loggregator_consumer

README

#loggregator_consumer

Loggregator consumer is a library that allows an application developer to set up a connection to a loggregator server, and begin receiving log messages from it. It includes the ability to tail logs as well as get the recent logs.

#WARNING This library does not work with Go 1.3 through 1.3.2, due to a bug in the standard libraries.

Usage

See the included sample application. In order to use the sample, you will have to export the following environment variables:

• CF_ACCESS_TOKEN - You can get this value from reading the AccessToken looking at your cf configuration file ($ cat ~/.cf/config.json). Example:

export CF_ACCESS_TOKEN="bearer eyJhbGciOiJSUzI1NiJ9.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.mAaOJthCotW763lf9fysygqdES_Mz1KFQ3HneKbwY4VJx-ARuxxiLh8l_8Srx7NJBwGlyEtfYOCBcIdvyeDCiQ0wT78Zw7ZJYFjnJ5-ZkDy5NbMqHbImDFkHRnPzKFjJHip39jyjAZpkFcrZ8_pUD8XxZraqJ4zEf6LFdAHKFBM"

* APP_GUID - You can get this value from running `$ CF_TRACE=true cf app dora` and then extracting the app guid from the request URL. Example:

export APP_GUID=55fdb274-d6c9-4b8c-9b1f-9b7e7f3a346c

Then you can run the sample app like this:

export GOPATH=pwd export PATH=$PATH:$GOPATH/bin go get github.com/cloudfoundry/loggregator_consumer/sample_consumer sample_consumer

Development
-----------------

Use `go get -d -v -t ./... && ginkgo --race --randomizeAllSpecs --failOnPending --skipMeasurements --cover` to
run the tests.

Documentation

Overview

Package loggregator_consumer provides a simple, channel-based API for clients to communicate with loggregator servers.

Index

• Variables
• func SortRecent(messages []*logmessage.LogMessage) []*logmessage.LogMessage
• type DebugPrinter
• type LoggregatorConsumer
  • func New(endpoint string, tlsConfig *tls.Config, ...) LoggregatorConsumer

Variables

var (
	// KeepAlive sets the interval between keep-alive messages sent by the client to loggregator.
	KeepAlive = 25 * time.Second

	ErrNotFound    = errors.New("/recent path not found or has issues")
	ErrBadResponse = errors.New("bad server response")
	ErrBadRequest  = errors.New("bad client request")
)

Functions

func SortRecent

func SortRecent(messages []*logmessage.LogMessage) []*logmessage.LogMessage

SortRecent sorts a slice of LogMessages by timestamp. The sort is stable, so messages with the same timestamp are sorted in the order that they are received.

The input slice is sorted; the return value is simply a pointer to the same slice.

Types

type DebugPrinter

type DebugPrinter interface {
	Print(title, dump string)
}

type LoggregatorConsumer

type LoggregatorConsumer interface {

	//	Tail listens indefinitely for log messages. It returns two channels; the first is populated
	//	with log messages, while the second contains errors (e.g. from parsing messages). It returns
	//	immediately. Call Close() to terminate the connection when you are finished listening.
	//
	//	Messages are presented in the order received from the loggregator server. Chronological or
	//	other ordering is not guaranteed. It is the responsibility of the consumer of these channels
	//	to provide any desired sorting mechanism.
	Tail(appGuid string, authToken string) (<-chan *logmessage.LogMessage, error)

	//	Recent connects to loggregator via its 'recent' endpoint and returns a slice of recent messages.
	//	It does not guarantee any order of the messages; they are in the order returned by loggregator.
	//
	//	The SortRecent method is provided to sort the data returned by this method.
	Recent(appGuid string, authToken string) ([]*logmessage.LogMessage, error)

	// Close terminates the websocket connection to loggregator.
	Close() error

	// SetOnConnectCallback sets a callback function to be called with the websocket connection is established.
	SetOnConnectCallback(func())

	// SetDebugPrinter enables logging of the websocket handshake
	SetDebugPrinter(DebugPrinter)
}

LoggregatorConsumer represents the actions that can be performed against a loggregator server.

func New

func New(endpoint string, tlsConfig *tls.Config, proxy func(*http.Request) (*url.URL, error)) LoggregatorConsumer

New creates a new consumer to a loggregator endpoint.