Add default extensions

docs/README.md

@@ -14,21 +14,22 @@ Then create a `services.json` file for your config, like this:
 
 ```json
 {
+    "global-args": {
+        "default-checker": "CheckerTemplate",
+        "default-alerts": "AlertsTemplate",
+        "default-logging": "LoggingTemplate"
+    },
     "site": {
         "name": "A Website",
-        "checker": "CheckerTemplate",
+        "checker": "HttpChecker",
         "checker-args": {
-            "url": "https://example.net",
-            "port": 443,
-            "lol": "CheckerTemplate ignores these options lol"
+            "url": "https://example.com"
         },
         "rate": 1,
-        "alerts": "AlertsTemplate",
         "alerts-args": {
             "url": "https://example.com/webhook-url-or-whatever-goes-here",
             "lol": "irrelevant, AlertsTemplate ignores these options lol"
         },
-        "logging": "LoggingTemplate",
         "logging-args": {
             "file": "/home/askiiart/Documents/updog/logs/site-log"
         }
@@ -36,15 +37,25 @@ Then create a `services.json` file for your config, like this:
 }
 ```
 
+#### Global config
+
+Optional arguments:
+
+- `default-checker`: The default checker for all services, can be overriden per-service using `checker`
+- `default-alerts`: The default alerter extension for all services, can be overriden per-service using `alerts`
+- `default-logging`: The default logging extension for all services, can be overriden per-service using `logging`
+
+#### Service config
+
 Required arguments:
 
 - The key (in this case `site`): A unique string to identify the service in logs, also used internally.
-- `checker`: The name of the checker extension's *class*.
+- `checker`: The name of the checker extension's *class* - optional if `default-checker` is specified in the global arguments.
 - `checker-args`: Arguments for the checker. Check the checker's docs for what to put here.
 - `rate`: How often to check if the service is up (every *x* seconds)
-- `alerts`: The name of the alerting extension's *class*.
+- `alerts`: The name of the alerting extension's *class* - optional if `default-alerts` is specified in the global arguments.
 - `alerts-args`: Arguments for the alerting extension. Check the alerter's docs for what to put here.
-- `logging`: The name of the logging extension's *class*.
+- `logging`: The name of the logging extension's *class* - optional if `default-logging` is specified in the global arguments.
 - `logging-args`: Arguments for the logging extension. Check the logger's docs for what to put here.
 
 Optional arguments: