The titan Log Engine

The titan Log Engine is in charge of fetching log messages from a kafka topic and providing it. It can be reached via a websocket connection.

Building/ running

To run the service simply use go run ./cmd/logengine

or to create an executable file go build ./cmd/logengine

It features the following command line arguments:

Name	Options (default)	Purpose
port	(9007)	Port on which the log service serves
log-level	info/debug/warning/error	Log level
	(info)
to-stdout	true/false (true)	Flag: set to true to print logs to stdout
config-file	(internal/app/logengine/config.yaml)	Configuration file
kafka	10.14.0.23:9092	URL of the Kafka broker ()
topic	titan.logs	Topic with the Titan logs in UJO format
log-to-kafka	(false)	Flag: use kafka hook for logging
service-topic	(titan.servicelogs)	kafka topic for logs

Generally, all settings listed above can be done also via environment variables, whereby the variables are composed of a prefix (TITAN_LE) and the argument using snake case:

TITAN_LE_ARGUMENT, e.g. TITAN_LE_LOG_LEVEL

Usage

Fetching log messages

Open a websocket connection to HOST:PORT. The Log Engine will send back log message objects as JSON objects until the connection is closed.

Unsubscribing from the Log Engine

You can unsubscribe from Log Engine by sending a json object:

{
"payload": "stop"
}

Filtering

To filter the log messages you need to send a json object with the key:value pairs of the Log message object you want to filter for, e.g.

{
"payload": { "Severity": "Info"}
}

Log message object

structure of a log message object is

Items:

Name	Type	Doc	Constraints
Timestamp	map	time stamp of creation
Severity	string	Severity level of the log message
Hostname	string	Name of the sending host
Servicename	string	Name of the sending service
Message	string	Log Message
FlowUID	string	UUID of the flow
BrickUID	string	UUID of the brick