(token_path: Path, token_arg: str | Path) -> str | None:
+    if token_path == Path(get_token_from_default_dir()):
+        logging.warning(
+            f"The default token file {token_path} was not found. "
+            "Please provide a token file or a token directly via --token arg."
+        )
+        return None
+    logging.info("Token provided directly as an argument.")
+    return str(token_arg)
+
+
 def read_token(token_arg: str | Path | None) -> str | None:
-    """
-    Reads the token from the given file path or returns the token argument if it is not a file.
-
-    Args:
-        token_arg (str | Path | None): The file path or the token itself.
-
-    Returns:
-        str | None: The token string or None if the token is not provided.
-    """
-    if token_arg:
-        token_path = Path(token_arg)
-        if token_path.is_file():
-            # if is a file, read it
-            return token_path.read_text().strip()
-        return str(token_arg)
-
-    # if the token is not provided neither its file, return None
-    return None
+    token = get_token_from_arg(token_arg)
+    if token and not validate_gitlab_token(token):
+        logging.warning("The provided token is either an old token or does not seem to "
+                        "be a valid token.")
+        logging.warning("Newer tokens are the ones created from a Gitlab 14.5+ instance.")
+        logging.warning("See https://about.gitlab.com/releases/2021/11/22/"
+                        "gitlab-14-5-released/"
+                        "#new-gitlab-access-token-prefix-and-detection")
+    return token
 
 
 def wait_for_pipeline(projects, sha: str, timeout=None):