Add ui server support for proxied artifacts and update exception mess…

…ages

Signed-off-by: Ben Wilson <benjamin.wilson@databricks.com>

mlflow/cli.py

@@ -243,10 +243,13 @@ def _validate_server_args(gunicorn_opts=None, workers=None, waitress_opts=None):
     "Note that this flag does not impact already-created experiments. "
     "Default: " + DEFAULT_LOCAL_FILE_AND_ARTIFACT_PATH,
 )
+@cli_args.SERVE_ARTIFACTS
 @cli_args.ARTIFACTS_DESTINATION
 @cli_args.PORT
 @cli_args.HOST
-def ui(backend_store_uri, default_artifact_root, artifacts_destination, port, host):
+def ui(
+    backend_store_uri, default_artifact_root, serve_artifacts, artifacts_destination, port, host
+):
     """
     Launch the MLflow tracking UI for local viewing of run results. To launch a production
     server, use the "mlflow server" command instead.
@@ -281,7 +284,7 @@ def ui(backend_store_uri, default_artifact_root, artifacts_destination, port, ho
         _run_server(
             backend_store_uri,
             default_artifact_root,
-            False,
+            serve_artifacts,
             False,
             artifacts_destination,
             host,
@@ -328,16 +331,7 @@ def _validate_static_prefix(ctx, param, value):  # pylint: disable=unused-argume
     "Default: Within file store, if a file:/ URI is provided. If a sql backend is"
     " used, then this option is required.",
 )
-@click.option(
-    "--serve-artifacts",
-    is_flag=True,
-    help="If specified, enables serving of artifact uploads, downloads, and list requests "
-    "by routing these requests to the storage location that is specified by "
-    "'--artifact-destination' directly through a proxy. The default location that "
-    "these requests are served from is a local './mlartifacts' directory which can be "
-    "overridden via the '--artifacts-destination' argument. "
-    "Default: False",
-)
+@cli_args.SERVE_ARTIFACTS
 @click.option(
     "--artifacts-only",
     is_flag=True,

mlflow/server/handlers.py

@@ -289,9 +289,9 @@ def wrapper(*args, **kwargs):
         if os.environ.get(ARTIFACTS_ONLY_ENV_VAR):
             return Response(
                 (
-                    "Endpoint disabled due to the mlflow server running in `--artifacts-only` "
-                    "mode. To enable tracking server functionality, run `mlflow server` without "
-                    "`--artifacts-only`"
+                    f"Endpoint: {request.url_rule} disabled due to the mlflow server running "
+                    "in `--artifacts-only` mode. To enable tracking server functionality, run "
+                    "`mlflow server` without `--artifacts-only`"
                 ),
                 503,
             )

mlflow/utils/cli_args.py

@@ -99,3 +99,14 @@
         "artifact root location is http or mlflow-artifacts URI."
     ),
 )
+
+SERVE_ARTIFACTS = click.option(
+    "--serve-artifacts",
+    is_flag=True,
+    help="If specified, enables serving of artifact uploads, downloads, and list requests "
+    "by routing these requests to the storage location that is specified by "
+    "'--artifact-destination' directly through a proxy. The default location that "
+    "these requests are served from is a local './mlartifacts' directory which can be "
+    "overridden via the '--artifacts-destination' argument. "
+    "Default: False",
+)

tests/test_cli.py

@@ -258,8 +258,8 @@ def test_mlflow_tracking_disabled_in_artifacts_only_mode():
     _await_server_up_or_die(port, timeout=10)
     resp = requests.get(f"http://localhost:{port}/api/2.0/mlflow/experiments/list")
     assert (
-        "Endpoint disabled due to the mlflow server running in `--artifacts-only` mode."
-        in resp.text
+        "Endpoint: /api/2.0/mlflow/experiments/list disabled due to the mlflow server running "
+        "in `--artifacts-only` mode." in resp.text
     )
     process.kill()