feat: add workers autodicsovery feature (#121)

* add workers autodicsovery feature

* suppress erros while retrieving worker list

* update recipes

* fix tests and update docs

* filter health checks

* ping based workers

recipes/distributed/README.md

@@ -8,4 +8,4 @@
 6. All updates from worker instances are uploaded to the web service.
 7. Repository is available at `http://localhost:8080/repo`.
 
-Note, in this configuration, workers are spawned in replicated mode, thus the backend accesses them in round-robin-like manner.
+In this example, worker list is automatically defined based on the addresses they reported. 

recipes/distributed/compose.yml

@@ -77,6 +77,10 @@ services:
       interval: 10s
       start_period: 30s
 
+    depends_on:
+      backend:
+        condition: service_healthy
+
     command: web
 
 configs:

recipes/distributed/service.ini

@@ -2,7 +2,7 @@
 target = configuration
 
 [build]
-workers = http://worker:8080 http://worker:8080
+triggers = ahriman.core.distributed.WorkerLoaderTrigger ahriman.core.gitremote.RemotePullTrigger ahriman.core.report.ReportTrigger ahriman.core.upload.UploadTrigger ahriman.core.gitremote.RemotePushTrigger
 
 [status]
 username = demo

recipes/distributed/worker.ini

@@ -2,7 +2,7 @@
 target = configuration
 
 [build]
-triggers = ahriman.core.upload.UploadTrigger ahriman.core.report.ReportTrigger
+triggers = ahriman.core.distributed.WorkerTrigger ahriman.core.upload.UploadTrigger ahriman.core.report.ReportTrigger
 
 [status]
 address = http://backend:8080
@@ -20,3 +20,6 @@ wait_timeout = 0
 target = remote-service
 
 [remote-service]
+
+[worker]
+address = http://$HOSTNAME:8080