Add tests, add docu, use subpackage.

README.md

@@ -2,26 +2,66 @@
 
 ## Features
 
- * Buildin appender:
-   * console format
-   * stackdriver format (with support for error reporting)
- * logback filter for log-levels per mdc
+### Preconfigured Appender
 
-## Usage
+Buildin appender:
+ * console format
+ * stackdriver format (with support for error reporting)
 
-MDC example:
+### Set log level based on MDC values
+
+Confguration:
+ * *enabled*: enable MDC filter (`true` is default)
+ * *key*: MDC key, is optional (will use name instead, see example `user` below)
+ * *level*: log level to use (`TRACE` is default)
+ * *loggers*: whitelist of logger names, matches all loggers if empty
+ * *values*: values for matching MDC key, matches all values if empty
+
+Example for setting  different values for different values/logger:
 ```
 logger:
   levels:
     io.kokuwa: INFO
   mdc:
-    gateway:
+    gateway-debug:
+      key: gateway
       level: DEBUG
       loggers:
       - io.kokuwa
       values:
       - 6a1bae7f-eb6c-4c81-af9d-dc15396584e2
       - fb3318f1-2c73-48e9-acd4-a2be3c9f9256
+    gateway-trace:
+      key: gateway
+      level: TRACE
+      loggers:
+      - io.kokuwa
+      - io.micronaut
+      values:
+      - 257802b2-22fe-4dcc-bb99-c1db2a47861f
+```
+
+Example for omiting level and key:
+```
+logger:
+  levels:
+    io.kokuwa: INFO
+  mdc:
+    gateway:
+      loggers:
+      - io.kokuwa
+      values:
+      - 257802b2-22fe-4dcc-bb99-c1db2a47861f
+      - 0a44738b-0c3a-4798-8210-2495485f10b2
+```
+
+Example for minimal configuration:
+```
+logger:
+  levels:
+    io.kokuwa: INFO
+  mdc:
+    user: {}
 ```
 
 ## Build & Release
@@ -47,6 +87,4 @@ mvn release:prepare release:perform release:clean -B
 
 ## Open Topics
 
- * tests
  * configure mdc on refresh event
- * examples and documentation