Added basic docs for sapm receiver and exporter components (#110)

exporter/sapmexporter/README.md

@@ -0,0 +1,40 @@
+# SAPM Exporter
+
+SAPM exports builds on the Jaeger proto and adds additional batching on top. This allows
+the collector to export traces from multiples nodes/services in a single batch. SAPM proto
+and some useful related utilities can be found [here](https://github.com/signalfx/sapm-proto/).
+
+## Configuration
+
+Example:
+
+```yaml
+exporters:
+  sapm:
+    endpoint: https://ingest.YOUR_SIGNALFX_REALM.signalfx.com
+    access_token: abcd1234
+    num_workers: 8
+    max_connections: 100
+```
+
+* `endpoint`: This is the destination to where traces will be sent to in SAPM format. It must be a full URL and include the scheme, port and path e.g, https://ingest.us0.signalfx.com/v2/trace. This can be pointed to the SignalFx backend or to another Otel collector that has the SAPM receiver enabled. Has no default value.
+
+* `access_token`: AccessToken is the authentication token provided by SignalFx or another backend that supports the SAPM proto. Has no default value.
+
+* `num_workers`: NumWorkers is the number of workers that should be used to export traces. Exporter can make as many requests in parallel as the number of workers. Note that this will likely be removed in future in favour of processors handling parallel exporting. Defaults to `8`.
+
+* `max_connections`: MaxConnections is used to set a limit to the maximum idle HTTP connection the exporter can keep open. Defaults to `100`.
+
+
+## Proxy Support
+
+Beyond standard YAML configuration as outlined in the sections that follow,
+exporters that leverage the net/http package (all do today) also respect the
+following proxy environment variables:
+
+* HTTP_PROXY
+* HTTPS_PROXY
+* NO_PROXY
+
+If set at Collector start time then exporters, regardless of protocol,
+will or will not proxy traffic as defined by these environment variables.

exporter/sapmexporter/testdata/config.yaml

@@ -18,9 +18,8 @@ exporters:
     # NumWorkers is the number of workers that should be used to export traces.
     # Exporter can make as many requests in parallel as the number of workers.
     num_workers: 3
-
-    # MaxRetries is maximum number of retry attempts the exporter should make before dropping a span batch.
-    # Note that right now this is only used when the server responds with HTTP 429 (tries to rate limit the client)
+
+    # MaxConnections is used to set a limit to the maximum idle HTTP connection the exporter can keep open.
     max_connections: 45
   sapm/disabled: # will be ignored
     disabled: true

receiver/sapmreceiver/README.md

@@ -0,0 +1,17 @@
+# SAPM Receiver 
+
+SAPM exports builds on the Jaeger proto and adds additional batching on top. This allows
+the collector to export traces from multiples nodes/services in a single batch. SAPM proto
+and some useful related utilities can be found [here](https://github.com/signalfx/sapm-proto/).
+
+## Configuration
+
+Example:
+
+```yaml
+exporters:
+  sapm:
+    endpoint: localhost:7276
+```
+
+* `endpoint`: Address and port that the SAPM receiver should bind to. Note that this must be 0.0.0.0:<port> instead of localhost if you want to receive spans from sources exporting to IPs other than localhost on the same host. For example, when the collector is deployed as a k8s deployment and exposed using a service.