Add "X-Exodus-Query" header [RHELDST-9321]

Our tests sometimes seem to hit an old version of our lambda, for
unclear reasons. Let's make it possible to query the currently deployed
lambda version so we can at least reliably detect when this happens.

The "X-Exodus-Query" header is primarily used in a request, to provide
the version of exodus-lambda, "X-Exodus-Version" in response.

configuration/exodus-lambda-deploy.yaml

@@ -63,6 +63,7 @@ Resources:
             HeaderBehavior: whitelist
             Headers:
               - Want-Digest
+              - X-Exodus-Query
           QueryStringsConfig:
             QueryStringBehavior: none
 

configuration/lambda_config.template

@@ -18,6 +18,7 @@
   },
   "secret_arn": "$EXODUS_SECRET_ARN",
   "key_id": "$EXODUS_KEY_ID",
+  "lambda_version": "$EXODUS_LAMBDA_VERSION",
   "logging": {
     "version": 1,
     "incremental": "True",

exodus_lambda/functions/base.py

@@ -49,6 +49,10 @@ def logger(self):
     def max_age(self):
         return self.conf["headers"]["max_age"]
 
+    @property
+    def lambda_version(self):
+        return self.conf["lambda_version"]
+
     def set_cache_control(self, uri, response):
         max_age_pattern_whitelist = [
             ".+/PULP_MANIFEST",

exodus_lambda/functions/origin_response.py

@@ -33,6 +33,11 @@ def handler(self, event, context):
                 {"key": "Digest", "value": f"id-sha-256={sum_b64}"}
             ]
 
+        if "headers" in request and "x-exodus-query" in request["headers"]:
+            response["headers"]["x-exodus-version"] = [
+                {"key": "X-Exodus-Version", "value": self.lambda_version}
+            ]
+
         try:
             original_uri = request["headers"]["exodus-original-uri"][0][
                 "value"

scripts/mk-config

@@ -14,4 +14,7 @@ export EXODUS_CONFIG_TABLE=${EXODUS_CONFIG_TABLE:-$PROJECT-config-$ENV_TYPE}
 export EXODUS_SECRET_ARN=${EXODUS_SECRET_ARN}
 export EXODUS_KEY_ID=${EXODUS_KEY_ID}
 
+REVISION="${CODEBUILD_RESOLVED_SOURCE_VERSION:-$(git rev-parse HEAD)}"
+export EXODUS_LAMBDA_VERSION="${EXODUS_LAMBDA_VERSION:-$(date -u --iso=s) ${REVISION}}"
+
 envsubst < ./configuration/lambda_config.template

tests/conftest.py

@@ -63,6 +63,7 @@ def mock_conf_file():
     test_env["EXODUS_KEY_ID"] = "K1MOU91G3N7WPY"
     test_env["ORIGIN_RESPONSE_LOGGER_LEVEL"] = "DEBUG"
     test_env["ORIGIN_REQUEST_LOGGER_LEVEL"] = "DEBUG"
+    test_env["EXODUS_LAMBDA_VERSION"] = "fake version"
 
     cmd = "envsubst < ./configuration/lambda_config.template > {temp_path}"
     cmd = cmd.format(temp_path=temp_file.name)

tests/functions/test_origin_response.py

@@ -11,14 +11,16 @@
 
 
 @pytest.mark.parametrize(
-    "original_uri, want_digest",
+    "original_uri, want_digest, x_exodus_query",
     [
-        ("/some/repo/listing", True),
-        ("/some/repo/repodata/repomd.xml", True),
-        ("/some/repo/ostree/repo/refs/heads/ok/test", False),
+        ("/some/repo/listing", True, False),
+        ("/some/repo/repodata/repomd.xml", True, False),
+        ("/some/repo/ostree/repo/refs/heads/ok/test", False, True),
     ],
 )
-def test_origin_response_valid_headers(original_uri, want_digest):
+def test_origin_response_valid_headers(
+    original_uri, want_digest, x_exodus_query
+):
     event = {
         "Records": [
             {
@@ -59,6 +61,17 @@ def test_origin_response_valid_headers(original_uri, want_digest):
             }
         ]
 
+    if x_exodus_query:
+        event["Records"][0]["cf"]["request"]["headers"]["x-exodus-query"] = [
+            {"key": "X-Exodus-Query", "value": "true"}
+        ]
+        expected_headers["x-exodus-version"] = [
+            {
+                "key": "X-Exodus-Version",
+                "value": "fake version",
+            }
+        ]
+
     response = OriginResponse(conf_file=TEST_CONF).handler(event, context=None)
     assert response["headers"] == expected_headers