fettle v0.1.0 Fettle.Application View Source
The Fettle
supervisor starts two servers; Fettle.ScoreBoard
a
GenServer
which responds to queries about the current health status,
and Fettle.RunnerSupervisor
a supervisor which starts worker Fettle.Runner
servers
running the health-checks themselves, and takes care of restarting them if they
exit abnormally.
The RunnerSupervisor
starts a worker process for each configured
Health.Spec
, configuring them so they report results back to
the ScoreBoard
process.
:fettle OTP app supervisor
- Fettle.ScoreBoard
Fettle.RunnerSupervisor
- Fettle.Runner
Link to this section Summary
Functions
Called when an application is started
Link to this section Functions
Called when an application is started.
This function is called when an the application is started using
Application.start/2
(and functions on top of that, such as
Application.ensure_started/2
). This function should start the top-level
process of the application (which should be the top supervisor of the
application’s supervision tree if the application follows the OTP design
principles around supervision).
start_type
defines how the application is started:
:normal
- used if the startup is a normal startup or if the application is distributed and is started on the current node because of a failover from another mode and the application specification key:start_phases
is:undefined
.{:takeover, node}
- used if the application is distributed and is started on the current node because of a failover on the nodenode
.{:failover, node}
- used if the application is distributed and is started on the current node because of a failover on nodenode
, and the application specification key:start_phases
is not:undefined
.
start_args
are the arguments passed to the application in the :mod
specification key (e.g., mod: {MyApp, [:my_args]}
).
This function should either return {:ok, pid}
or {:ok, pid, state}
if
startup is successful. pid
should be the PID of the top supervisor. state
can be an arbitrary term, and if omitted will default to []
; if the
application is later stopped, state
is passed to the stop/1
callback (see
the documentation for the c:stop/1
callback for more information).
use Application
provides no default implementation for the start/2
callback.
Callback implementation for Application.start/2
.