Send Erlang and Elixir logs and traces to Bronto

This page covers instrumenting an Erlang or Elixir application with the OpenTelemetry SDK to send logs and traces to Bronto over OTLP/HTTP via a local OTel Collector. Both signals are co-equal: logs are captured via the kernel logger handler automatically, and traces are created using the OTel API macros and functions.

If you don’t have a Collector and want to export directly from your application to Bronto, see Direct export to Bronto at the bottom of this page.

Prerequisites

Erlang/OTP 24 or later, or Elixir 1.13 or later
Rebar3 (Erlang) or Mix (Elixir)
A running OTel Collector configured to forward logs and traces to Bronto — see Connect Open Telemetry to Bronto
OpenTelemetry Erlang/Elixir SDK documentation

Install dependencies

def deps do
  [
    {:opentelemetry_api, "~> 1.4"},
    {:opentelemetry, "~> 1.4"},
    {:opentelemetry_exporter, "~> 1.7"}
  ]
end

{deps, [
  {opentelemetry_api, "~> 1.4"},
  {opentelemetry, "~> 1.4"},
  {opentelemetry_exporter, "~> 1.7"}
]}.

Package	Purpose
`opentelemetry_api`	Core OTel API
`opentelemetry`	SDK — `LoggerProvider`, processors, kernel log handler
`opentelemetry_exporter`	OTLP/HTTP exporter

Configure the log bridge

The OTel SDK ships an Erlang kernel logger handler (otel_log_handler) that captures all log events emitted via :logger (Erlang) or Logger (Elixir). Configure it in your application config.

import Config

config :opentelemetry,
  resource: [
    service: [
      name: "my-service",
      namespace: "my-team"
    ],
    "deployment.environment": "production"
  ],
  logs_exporter: :otlp

config :opentelemetry_exporter,
  otlp_protocol: :http_protobuf,
  otlp_logs_endpoint: "http://localhost:4318/v1/logs"

[
  {opentelemetry, [
    {resource, #{
      <<"service.name">>      => <<"my-service">>,
      <<"service.namespace">> => <<"my-team">>,
      <<"deployment.environment">> => <<"production">>
    }},
    {logs_exporter, otlp}
  ]},
  {opentelemetry_exporter, [
    {otlp_protocol, http_protobuf},
    {otlp_logs_endpoint, "http://localhost:4318/v1/logs"}
  ]}
].

No code changes are required — the kernel logger handler is installed automatically when the opentelemetry application starts.

Set resource attributes

Resource attributes are attached to every log record exported from this process. Two attributes drive how Bronto organises incoming logs:

OTel attribute	Bronto concept	Description
`service.name`	Dataset	Groups logs from one service
`service.namespace`	Collection	Groups related services or a team’s services

These are set via the resource config key in the setup above.

Complete example

# Existing Logger calls work unchanged
require Logger

Logger.info("Application started")
Logger.warning("Low disk space", disk_free_gb: 2.1)
Logger.error("Database connection failed", reason: :timeout)

%% Existing logger calls work unchanged
?LOG_INFO("Application started"),
?LOG_WARNING("Low disk space ~p GB free", [2.1]),
?LOG_ERROR("Database connection failed: ~p", [timeout]).

Existing Logger / :logger calls require no changes. The OTel handler runs alongside any existing handlers (console, file) configured in your kernel logger setup.

Verify delivery

After running your application, check both signals in Bronto:

Logs: open the Search page and filter by the dataset name you set in service.name — your log records should appear within a few seconds.
Traces: open the Explore Traces page and filter by the same service.name — your spans should appear within a few seconds.

If no logs appear, check:

The OTel Collector is running and reachable at the configured endpoint.
The Collector’s pipeline includes a logs pipeline with an otlp receiver and the Bronto exporter — see Connect Open Telemetry to Bronto.
The opentelemetry application is started before your application (listed in extra_applications or applications in your .app.src/mix.exs).

Traces

Framework-specific instrumentation libraries are available for Phoenix, Ecto, LiveView, Absinthe, and more — add opentelemetry_phoenix, opentelemetry_ecto, etc. to your deps and they instrument those frameworks automatically. See Erlang/Elixir instrumentation libraries for the full list.

