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

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child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

Link to this function

count(metric, time)

Display current counter at given time

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decrement(metric, val \\ 1)

Decrement metric by given val

Return all metric data

Link to this function

increment(metric, val \\ 1)

Increment metric by given 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 calling Supervisor.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.

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remove(metric, time)

Remove metric at the time

Reset all the metric data

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start_link(metric)

Start a new Meter metric