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.

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

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.