ChannelClient.
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Telemetry events emitted by ChannelClient.
ChannelClient instruments its connection, message flow and channel
operations with :telemetry spans and
point events. Attach handlers to build metrics or traces — the
start/stop/exception triples follow :telemetry.span conventions
so APM agents (LiveDashboard, AppSignal, OpenTelemetry converters, etc.)
can turn them into spans directly.
No payload contents are ever included in event metadata; only topics, events names, refs and sizes.
Event catalog
| Event | Measurements | Metadata | Description |
|---|---|---|---|
[:channel_client, :connection, :start] | %{system_time} | %{transport, url} | A transport open attempt began |
[:channel_client, :connection, :stop] | %{duration} | %{transport, url, result} (result: :ok | :error, plus reason on error) | Open attempt finished |
[:channel_client, :connection, :disconnected] | %{} | %{reason} | The transport reported a disconnect |
[:channel_client, :message, :out] | %{payload_bytes} | %{topic, event, ref} | An encoded frame was queued for sending |
[:channel_client, :message, :in] | %{duration, payload_bytes} | %{topic, event, ref, join_ref} | A server frame was decoded |
[:channel_client, :channel_join, :start] | %{system_time} | %{topic} | ChannelClient.Channel.join/3,4 began (client side) |
[:channel_client, :channel_join, :stop] | %{duration} | %{topic, result} (+ reason) | Join finished; result: :ok or :error |
[:channel_client, :push, :start] | %{system_time} | %{event} | A synchronous push/4 began awaiting a reply |
[:channel_client, :push, :stop] | %{duration} | %{event, result} (+ reason) | Reply arrived; result: :ok or :error |
[:channel_client, :push, :exception] | %{duration} | %{event, kind, reason, stacktrace} | A push crashed or timed out |
duration values are in native time units; convert with
System.convert_time_unit/3.
Example
:telemetry.attach(
"log-connections",
[:channel_client, :connection, :stop],
fn _name, measurements, metadata, _config ->
Logger.info("connected=#{inspect(metadata.result)}")
end,
nil
)Summary
Functions
@spec events() :: [[atom(), ...]]
Returns all event names emitted by ChannelClient.