Configure tracing

Tracing is included in the same opentelemetry and opentelemetry_exporter packages — no additional dependencies are needed. Add the traces endpoint to your config:

config :opentelemetry,
  resource: [
    service: [name: "my-service", namespace: "my-team"],
    "deployment.environment": "production"
  ],
  traces_exporter: :otlp,
  logs_exporter: :otlp

config :opentelemetry_exporter,
  otlp_protocol: :http_protobuf,
  otlp_traces_endpoint: "http://localhost:4318/v1/traces",
  otlp_logs_endpoint: "http://localhost:4318/v1/logs"

{opentelemetry, [
  {resource, #{
    <<"service.name">>      => <<"my-service">>,
    <<"service.namespace">> => <<"my-team">>,
    <<"deployment.environment">> => <<"production">>
  }},
  {traces_exporter, otlp},
  {logs_exporter, otlp}
]},
{opentelemetry_exporter, [
  {otlp_protocol, http_protobuf},
  {otlp_traces_endpoint, "http://localhost:4318/v1/traces"},
  {otlp_logs_endpoint, "http://localhost:4318/v1/logs"}
]}

Creating spans

require OpenTelemetry.Tracer, as: Tracer

Tracer.with_span "process-payment" do
  Tracer.set_attributes([{"payment.amount", 99.99}, {"payment.currency", "USD"}])
  Logger.info("Processing payment")  # trace_id and span_id injected automatically
end

?with_span(<<"process-payment">>, #{}, fun(_SpanCtx) ->
  ?set_attributes([{<<"payment.amount">>, 99.99}]),
  ?LOG_INFO("Processing payment")
end)

Any log emitted inside a span will automatically have trace_id and span_id attached.

GenAI semantic conventions

If your application calls an LLM, OpenTelemetry defines GenAI semantic conventions. There is no first-party GenAI auto-instrumentation package for Erlang/Elixir yet — set the attributes yourself around each LLM call:

This page was verified on July 17, 2026. GenAI libraries and semantic conventions are evolving rapidly, so package configuration and emitted attributes can change between releases. Keep your instrumentation current and verify the fields emitted by the version you deploy.

require OpenTelemetry.Tracer, as: Tracer

Tracer.with_span "chat gpt-4o-mini" do
  Tracer.set_attributes([
    {"gen_ai.provider.name", "openai"},
    {"gen_ai.request.model", "gpt-4o-mini"},
    {"gen_ai.usage.input_tokens", 33},
    {"gen_ai.usage.output_tokens", 74},
    {"gen_ai.response.finish_reasons", ["stop"]}
  ])
end

?with_span(<<"chat gpt-4o-mini">>, #{}, fun(_SpanCtx) ->
  ?set_attributes([
    {<<"gen_ai.provider.name">>, <<"openai">>},
    {<<"gen_ai.request.model">>, <<"gpt-4o-mini">>},
    {<<"gen_ai.usage.input_tokens">>, 33},
    {<<"gen_ai.usage.output_tokens">>, 74},
    {<<"gen_ai.response.finish_reasons">>, [<<"stop">>]}
  ])
end)

Message content (gen_ai.input.messages / gen_ai.output.messages) is opt-in by convention in languages with auto-instrumentation, off by default. Since you’re setting attributes by hand here, apply the same discipline — gate prompt/response content behind your own config flag rather than always sending it.

See LLM Observability for the full recommended attribute set and how to search and aggregate GenAI fields in Bronto.

Direct export to Bronto

If you are not using an OTel Collector, export directly to Bronto by replacing the exporter endpoints and adding your API key:

config :opentelemetry_exporter,
  otlp_protocol: :http_protobuf,
  otlp_logs_endpoint: "https://ingestion.eu.bronto.io/v1/logs",
  otlp_traces_endpoint: "https://ingestion.eu.bronto.io/v1/traces",
  otlp_headers: [{"x-bronto-api-key", "<YOUR_API_KEY>"}]

{opentelemetry_exporter, [
  {otlp_protocol, http_protobuf},
  {otlp_logs_endpoint, "https://ingestion.eu.bronto.io/v1/logs"},
  {otlp_traces_endpoint, "https://ingestion.eu.bronto.io/v1/traces"},
  {otlp_headers, [{<<"x-bronto-api-key">>, <<"<YOUR_API_KEY>">>}]}
]}

Region	Logs endpoint	Traces endpoint
EU	`https://ingestion.eu.bronto.io/v1/logs`	`https://ingestion.eu.bronto.io/v1/traces`
US	`https://ingestion.us.bronto.io/v1/logs`	`https://ingestion.us.bronto.io/v1/traces`

See API Keys for how to create a key with ingestion permissions. No other changes to the rest of the setup are required.

Overview

Ingest with agents

Ingest from AWS

Ingest from Azure

Ingest from CDN and edge

Ingest from apps and platforms

Ingest from infrastructure and databases

Ingest OpenTelemetry data

Send Erlang and Elixir logs and traces to Bronto

Prerequisites

Install dependencies

Configure the log bridge

Set resource attributes

Complete example

Verify delivery

Traces

Configure tracing

Creating spans

GenAI semantic conventions

Direct export to Bronto

​Prerequisites

​Install dependencies

​Configure the log bridge

​Set resource attributes

​Complete example

​Verify delivery

​Traces

​Configure tracing

​Creating spans

​GenAI semantic conventions

​Direct export to Bronto

Prerequisites

Install dependencies

Configure the log bridge

Set resource attributes

Complete example

Verify delivery

Traces

Configure tracing

Creating spans

GenAI semantic conventions

Direct export to Bronto