[collector] - allow for an extras configuration (open-telemetry#246)

* use extras configuration for collector

* add extras collector config

* add extras collector config

CHANGELOG.md

@@ -41,6 +41,8 @@ significant modifications will be credited to OpenTelemetry Authors.
 ([#189](https://github.com/open-telemetry/opentelemetry-demo/pull/189))
 * Simplified repo name and dropped the '-webstore' suffix in every place
 ([#225](https://github.com/open-telemetry/opentelemetry-demo/pull/225))
+* Added ability for repo forks to specify additional collector settings
+([#246](https://github.com/open-telemetry/opentelemetry-demo/pull/246))
 * Add metrics endpoint in adservice to send metrics from java agent
 ([#237](https://github.com/open-telemetry/opentelemetry-demo/pull/237))
 * Support override java agent jar

docker-compose.yml

@@ -28,9 +28,10 @@ services:
   otelcol:
     image: otel/opentelemetry-collector:0.56.0
     container_name: otel-col
-    command: [ "--config=/etc/otelcol-config.yml" ]
+    command: [ "--config=/etc/otelcol-config.yml", "--config=/etc/otelcol-config-extras.yml" ]
     volumes:
       - ./src/otelcollector/otelcol-config.yml:/etc/otelcol-config.yml
+      - ./src/otelcollector/otelcol-config-extras.yml:/etc/otelcol-config-extras.yml
     ports:
       - "4317"
       - "4318"

src/otelcollector/otelcol-config-extras.yml

@@ -0,0 +1,2 @@
+# extra settings to be merged into OpenTelemetry Collector configuration
+# do not delete this file