Support reporting expected models (#911)

gordo/server/server.py

@@ -14,7 +14,7 @@
 import subprocess
 from functools import wraps
 
-
+import yaml
 from flask import Flask, g, request, current_app, make_response, jsonify
 from gordo.server import views
 from gordo import __version__
@@ -25,7 +25,9 @@
 class Config:
     """Server config"""
 
-    MODEL_COLLECTION_DIR_ENV_VAR = "MODEL_COLLECTION_DIR"
+    def __init__(self):
+        self.MODEL_COLLECTION_DIR_ENV_VAR = "MODEL_COLLECTION_DIR"
+        self.EXPECTED_MODELS = yaml.safe_load(os.getenv("EXPECTED_MODELS", "[]"))
 
 
 def adapt_proxy_deployment(wsgi_app: typing.Callable) -> typing.Callable:

gordo/server/views/base.py

@@ -268,7 +268,14 @@ def get(self, gordo_project: str):
         )
 
 
+class ExpectedModels(Resource):
+    @api.doc(description="Models that the server expects to be able to serve.")
+    def get(self, gordo_project: str):
+        return jsonify({"expected-models": current_app.config["EXPECTED_MODELS"]})
+
+
 api.add_resource(ModelListView, "/gordo/v0/<gordo_project>/models")
+api.add_resource(ExpectedModels, "/gordo/v0/<gordo_project>/expected-models")
 api.add_resource(BaseModelView, "/gordo/v0/<gordo_project>/<gordo_name>/prediction")
 api.add_resource(
     MetaDataView,

gordo/workflow/workflow_generator/resources/argo-workflow.yml.template

@@ -876,6 +876,8 @@ spec:
                                  value: /gordo/models/{{project_name}}/{{project_revision}}
                                - name: GORDO_LOG_LEVEL
                                  value: "{{log_level}}"
+                               - name: EXPECTED_MODELS
+                                 value: [{% for machine in machines %}"{{ machine.name }}",{% endfor %}]
 
                              resources:
                                requests:

tests/gordo/server/test_gordo_server.py

@@ -295,3 +295,20 @@ def test_non_existant_model_metadata(tmpdir, gordo_project, api_version):
             f"/gordo/{api_version}/{gordo_project}/model-does-not-exist/metadata"
         )
         assert resp.status_code == 404
+
+
+def test_expected_models_route(tmpdir):
+    """
+    Route that gives back the expected models names, which are just read from
+    the 'EXPECTED_MODELS' env var.
+    """
+    with tu.temp_env_vars(
+        MODEL_COLLECTION_DIR=str(tmpdir),
+        EXPECTED_MODELS=json.dumps(["model-a", "model-b"]),
+    ):
+        app = server.build_app()
+        app.testing = True
+        client = app.test_client()
+
+        resp = client.get("/gordo/v0/test-project/expected-models")
+        assert resp.json["expected-models"] == ["model-a", "model-b"]

tests/gordo/workflow/test_workflow_generator/test_workflow_generator.py

@@ -480,3 +480,23 @@ def test_log_level_key(test_file: str, log_level: str, path_to_config_files: str
 
     # Assert all the values to the GORDO_LOG_LEVEL key contains the correct log-level
     assert all([log_level in value for value in gordo_log_levels])
+
+
+def test_expected_models_in_workflow(repo_dir):
+    """
+    Server deployment depends on EXPECTED_MODELS env var being set,
+    which is a list of strings, indicating the expected model names to be served.
+    """
+    workflow_str = _generate_test_workflow_str(
+        path_to_config_files=os.path.join(repo_dir, "examples"),
+        config_filename="config.yaml",
+    )
+    assert "name: EXPECTED_MODELS" in workflow_str
+
+    # Not the prettiest, but a whole lot prettier than digging down into the workflow yaml
+    # basically want to get to 'gordo-server-deployment' and ensure the EXPECTED_MODELS env var
+    # is set with a list (in string form) of model names which can be loaded.
+    expected_models_str = (
+        workflow_str.split("EXPECTED_MODELS")[1].split("value:")[1].split("\n")[0]
+    )
+    assert isinstance(yaml.safe_load(expected_models_str), list)