View Source Membrane.Telemetry (Membrane Core v1.0.1)
Defines basic telemetry event types used by Membrane's Core.
Membrane uses Telemetry Package for instrumentation and does not store or save any measurements by itself.
It is user's responsibility to use some sort of metrics reporter
that will be attached to :telemetry package to consume and process generated measurements.
Instrumentation
The following events are published by Membrane's Core with following measurement types and metadata:
[:membrane, :metric, :value]- used to report metrics, such as input buffer's size inside functions, incoming events and received stream format- Measurement:
metric_event_value/0 - Metadata:
%{}
- Measurement:
[:membrane, :link, :new]- to report new link connection being initialized in pipeline.- Measurement:
link_event_value/0 - Metadata:
%{}
- Measurement:
[:membrane, :pipeline | :bin | :element, :init]- to report pipeline/element/bin initialization- Measurement:
init_or_terminate_event_value/0 - Metadata:
%{log_metadata: keyword()}, includes Logger's metadata of created component
- Measurement:
[:membrane, :pipeline | :bin | :element, :terminate]- to report pipeline/element/bin termination- Measurement:
init_or_terminate_event_value/0 - Metadata:
%{}
- Measurement:
Enabling certain metrics/events
A lot of events can happen literally hundreds times per second such as registering that a buffer has been sent/processed.
This behaviour can come with a great performance penalties but may be helpful for certain discoveries. To avoid any runtime overhead
when the reporting is not necessary all metrics/events are hidden behind a compile-time feature flags.
To enable a particular measurement one must recompile membrane core with the following snippet put inside
user's application config.exs file:
config :membrane_core,
telemetry_flags: [
:flag_name,
...,
{:metrics, [list of metrics]}
...
]Available flags are (those are of a very low overhead):
:links- enables new links notifications:inits_and_terminates- enables notifications ofinitandterminateevents for elements/bins/pipelines
Additionally one can control which metric values should get measured by passing an option of format :
{:metrics, [list of metrics]}
Available metrics are:
:buffer- number of buffers being sent from a particular element:bitrate- total number of bits carried by the buffers mentioned above:queue_len- number of messages in element's message queue during GenServer'shandle_infoinvocation:stream_format- indicates that given element has received new stream format, value always equals '1':event- indicates that given element has received a new event, value always equals '1':store- reports the current size of a input buffer when storing a new buffer:take_and_demand- reports the current size of a input buffer when taking buffers and making a new demand
Summary
Types
- path - element's path
- parent_path - process path of link's parent
- from - from element name
- to - to element name
- pad_from - from's pad name
- pad_to - to's pad name
- component_path - element's or bin's path
- metric - metric's name
- value - metric's value
Types
@type event_name() :: [atom(), ...]
@type init_or_terminate_event_value() :: %{path: Membrane.ComponentPath.path()}
- path - element's path
@type link_event_value() :: %{ parent_path: String.t(), from: String.t(), to: String.t(), pad_from: String.t(), pad_to: String.t() }
- parent_path - process path of link's parent
- from - from element name
- to - to element name
- pad_from - from's pad name
- pad_to - to's pad name
- component_path - element's or bin's path
- metric - metric's name
- value - metric's value