otlp

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:

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:

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:

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.