OTLP Exporter

The OpenTelemetry Protocol (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 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 and Collector contributions.

Configuration

The OTLP exporter offers some configuration options. To configure the exporter, create an OtlpGrpcExporterOptions struct (defined in 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), 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 and 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.