PR 110 redux

cats/configure.py

@@ -12,6 +12,7 @@
 
 import logging
 import sys
+import os
 from collections.abc import Mapping
 from typing import Any, Optional
 
@@ -76,7 +77,16 @@
             return yaml.safe_load(f)
         logging.info(f"Using provided config file: {configpath}\n")
     else:
-        # if no path provided, look for `config.yml` in current directory
+        # if no path provided, try to use config environment variable
+        cfile = os.getenv("CATS_CONFIG_FILE")
+        if cfile is not None:
+            try:
+                with open(cfile, "r") as f:
+                    return yaml.safe_load(f)
+                logging.info("Using config.yml found in CATS_CONFIG_FILE\n")
+            except FileNotFoundError:
+                logging.warning("CATS_CONFIG_FILE config file not found")
+        # if no path provided and no env variable, look for `config.yml` in current directory
         try:
             with open("config.yml", "r") as f:
                 return yaml.safe_load(f)

docs/source/quickstart.rst

@@ -45,7 +45,9 @@ Use the ``--config`` option to specify a path to the configuration
 file, relative to the current directory.
 
 In case of a missing location command line argument, ``cats`` looks
-for a file named ``config.yaml`` or ``config.yml`` in the current directory.
+first in the ``CATS_CONFIG_FILE`` environment variable and if that
+is not set it looks for a file named ``config.yaml`` or ``config.yml``
+in the current directory.
 
 .. code-block:: shell
 
@@ -67,7 +69,16 @@ machine IP address:
    Carbon intensity if job started now       = 117.95 gCO2eq/kWh
    Carbon intensity at optimal time          = 60.93 gCO2eq/kWh
 
-   Use --format=json to get this in machine readable format
+Use --format=json to get this in machine readable format
+
+.. code-block::console
+
+   # location information is provided by the file
+   # specified in $CATS_CONFIG_FILE
+   # If not, it looks for ./config.yaml
+   # otherwise 'cats' errors out.
+   export CATS_CONFIG_FILE=/path/to/config.yaml
+   cats --duration 480
 
 
 Displaying carbon footprint estimates

tests/test_configure.py

@@ -50,6 +50,12 @@ def test_config_from_file_default(local_config_file):
     assert configmapping == CATS_CONFIG
 
 
+def test_config_from_env(local_config_file):
+    os.environ["CATS_CONFIG_FILE"] = str(local_config_file / "config.yml")
+    configmapping = config_from_file()
+    assert configmapping == CATS_CONFIG
+
+
 @patch("cats.configure.requests")
 def test_get_location_from_config_or_args(mock_requests):
     expected_location = "SW7"