feat(opentelemetry): add tracing backend and logging handler

Author: lukaslihotzki-f

.github/workflows/famedly-tests.yml

@@ -359,6 +359,23 @@ jobs:
 
       - run: cargo test
 
+   otlp:
+    if: ${{ !failure() && !cancelled() }}
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Run actions/checkout@v4 for synapse
+        uses: actions/checkout@v4
+        with:
+          path: synapse
+      - run: |
+          set -e
+          DOCKER_BUILDKIT=1 sudo docker build -t famedly/synapse -f docker/Dockerfile .
+          cd otlp-test
+          success() { [ -s out/traces.json ] && [ -s out/logs.json ]; }
+          (until success; do sleep 1; done && sudo docker compose down >/dev/null 2>&1) &
+          sudo timeout 30 docker compose up && success
+
   # a job which marks all the other jobs as complete, thus allowing PRs to be merged.
   tests-done:
     if: ${{ always() }}

docker/conf/homeserver.yaml

@@ -191,3 +191,9 @@ trusted_key_servers:
 
 password_config:
    enabled: true
+
+{% if OTLP_BACKEND %}
+opentracing:
+  enabled: true
+  backend: otlp
+{% endif %}

docker/conf/log.config

@@ -43,6 +43,9 @@ handlers:
     # Messages will not be delayed for longer than this time.
     # Default value: 5 seconds
     period: 5
+{% elif OTLP_BACKEND %}
+  otlp:
+    class: synapse.logging.handlers.OtlpHandler
 {% endif %}
 
   console:
@@ -84,6 +87,8 @@ root:
 
 {% if LOG_FILE_PATH %}
     handlers: [console, buffer]
+{% elif OTLP_BACKEND %}
+    handlers: [console, otlp]
 {% else %}
     handlers: [console]
 {% endif %}

docs/opentracing.md

@@ -6,7 +6,8 @@ OpenTracing is a semi-standard being adopted by a number of distributed
 tracing platforms. It is a common api for facilitating vendor-agnostic
 tracing instrumentation. That is, we can use the OpenTracing api and
 select one of a number of tracer implementations to do the heavy lifting
-in the background. Our current selected implementation is Jaeger.
+in the background. Our current implementations are Jaeger (default) and
+OpenTelemetry.
 
 OpenTracing is a tool which gives an insight into the causal
 relationship of work done in and between servers. The servers each track
@@ -74,6 +75,14 @@ opentracing:
     - "*.myotherhomeservers.com"
 ```
 
+To use OpenTelemetry instead of Jaeger as the `backend`:
+
+```yaml
+opentracing:
+  enabled: true
+  backend: otlp
+```
+
 ## Homeserver whitelisting
 
 The homeserver whitelist is configured using regular expressions. A list

docs/sample_log_config.yaml

@@ -56,6 +56,12 @@ handlers:
         class: logging.StreamHandler
         formatter: precise
 
+    # A commented-out OtlpHandler based on opentelemetry-sdk that reads
+    # its configuration from the common `OTLP_` environment variables:
+    # Requires the extra "opentelemetry-log-handler".
+    #otlp:
+    #    class: synapse.logging.handlers.OtlpHandler
+
 loggers:
     synapse.storage.SQL:
         # beware: increasing this to DEBUG will make synapse log sensitive
@@ -70,6 +76,8 @@ root:
     #
     # Replace "buffer" with "console" to log to stderr instead.
     #
+    # Add or set the handler to "otlp" after enabling it in the "handlers" section.
+    #
     handlers: [buffer]
 
 disable_existing_loggers: false

otlp-test/docker-compose.yaml

@@ -0,0 +1,32 @@
+services:
+
+  init:
+    image: famedly/synapse
+    user: root
+    command: migrate_config
+    volumes:
+      - ./synapse-data:/data
+    environment:
+      - SYNAPSE_SERVER_NAME=example.com
+      - SYNAPSE_REPORT_STATS=no
+      - SYNAPSE_NO_TLS=1
+      - OTLP_BACKEND=1
+
+  synapse:
+    image: famedly/synapse
+    user: root
+    volumes:
+      - ./synapse-data:/data
+    environment:
+       - OTEL_EXPORTER_OTLP_ENDPOINT=http://otel-collector:4318
+    depends_on:
+      - init
+      - otel-collector
+
+  otel-collector:
+    image: otel/opentelemetry-collector:0.86.0
+    user: "0"
+    command: [ "--config=/etc/otel-collector.yaml" ]
+    volumes:
+      - ./otel-collector.yaml:/etc/otel-collector.yaml
+      - ./out:/etc/out

otlp-test/otel-collector.yaml

@@ -0,0 +1,18 @@
+receivers:
+  otlp:
+    protocols:
+      grpc:
+      http:
+exporters:
+  file/traces:
+    path: /etc/out/traces.json
+  file/logs:
+    path: /etc/out/logs.json
+service:
+  pipelines:
+    traces:
+      receivers: [otlp]
+      exporters: [file/traces]
+    logs:
+      receivers: [otlp]
+      exporters: [file/logs]