Adding an optional version env var for the version endpoint to return

Author: alexcottner

src/dockerflow/version.py

@@ -9,15 +9,21 @@
 
 def get_version(root):
     """
-    Load and return the contents of version.json.
+    Load and return the contents of version.json. If a DOCKERFLOW_VERSION
+    env var is set, sets the "version" attribute to the env var value.
 
     :param root: The root path that the ``version.json`` file will be opened
     :type root: str
     :returns: Content of ``version.json`` or None
     :rtype: dict or None
     """
     version_json = os.path.join(root, "version.json")
+    version_env_var = os.getenv("DOCKERFLOW_VERSION")
     if os.path.exists(version_json):
         with open(version_json, "r") as version_json_file:
-            return json.load(version_json_file)
+            version_info = json.load(version_json_file)
+            version_info["version"] = version_env_var or version_info["version"]
+            return version_info
+    if version_env_var != None:
+        return { "version": version_env_var }
     return None

tests/core/test_version.py

@@ -4,6 +4,7 @@
 import json
 
 from dockerflow.version import get_version
+from unittest import mock
 
 
 def test_get_version(tmpdir):
@@ -18,3 +19,22 @@ def test_get_version(tmpdir):
 def test_no_version_json(tmpdir):
     version = get_version(str(tmpdir))
     assert version is None
+
+def test_env_var_override(tmpdir):
+    content = {"spam": "eggs"}
+    mock.patch.dict(os.environ, { "DOCKERFLOW_VERSION": "foo"})
+    version_json = tmpdir.join("version.json")
+    version_json.write(json.dumps(content))
+
+    version = get_version(str(tmpdir))
+    assert version == {
+        "spam": "eggs",
+        "version": "foo"
+    }
+
+def test_env_var_override_with_no_json(tmpdir):
+    mock.patch.dict(os.environ, { "DOCKERFLOW_VERSION": "foo"})
+    version = get_version(str(tmpdir))
+    assert version == {
+        "version": "foo"
+    }