Allow specifying a single configuration

specification/trace/sdk_exporters/otlp.md

@@ -1,20 +1,54 @@
 # OpenTelemetry Protocol Exporter
 
-This document specifies the configuration options available to the OpenTelemetry Protocol ([OTLP](https://github.com/open-telemetry/oteps/blob/master/text/0035-opentelemetry-protocol.md)) `SpanExporter` and `MetricsExporter` as well as the retry behavior.
+This document specifies the configuration options available to the OpenTelemetry Protocol ([OTLP](https://github.com/open-telemetry/oteps/blob/master/text/0035-opentelemetry-protocol.md)) Exporter as well as the retry behavior.
 
 ## Configuration Options
 
-The configuration options are configurable separately for the `SpanExporter` and the `MetricsExporter`.
+The following configuration options MUST be available to configure the OTLP exporter. Each configuration option MUST be overridable by a signal specific option.
 
 | Configuration Option | Description                                                  | Default           | Env variable                                                 |
 | -------------------- | ------------------------------------------------------------ | ----------------- | ------------------------------------------------------------ |
-| Endpoint             | Target to which the exporter is going to send spans or metrics. This MAY be configured to include a path (e.g. `example.com/v1/traces`). | `localhost:55680` | `OTEL_EXPORTER_OTLP_SPAN_ENDPOINT` `OTEL_EXPORTER_OTLP_METRIC_ENDPOINT` |
-| Protocol             | The protocol used to transmit the data. One of `grpc`,`http/json`,`http/proto`. | `grpc`               | `OTEL_EXPORTER_OTLP_SPAN_PROTOCOL` `OTEL_EXPORTER_OTLP_METRIC_PROTOCOL` |
-| Insecure             | Whether to enable client transport security for the exporter's `grpc` or `http` connection. | `false`           | `OTEL_EXPORTER_OTLP_SPAN_INSECURE` `OTEL_EXPORTER_OTLP_METRIC_INSECURE` |
-| Certificate File     | Certificate file for TLS credentials of gRPC client. Should only be used if `insecure` is set to `false`. | n/a               | `OTEL_EXPORTER_OTLP_SPAN_CERTIFICATE` `OTEL_EXPORTER_OTLP_METRIC_CERTIFICATE` |
-| Headers              | The headers associated with gRPC or HTTP requests.                   | n/a               | `OTEL_EXPORTER_OTLP_SPAN_HEADERS` `OTEL_EXPORTER_OTLP_METRIC_HEADERS` |
-| Compression          | Compression key for supported compression types. Supported compression: `gzip`| no compression              | `OTEL_EXPORTER_OTLP_SPAN_COMPRESSION` `OTEL_EXPORTER_OTLP_METRIC_COMPRESSION` |
-| Timeout              | Max waiting time for the backend to process each spans or metrics batch. | 60s               | `OTEL_EXPORTER_OTLP_SPAN_TIMEOUT` `OTEL_EXPORTER_OTLP_METRIC_TIMEOUT` |
+| Endpoint             | Target to which the exporter is going to send spans or metrics. This MAY be configured to include a path (e.g. `example.com/v1/traces`). | `localhost:55680` | `OTEL_EXPORTER_OTLP_ENDPOINT` `OTEL_EXPORTER_OTLP_SPAN_ENDPOINT` `OTEL_EXPORTER_OTLP_METRIC_ENDPOINT` |
+| Protocol             | The protocol used to transmit the data. One of `grpc`,`http/json`,`http/proto`. | `grpc`               | `OTEL_EXPORTER_OTLP_PROTOCOL` `OTEL_EXPORTER_OTLP_SPAN_PROTOCOL` `OTEL_EXPORTER_OTLP_METRIC_PROTOCOL` |
+| Insecure             | Whether to enable client transport security for the exporter's `grpc` or `http` connection. | `false`           | `OTEL_EXPORTER_OTLP_INSECURE` `OTEL_EXPORTER_OTLP_SPAN_INSECURE` `OTEL_EXPORTER_OTLP_METRIC_INSECURE` |
+| Certificate File     | Certificate file for TLS credentials of gRPC client. Should only be used if `insecure` is set to `false`. | n/a               | `OTEL_EXPORTER_OTLP_CERTIFICATE` `OTEL_EXPORTER_OTLP_SPAN_CERTIFICATE` `OTEL_EXPORTER_OTLP_METRIC_CERTIFICATE` |
+| Headers              | The headers associated with gRPC or HTTP requests.                   | n/a               | `OTEL_EXPORTER_OTLP_HEADERS` `OTEL_EXPORTER_OTLP_SPAN_HEADERS` `OTEL_EXPORTER_OTLP_METRIC_HEADERS` |
+| Compression          | Compression key for supported compression types. Supported compression: `gzip`| no compression              | `OTEL_EXPORTER_OTLP_COMPRESSION` `OTEL_EXPORTER_OTLP_SPAN_COMPRESSION` `OTEL_EXPORTER_OTLP_METRIC_COMPRESSION` |
+| Timeout              | Max waiting time for the backend to process each spans or metrics batch. | 60s               | `OTEL_EXPORTER_OTLP_TIMEOUT` `OTEL_EXPORTER_OTLP_SPAN_TIMEOUT` `OTEL_EXPORTER_OTLP_METRIC_TIMEOUT` |
+
+Example 1
+
+The following configuration sends all signals to the same collector:
+
+```bash
+export OTEL_EXPORTER_OTLP_ENDPOINT=collector:55680
+export OTEL_EXPORTER_OTLP_PROTOCOL=grpc
+```
+
+Example 2
+
+Traces and metrics are sent to different collectors using different protocols:
+
+```bash
+export OTEL_EXPORTER_OTLP_SPAN_ENDPOINT=collector:55680
+export OTEL_EXPORTER_OTLP_SPAN_PROTOCOL=grpc
+export OTEL_EXPORTER_OTLP_SPAN_INSECURE=true
+
+export OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=collector.example.com/v1/metrics
+export OTEL_EXPORTER_OTLP_METRICS_PROTOCOL=http
+```
+
+Example 3
+
+Traces are configured using the generic configuration, metrics are configured using specific configuration:
+
+```bash
+export OTEL_EXPORTER_OTLP_ENDPOINT=collector:55680
+export OTEL_EXPORTER_OTLP_PROTOCOL=grpc
+
+export OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=collector.example.com/v1/metrics
+export OTEL_EXPORTER_OTLP_METRICS_PROTOCOL=http
+```
 
 ## Retry