Electric.Telemetry.OpenTelemetry (electric v1.0.23)
View SourceThis module implements an API to cover parts of the code with tracing spans that are then exported using the OpenTelemetry protocol.
OpenTelemetry is an observability framework that is widely supported by observability tools.
This module's implementation is based on the opentelemetry-erlang suite of libraries. There is a rudimentary Elixir API there but it's incomplete and non-idiomatic. The idea with this module is to expose all of the functionality we're using in our code by wrapping opentelemetry-erlang's API.
The configuration for OpenTelemetry export is located in config/runtime.exs
.
The API implemented here so far includes support for:
Defining a span to cover the execution of a piece of code. See
with_span/3
.Propagating span context across Elixir processes, to allow for a span started in one process to be registered as a parent of a span started in a different process. See
get_current_context/1
andset_current_context/1
.Adding dynamic attributes to the current span, after it has already started. See
add_span_attributes/2
.Recording an error or an exception as a span event. See
record_exception/4
.
Summary
Functions
Add dynamic attributes to the current span.
Removes the current interval timer from prcess memory and returns it.
Retrieve the telemetry span attributes from the persistent term for this stack.
Add an error event to the current span.
Set the interval timer for the current process.
Store the telemetry span attributes in the persistent term for this stack.
Records that an interval with the given interval_name
has started.
Records the interval timings as attributes in the current span and wipes the interval timer from process memory.
Executes the provided function and records its duration in microseconds.
The duration is added to the current span as a span attribute named with the given name
.
Wipe the current interval timer from process memory.
Create a span that starts at the current point in time and ends when fun
returns.
Functions
@spec add_span_attributes(span_ctx() | nil, span_attrs()) :: boolean()
Add dynamic attributes to the current span.
For example, if a span is started prior to issuing a DB request, an attribute named
num_rows_fetched
can be added to it using this function once the DB query returns its
result.
@spec extract_interval_timer() :: Electric.Telemetry.IntervalTimer.t()
Removes the current interval timer from prcess memory and returns it.
Useful if you want to time intervals over multiple processes,
extract the timer, pass it to another process, and then
use set_interval_timer/1
to restore it in the new process.
Retrieve the telemetry span attributes from the persistent term for this stack.
Add an error event to the current span.
@spec set_interval_timer(Electric.Telemetry.IntervalTimer.t()) :: :ok
Set the interval timer for the current process.
@spec set_stack_span_attrs(String.t(), span_attrs()) :: :ok
Store the telemetry span attributes in the persistent term for this stack.
@spec start_interval(binary()) :: :ok
Records that an interval with the given interval_name
has started.
This is useful if you want to find out which part of a process took the longest time. It works out simpler than wrapping each part of the process in a timer, and guarentees no gaps in the timings.
Once a number of intervals have been started, call
stop_and_save_intervals()
to record the interval timings as
attributes in the current span.
e.g.
OpenTelemetry.start_interval("quick_sleep")
Process.sleep(1)
OpenTelemetry.start_interval("longer_sleep")
Process.sleep(2)
OpenTelemetry.stop_and_save_intervals(total_attribute: "total_sleep_µs")
will add the following attributes to the current span: quick_sleep.duration_µs: 1000 longer_sleep.duration_µs: 2000 total_sleep_µs: 3000
Records the interval timings as attributes in the current span and wipes the interval timer from process memory.
Options:
:timer
- the interval timer to use. If not provided, the timer is extracted from the process memory.:total_attribute
- the name of the attribute to store the total time across all intervals. If not provided no total time is recorded.
Executes the provided function and records its duration in microseconds.
The duration is added to the current span as a span attribute named with the given name
.
Wipe the current interval timer from process memory.
Create a span that starts at the current point in time and ends when fun
returns.
Returns the result of calling the function fun
.
Calling this function inside another span establishes a parent-child relationship between
the two, as long as both calls happen within the same Elixir process. Use get_current_context/1
for
interprocess progragation of span context.
The stack_id
parameter must be set in root spans. For child spans the stack_id is optional
and will be inherited from the parent span.