build_client.get_artifact_content_zip() raises "The user '' is not authorized

I opened the issue originally at https://developercommunity.visualstudio.com/content/problem/917755/get-artifact-content-zip-always-returns-authorizat.html

I got "TF400813: The user '' is not authorized to access this resource.", when using build_client.get_artifact_content_zip()

I did find that I can only reproduce it on certain artifacts, not all of them. My suspicion is that for artifacts whose downloadUrl points to some other host, the credential doesn't transfer correctly.

Here's the code:

import argparse
import pathlib
import sys
import tempfile
import zipfile

import azure.devops.connection as azdo_connection
import msrest

# NOTE, please run this with python >= 3.6, in venv that has these reqs:
# * azure-devops~=5.1.0b3
# * msrest~=0.6.9


def parser():
    parser = argparse.ArgumentParser(description="Download artifact")
    parser.add_argument(
        "--url", required=True, help="Example: https://dev.azure.com/MY_ORGANIZATION"
    )
    parser.add_argument("--access-token", required=True, help="Access token to use.")
    parser.add_argument("--project", required=True, help="Azdo project.")
    parser.add_argument("--build-id", required=True, help="Current build id.")
    parser.add_argument("--artifact-name", required=True, help="Artifact name.")
    parser.add_argument(
        "--output-dir", default=".", type=pathlib.Path, help="Artifact name."
    )
    return parser


def main(argv=None):
    if argv is None:
        argv = sys.argv
    args = parser().parse_args(argv[1:])

    credentials = msrest.authentication.BasicAuthentication("", args.access_token)
    connection = azdo_connection.Connection(base_url=args.url, creds=credentials)
    build_client = connection.clients_v5_1.get_build_client()
    artifact_info = build_client.get_artifact(
        args.project, args.build_id, args.artifact_name
    )
    print(f"Artifact info: {artifact_info}")
    with tempfile.TemporaryFile() as f:
        for i in build_client.get_artifact_content_zip(
            args.project, args.build_id, args.artifact_name
        ):
            f.write(i)
        f.seek(0)
        zf = zipfile.ZipFile(f)
        outdir = args.output_dir
        outdir.mkdir(parents=True, exist_ok=True)
        zf.extractall(path=outdir)


if __name__ == "__main__":
    sys.exit(main())

A workaround I found is to apply this patch:

@@ -40,9 +42,18 @@ def main(argv=None):
     )
     print(f"Artifact info: {artifact_info}")
     with tempfile.TemporaryFile() as f:
-        for i in build_client.get_artifact_content_zip(
-            args.project, args.build_id, args.artifact_name
-        ):
+        try:
+            stream = build_client.get_artifact_content_zip(
+                args.project, args.build_id, args.artifact_name
+            )
+        except AzureDevOpsServiceError as e:
+            if "The user '' is not authorized to access this resource" in e.message:
+                stream = requests.get(
+                    artifact_info.resource.download_url, auth=("", args.access_token)
+                )
+            else:
+                raise
+        for i in stream:
             f.write(i)
         f.seek(0)
         zf = zipfile.ZipFile(f)

Start with the provided Python reproduction and the build_client.get_artifact_content_zip() entry point. Compare its authentication behavior with artifact_info.resource.download_url for artifacts hosted on another domain, using the reported authorization error as the failure signal. Done means artifact ZIP downloads work for both same-host and external download URLs without requiring the caller's workaround.