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# OTLP Exporter
The [OpenTelemetry
Protocol](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/README.md)
(OTLP) is a vendor-agnostic protocol designed as part of the OpenTelemetry
project. The OTLP exporter can be used to export to any backend that supports
OTLP.
The [OpenTelemetry
Collector](https://github.com/open-telemetry/opentelemetry-collector) is a
reference implementation of an OTLP backend. The Collector can be configured to
export to many other backends, such as Zipkin and Jaegar.
For a full list of backends supported by the Collector, see the [main Collector
repo](https://github.com/open-telemetry/opentelemetry-collector/tree/main/exporter)
and [Collector
contributions](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/exporter).
## Configuration
The OTLP exporter offers some configuration options. To configure the exporter,
create an `OtlpGrpcExporterOptions` struct (defined in
[otlp_grpc_exporter.h](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_grpc_exporter.h)),
set the options inside, and pass the struct to the `OtlpGrpcExporter` constructor,
like so:
```cpp
OtlpGrpcExporterOptions options;
options.endpoint = "localhost:12345";
auto exporter = std::unique_ptr<sdktrace::SpanExporter>(new otlp::OtlpGrpcExporter(options));
```
The OTLP HTTP exporter offers some configuration options. To configure the exporter,
create an `OtlpHttpExporterOptions` struct (defined in
[otlp_http_exporter.h](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_http_exporter.h)),
set the options inside, and pass the struct to the `OtlpHttpExporter` constructor,
like so:
```cpp
OtlpHttpExporterOptions options;
options.url = "localhost:12345";
auto exporter = std::unique_ptr<sdktrace::SpanExporter>(new otlp::OtlpHttpExporter(options));
```
The OTLP File exporter offers some configuration options. To configure the exporter,
create an `OtlpFileExporterOptions` struct (defined in
[otlp_file_exporter_options.h](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_file_exporter_options.h)
and
[otlp_file_client_options.h](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/exporters/otlp/include/opentelemetry/exporters/otlp/otlp_file_client_options.h)),
set the options inside, and pass the struct to the `OtlpFileExporter` constructor,
like so:
```cpp
OtlpFileExporterOptions options;
OtlpFileClientFileSystemOptions fs_backend;
fs_backend.file_pattern = "trace.%N.log";
options.backend_options = fs_backend;
auto exporter = std::unique_ptr<sdktrace::SpanExporter>(new otlp::OtlpFileExporter(options));
```
### Configuration options ( OTLP GRPC Exporter )
| Option | Env Variable | Default | Description |
|----------------------------------|----------------------------------------------|-----------------------|--------------------------------------|
|`endpoint` |`OTEL_EXPORTER_OTLP_ENDPOINT` |`http://localhost:4317`| The OTLP GRPC endpoint to connect to |
| |`OTEL_EXPORTER_OTLP_TRACES_ENDPOINT` | | |
|`use_ssl_credentials` |`OTEL_EXPORTER_OTLP_SSL_ENABLE` | `false` | Whether the endpoint is SSL enabled |
| |`OTEL_EXPORTER_OTLP_TRACES_SSL_ENABLE` | | |
|`ssl_credentials_cacert_path` |`OTEL_EXPORTER_OTLP_CERTIFICATE` | `""` | SSL Certificate file path |
| |`OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE` | | |
|`ssl_credentials_cacert_as_string`|`OTEL_EXPORTER_OTLP_CERTIFICATE_STRING` | `""` | SSL Certifcate as in-memory string |
| |`OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE_STRING`| | |
|`timeout` |`OTEL_EXPORTER_OTLP_TIMEOUT` | `10s` | GRPC deadline |
| |`OTEL_EXPORTER_OTLP_TRACES_TIMEOUT` | | |
|`metadata` |`OTEL_EXPORTER_OTLP_HEADERS` | | Custom metadata for GRPC |
| |`OTEL_EXPORTER_OTLP_TRACES_HEADERS` | | |
### Configuration options ( OTLP HTTP Exporter )
| Option | Env Variable | Default | Description |
|--------------------|------------------------------------|---------------------------------|-------------------------------------------------------------------|
|`url` |`OTEL_EXPORTER_OTLP_ENDPOINT` |`http://localhost:4318` | The OTLP HTTP endpoint to connect to |
| |`OTEL_EXPORTER_OTLP_TRACES_ENDPOINT`| | |
|`content_type` | n/a | `application/json` | Data format used - JSON or Binary |
|`json_bytes_mapping`| n/a | `JsonBytesMappingKind::kHexId` | Encoding used for trace_id and span_id |
|`use_json_name` | n/a | `false` | Whether to use json name of protobuf field to set the key of json |
|`timeout` |`OTEL_EXPORTER_OTLP_TIMEOUT` | `10s` | http timeout |
| |`OTEL_EXPORTER_OTLP_TRACES_TIMEOUT` | | |
|`http_headers` |`OTEL_EXPORTER_OTLP_HEADERS` | | http headers |
| |`OTEL_EXPORTER_OTLP_TRACES_HEADERS` | | |
### Configuration options ( OTLP File Exporter )
| Option | Env Variable | Default | Description |
|--------------------|------------------------------------|---------------------------------|-------------------------------------------------------------------|
|`backend_options` | n/a |`OtlpFileClientFileSystemOptions`| The OTLP FILE backend |
The backend for OTLP File Exporter can be `OtlpFileClientFileSystemOptions` (which
support basic log rotate and alias), and reference to `std::ostream` or custom `OtlpFileAppender`.
#### Configuration options ( File System Backend for OTLP File Exporter )
| Option | Env Variable | Default | Description |
|--------------------|------------------------------------|---------------------------------|-------------------------------------------------------------------|
|`file_pattern` | n/a |`trace-%N.jsonl` | The file pattern to use |
| | |`metrics-%N.jsonl` | |
| | |`logs-%N.jsonl` | |
|`alias_pattern` | n/a | `trace-latest.jsonl` | The file which always point to the latest file |
| | | `metrics-latest.jsonl` | |
| | | `logs-latest.jsonl` | |
|`flush_interval` | n/a | `30s` | Interval to force flush ostream |
|`flush_count` | n/a | `256` | Force flush ostream every `flush_count` records |
|`file_size` | n/a | `20MB` | File size to rotate log files |
|`rotate_size` | n/a | | Rotate count |
Some special placeholders are available for `file_pattern` and `alias_pattern`:
+ `%Y`: Writes year as a 4 digit decimal number
+ `%y`: Writes last 2 digits of year as a decimal number (range [00,99])
+ `%m`: Writes month as a decimal number (range [01,12])
+ `%j`: Writes day of the year as a decimal number (range [001,366])
+ `%d`: Writes day of the month as a decimal number (range [01,31])
+ `%w`: Writes weekday as a decimal number, where Sunday is 0 (range [0-6])
+ `%H`: Writes hour as a decimal number, 24 hour clock (range [00-23])
+ `%I`: Writes hour as a decimal number, 12 hour clock (range [01,12])
+ `%M`: Writes minute as a decimal number (range [00,59])
+ `%S`: Writes second as a decimal number (range [00,60])
+ `%F`: Equivalent to "%Y-%m-%d" (the ISO 8601 date format)
+ `%T`: Equivalent to "%H:%M:%S" (the ISO 8601 time format)
+ `%R`: Equivalent to "%H:%M"
+ `%N`: Rotate index, start from 0
+ `%n`: Rotate index, start from 1
## Example
For a complete example demonstrating how to use the OTLP exporter, see
[examples/otlp](https://github.com/open-telemetry/opentelemetry-cpp/blob/main/examples/otlp/).
|
