Library for localized telemetry metrics
def deps do
[
{:mobius, "~> 0.4.0"}
]
endAdd Mobius to your supervision tree and pass in the metrics you want to track.
def start(_type, _args) do
metrics = [
Metrics.last_value("my.telemetry.event"),
]
children = [
# ... other children ....
{Mobius, metrics: metrics}
# ... other children ....
]
# See https://hexdocs.pm/elixir/Supervisor.html
# for other strategies and supported options
opts = [strategy: :one_for_one, name: MyApp.Supervisor]
Supervisor.start_link(children, opts)
endTo see a view of the current metrics you can use Mobius.info/0:
iex> Mobius.info()
Metric Name: vm.memory.total
Tags: %{}
last_value: 83952736To plot a metric measurement over time you can use: Mobius.Exports.plot/4:
iex> Mobius.Exports.plot("vm.memory.total", :last_value, %{})
Metric Name: vm.memory.total, Tags: %{}
34355808.00 ┤
34253736.73 ┤ ╭──╮ ╭────╮
34151665.45 ┤ ╭────╯ ╰────╯ ╰───
34049594.18 ┤ ╭────╮ ╭────╮ ╭────╯
33947522.91 ┤ │ ╰────╯ ╰─╯
33845451.64 ┤ │
33743380.36 ┤ ╭────╯
33641309.09 ┤ │
33539237.82 ┤ │
33437166.55 ┤ │
33335095.27 ┼────╯By default Mobius will try to save metric data for all resolutions and the
current value when the erlang system exists gracefully. This makes Mobius useful
for Nerves devices that have to reboot after doing a planned firmware update.
The default direction Mobius will try to persist data to is the /data
directory as this is friendly to Nerves devices. If you want Mobius to store
data in a different location you can pass that into Mobius when you start it:
children = [
# ... other children ...
{Mobius, metrics: metrics(), persistence_dir: "/tmp"}
# ... other children ...
]
def metrics() do
[
Metrics.last_value("vm.memory.total", unit: {:byte, :kilobyte})
]
endBy default the metrics data is persisted on a normal shutdown. However, data will not be persisted during a sudden shutdown, eg Control-C in IEX, kill, sudden power off.
It's possible to manually call Mobius.save/1 to force an interim write of the persistence data.
This can be automated by passing autosave_interval to Mobius
def start(_type, _args) do
metrics = [
Metrics.last_value("my.telemetry.event"),
]
children = [
# ... other children ....
{Mobius, metrics: metrics, autosave_interval: 60} # auto save every 60 seconds
# ... other children ....
]
# See https://hexdocs.pm/elixir/Supervisor.html
# for other strategies and supported options
opts = [strategy: :one_for_one, name: MyApp.Supervisor]
Supervisor.start_link(children, opts)
endThe Mobius.Exports module provide functions for exporting the data in a couple
different formats.
- CSV
- Series
- Line plot
- Mobius Binary Format
# export as CSV string
Mobius.Exports.csv("vm.memory.total", :last_value, %{})
# export as series list
Mobius.Exports.series("vm.memory.total", :last_value, %{})
# export as mobius binary format
Mobius.Exports.mbf()The Mobius Binary Format (MBF) is a binary string that has encoded and
compressed the all the historical metrics that mobius current has. This is
most useful for preparing metrics to send off to another system. To parse
the binary format you can use Mobius.Exports.parse_mbf/1.
For each of these you can see the Mobius.Exports module for more details.