duct

duct.aggregators

duct.aggregators.Counter(a, b, delta)

Counter derivative

duct.aggregators.Counter32(a, b, delta)

32bit counter aggregator with wrapping

duct.aggregators.Counter64(a, b, delta)

64bit counter aggregator with wrapping

duct.interfaces

duct.objects

class duct.objects.Event(state, service, description, metric, ttl, tags=None, hostname=None, aggregation=None, evtime=None, attributes=None, type='metric')

Bases: object

Duct Event object

All sources pass these to the queue, which form a proxy object to create protobuf Event objects

Parameters:

• state – Some sort of string < 255 chars describing the state
• service – The service name for this event
• description – A description for the event, ie. “My house is on fire!”
• metric – int or float metric for this event
• ttl – TTL (time-to-live) for this event
• tags – List of tag strings
• hostname – Hostname for the event (defaults to system fqdn)
• aggregation – Aggregation function
• attributes – A dictionary of key/value attributes for this event
• evtime – Event timestamp override

class duct.objects.Output(config, duct)

Bases: object

Output parent class

Outputs can inherit this object which provides a construct for a working output

Parameters:

• config – Dictionary config for this queue (usually read from the yaml configuration)
• duct – A DuctService object for interacting with the queue manager

createClient()

Deferred which sets up the output

eventsReceived(events)

Receives a list of events and queues them

Arguments: events – list of duct.objects.Event

stop()

Called when the service shuts down

class duct.objects.Source(config, queueBack, duct)

Bases: object

Source parent class

Sources can inherit this object which provides a number of utility methods.

Parameters:

• config – Dictionary config for this queue (usually read from the yaml configuration)
• queueBack – A callback method to recieve a list of Event objects
• duct – A DuctService object for interacting with the queue manager

createEvent(state, description, metric, prefix=None, hostname=None, aggregation=None, evtime=None)

Creates an Event object from the Source configuration

createLog(type, data, evtime=None, hostname=None)

Creates an Event object from the Source configuration

startTimer(*args, **kwargs)

Starts the timer for this source

stopTimer()

Stops the timer for this source

tick(*args, **kwargs)

Called for every timer tick. Calls self.get which can be a deferred and passes that result back to the queueBack method

Returns a deferred

duct.service

class duct.service.DuctService(config)

Bases: twisted.application.service.Service

Duct service

Runs timers, configures sources and and manages the queue

sendEvent(source, events)

Callback that all event sources call when they have a new event or list of events

setupOutputs(config)

Setup output processors

setupSources(config)

Sets up source objects from the given config

sourceWatchdog()

Watchdog timer function.

Recreates sources which have not generated events in 10*interval if they have watchdog set to true in their configuration

duct.utils

class duct.utils.BodyReceiver(finished)

Bases: twisted.internet.protocol.Protocol

Simple buffering consumer for body objects

class duct.utils.PersistentCache(location='/var/lib/duct/cache')

Bases: object

A very basic dictionary cache abstraction. Not to be used for large amounts of data or high concurrency

contains(k)

Return True if key k exists

delete(k)

Remove key k from the cache

expire(age)

Expire any items in the cache older than age seconds

get(k)

Returns key contents, and modify time

set(k, v)

Set a key k to value v

class duct.utils.ProcessProtocol(deferred, timeout)

Bases: twisted.internet.protocol.ProcessProtocol

ProcessProtocol which supports timeouts

class duct.utils.Resolver

Bases: object

Helper class for DNS resolution

class duct.utils.StringProducer(body)

Bases: object

String producer for writing to HTTP requests

exception duct.utils.Timeout

Bases: exceptions.Exception

Raised to notify that an operation exceeded its timeout.

duct.utils.fork(executable, args=(), env={}, path=None, timeout=3600)

Provides a deferred wrapper function with a timeout function

Parameters:

• executable (str.) – Executable
• args (tupple.) – Tupple of arguments
• env (dict.) – Environment dictionary
• timeout (int.) – Kill the child process if timeout is exceeded