Move logging configuration to config file

Author: gjbex

source-code/hydra/README.md

@@ -51,6 +51,14 @@ or
 $ ./gen_rand.py  --config-name=file_config.yaml
 ```
 
+Application logging is configured through Hydra in
+`conf/hydra/job_logging/custom.yaml`.  The script still uses Python's
+`logging.getLogger(__name__)`, but formatting and log level are controlled
+from configuration.  For example, to change the root log level:
+```bash
+$ ./gen_rand.py  hydra.job_logging.root.level=DEBUG
+```
+
 To perform multiple runs with different parameter values:
 ```bash
 $ ./gen_rand.py -m distr=uniform,gauss

source-code/hydra/conf/config.yaml

@@ -2,4 +2,5 @@ n: 1
 file: false
 defaults:
   - distr: gauss
+  - override hydra/job_logging: custom
   - _self_

source-code/hydra/conf/hydra/job_logging/custom.yaml

@@ -0,0 +1,14 @@
+version: 1
+formatters:
+  simple:
+    format: '[%(asctime)s][%(name)s][%(levelname)s] %(message)s'
+handlers:
+  console:
+    class: logging.StreamHandler
+    formatter: simple
+    stream: ext://sys.stdout
+root:
+  level: INFO
+  handlers:
+    - console
+disable_existing_loggers: false