Exporters
In order to visualize and analyze your telemetry, you will need to export your data to an OpenTelemetry Collector or a backend such as Jaeger, Zipkin, Prometheus or a vendor-specific one.
As part of OpenTelemetry Erlang/Elixir you will find many exporters being available. Among them, the OpenTelemetry Protocol (OTLP) exporters provide the best experience for you as an end-user, since it is a general-purpose telemetry data delivery protocol designed in the scope of the OpenTelemetry project.
To learn more about the OTLP protocol, you can read the OTLP Specification.
Below you will find some introductions on how to set up exporters for OTLP and other common protocols in your code.
Exporting to the OpenTelemetry Collector
The Collector provides a vendor agnostic way to receive, process and export telemetry data. The package opentelemetry_exporter provides support for both exporting over both HTTP (the default) and gRPC to the collector, which can then export Spans to a self-hosted service like Zipkin or Jaeger, as well as commercial services. For a full list of available exporters, see the registry.
For testing purposes the opentelemetry-erlang repository has a Collector
configuration,
config/otel-collector-config.yaml
that can be used as a starting point. This configuration is used in
docker-compose.yml
to start the Collector with receivers for both HTTP and gRPC that then export to
Zipkin also run by docker-compose.
To export to the running Collector the opentelemetry_exporter package must be
added to the project’s dependencies:
{deps, [{opentelemetry_api, "~> 1.2"},
{opentelemetry, "~> 1.3"},
{opentelemetry_exporter, "~> 1.6"}]}.
def deps do
[
{:opentelemetry_api, "~> 1.2"},
{:opentelemetry, "~> 1.3"},
{:opentelemetry_exporter, "~> 1.6"}
]
end
It should then be added to the configuration of the Release before the SDK Application to ensure the exporter’s dependencies are started before the SDK attempts to initialize and use the exporter.
Example of Release configuration in rebar.config and for
mix’s Release task:
%% rebar.config
{relx, [{release, {my_instrumented_release, "0.1.0"},
[opentelemetry_exporter,
{opentelemetry, temporary},
my_instrumented_app]},
...]}.
# mix.exs
def project do
[
releases: [
my_instrumented_release: [
applications: [opentelemetry_exporter: :permanent, opentelemetry: :temporary]
],
...
]
]
end
Finally, the runtime configuration of the opentelemetry and
opentelemetry_exporter Applications are set to export to the Collector. The
configurations below show the defaults that are used if none are set, which are
the HTTP protocol with endpoint of localhost on port 4318. If using grpc
for the otlp_protocol the endpoint should be changed to
http://localhost:4317.
%% config/sys.config.src
[
{opentelemetry,
[{span_processor, batch},
{traces_exporter, otlp}]},
{opentelemetry_exporter,
[{otlp_protocol, http_protobuf},
{otlp_endpoint, "http://localhost:4318"}]}]}
].
# config/runtime.exs
config :opentelemetry,
span_processor: :batch,
traces_exporter: :otlp
config :opentelemetry_exporter,
otlp_protocol: :http_protobuf,
otlp_endpoint: "http://localhost:4318"