After instantiating your logger, you can start sending counters and timers using the heka-node client.
Counters increment a named value. You may increment the counter by values other than 1, and you can take random samples instead of sending an increment message every time.
Typically, these messages go into statsd.
Signature
incr(name, opts={}, sample_rate=1.0)
The simplest way to increment a counter is to simply name the counter
log.incr(‘demo.node.incr_thing’);
Options:
The incr() method takes two optional arguments, an opts dictionary and a sample_rate.
name is the name of the counter you are incrementing.
The opts dictionary may include an integer count and dictionary fields. count represents the number to increment by in case you want to increase the counters by more than the default of 1.
fields is a dictionary of data. By default, heka-node will create this dictionary for you and autopopulate the name and sampling rate into the dictionary for you. If you supply fields, you can supply additional key value pairs to store into fields.
If the sample_rate is supplied, it must be a float from 0 to 1.0. heka-node will compute a random number. If the random number is greater than the sample_rate, then no message is delivered.
Note that because Javascript has only a single number type, you will need to use the heka.BoxedFloat type to ensure that the sample_rate is properly encoded into a double precision number to protect against a rate of 1.0 being encoded into an integer.
Example
log.incr('some_counter', {count: 2, my_meta: 42}, new heka.BoxedFloat(0.25))
Will send a message ~25% of the time to hekad. Each increment will increase the count of ‘some_counter’ by 2 and will also send a field ‘my_meta’ with a value of 42 to the server.
The timer method provides a way to decorate functions so that you will emit timing messages whenever the function is invoked.
Typically, these messages go into statsd.
Signature
timer(fn, name, opts={})
Options:
fn is the function to be called name is the name of the event you are measuring. opts may contain a rate attribute which specifies a sampling rate for timer messages.
The return value of timer is your decorated function.
Note that because Javascript has only a single number type, you will need to use the heka.BoxedFloat type to ensure that the rate is properly encoded into a double precision number to protect against a rate of 1.0 being encoded into an integer.
The heka wire format for 0.2 currently uses ProtocolBuffers to encode the header and you may use ProtocolBuffer or JSON to encode the payload.
At this time, please use the JSON encoder only. There are known bugs when the ProtocolBuffer encoder is applied to the payload of the message body.