metrex v0.2.1 Metrex.Meter
Meter metrics implementation. Timeseries counter approach to increment, decrement using unixtime stamp.
Examples
Static meters:
Add list of meters into config.exs file to autostart meters:
config :metrex,
meters: ["pageviews"],
ttl: 900
On-demand meters:
To create on-demand meters, you need to call start_link
function:
# Initialize meter with []
Metrex.start_meter("special_clicks")
Meter operations:
Meter operations are increment, decrement, count and dump:
# Increment a meter by 1
Metrex.Meter.increment("pageviews")
# Increment a meter by x(number)
Metrex.Meter.increment("pageviews", 5)
# Decrement a meter by 1
Metrex.Meter.decrement("pageviews")
# Decrement a meter by x(number)
Metrex.Meter.decrement("pageviews", 3)
# Get meter for unixtime
Metrex.Meter.count("pageviews", 1475452816)
# Dump meter map related to a metric
Metrex.Meter.dump("pageviews")
Link to this section Summary
Functions
Returns a specification to start this module under a supervisor.
Display current counter at given time
Decrement metric by given val
Return all metric data
Increment metric by given val
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
Remove metric at the time
Reset all the metric data
Start a new Meter
metric
Link to this section Functions
child_spec(init_arg)
Returns a specification to start this module under a supervisor.
See Supervisor
.
count(metric, time)
Display current counter at given time
decrement(metric, val \\ 1)
Decrement metric by given val
dump(metric)
Return all metric data
increment(metric, val \\ 1)
Increment metric by given val
init(val)
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
init_arg
is the argument term (second argument) passed to start_link/3
.
Returning {:ok, state}
will cause start_link/3
to return
{:ok, pid}
and the process to enter its loop.
Returning {:ok, state, timeout}
is similar to {:ok, state}
except handle_info(:timeout, state)
will be called after timeout
milliseconds if no messages are received within the timeout.
Returning {:ok, state, :hibernate}
is similar to {:ok, state}
except the process is hibernated before entering the loop. See
c:handle_call/3
for more information on hibernation.
Returning {:ok, state, {:continue, continue}}
is similar to
{:ok, state}
except that immediately after entering the loop
the c:handle_continue/2
callback will be invoked with the value
continue
as first argument.
Returning :ignore
will cause start_link/3
to return :ignore
and
the process will exit normally without entering the loop or calling
c:terminate/2
. If used when part of a supervision tree the parent
supervisor will not fail to start nor immediately try to restart the
GenServer
. The remainder of the supervision tree will be started
and so the GenServer
should not be required by other processes.
It can be started later with Supervisor.restart_child/2
as the child
specification is saved in the parent supervisor. The main use cases for
this are:
- The
GenServer
is disabled by configuration but might be enabled later. - An error occurred and it will be handled by a different mechanism than the
Supervisor
. Likely this approach involves callingSupervisor.restart_child/2
after a delay to attempt a restart.
Returning {:stop, reason}
will cause start_link/3
to return
{:error, reason}
and the process to exit with reason reason
without
entering the loop or calling c:terminate/2
.
Callback implementation for GenServer.init/1
.
remove(metric, time)
Remove metric at the time
reset(metric)
Reset all the metric data
start_link(metric)
Start a new Meter
metric