Merge pull request #126 from lsst-sqre/tickets/DM-42660

DM-42660: Use Butler repository list from environment var

scripts/start-frontend.sh

@@ -6,7 +6,7 @@ if [ -n "$DATALINKER_TAP_METADATA_URL" ]; then
         exit 1
     fi
     curl -L "$DATALINKER_TAP_METADATA_URL" -o /tmp/datalink-columns.zip
-    unzip /tmp/datalink-columns.zip -d "$DATALINKER_TAP_METADATA_DIR"
+    unzip -o /tmp/datalink-columns.zip -d "$DATALINKER_TAP_METADATA_DIR"
 fi
 
 rm -rf /tmp/secrets

src/datalinker/config.py

@@ -3,11 +3,21 @@
 from __future__ import annotations
 
 import os
-from dataclasses import dataclass
+from dataclasses import dataclass, field
+
+from pydantic import TypeAdapter
 
 __all__ = ["Configuration", "config"]
 
 
+def _get_butler_repositories() -> dict[str, str] | None:
+    json = os.getenv("DAF_BUTLER_REPOSITORIES", None)
+    if json is not None:
+        return TypeAdapter(dict[str, str]).validate_json(json)
+
+    return None
+
+
 @dataclass
 class Configuration:
     """Configuration for datalinker."""
@@ -76,6 +86,18 @@ class Configuration:
     Set with the ``S3_ENDPOINT_URL`` environment variable.
     """
 
+    # TODO DM-42660: butler_repositories can be removed once there is a release
+    # of daf_butler available that handles DAF_BUTLER_REPOSITORIES itself.
+    butler_repositories: dict[str, str] | None = field(
+        default_factory=_get_butler_repositories
+    )
+    """Mapping from label to URI for Butler repositories used by this service.
+
+    Set with the ``DAF_BUTLER_REPOSITORIES`` environment variable.  If not set,
+    Butler will fall back to looking this up from a file whose URI is given in
+    the ``DAF_BUTLER_REPOSITORY_INDEX`` environment variable.
+    """
+
 
 config = Configuration()
 """Configuration for datalinker."""

src/datalinker/handlers/external.py

@@ -31,7 +31,7 @@
 external_router = APIRouter()
 """FastAPI router for all external handlers."""
 
-_BUTLER_FACTORY = LabeledButlerFactory()
+_BUTLER_FACTORY = LabeledButlerFactory(config.butler_repositories)
 """Factory for creating Butlers from a label and Gafaelfawr token."""
 
 _TEMPLATES = Jinja2Templates(