further_reading.md

Further Reading

Covers advanced topics (different config options and scenarios)

Configuration Options

The following configuration options are available to control the behaviour of the SDK. You can configure the URLs used to connect to Harness via the Connector config. The reast of the configuration is part of the BaseConfig.

// Connector Config
HarnessConfig connectorConfig = HarnessConfig.builder()
        .configUrl("https://config.ff.harness.io/api/1.0")
        .eventUrl("https://config.ff.harness.io/api/1.0")
        .build();

// Create Options
BaseConfig options = BaseConfig.builder()
        .pollIntervalInSeconds(60)
        .streamEnabled(true)
        .analyticsEnabled(true)
        .build();

// Create the client
CfClient cfClient = new CfClient(new HarnessConnector(apiKey, connectorConfig), options);

Name	Config Option	Description	default
baseUrl	HarnessConfig.configUrl("https://config.ff.harness.io/api/1.0")	the URL used to fetch feature flag evaluations. You should change this when using the Feature Flag proxy to http://localhost:7000	https://config.ff.harness.io/api/1.0
eventsUrl	HarnessConfig.eventUrl("https://config.ff.harness.io/api/1.0"),	the URL used to post metrics data to the feature flag service. You should change this when using the Feature Flag proxy to http://localhost:7000	https://events.ff.harness.io/api/1.0
pollInterval	BaseConfig.pollIntervalInSeconds(60))	when running in stream mode, the interval in seconds that we poll for changes.	60
enableStream	BaseConfig.streamEnabled(false)	Enable streaming mode.	true
enableAnalytics	BaseConfig.analyticsEnabled(true)	Enable analytics. Metrics data is posted every 60s	true

Logging Configuration

You can provide your own logger to the SDK and configure it using the standard logging configuration. For example if using Log4j you can add the following log4j2.xml to your project to enable debug.

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO" monitorInterval="30">
    <Properties>
        <Property name="LOG_PATTERN">%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1} SDK=${sys:SDK} flag=${sys:version} target=%mdc{target} - %m%n</Property>
    </Properties>

    <Appenders>
        <Console name="console" target="SYSTEM_OUT" follow="true">
            <PatternLayout pattern="${LOG_PATTERN}"/>
        </Console>
    </Appenders>

    <Loggers>
        <Root level="debug">
            <AppenderRef ref="console"/>
        </Root>
    </Loggers>
</Configuration>

Recommended reading

Feature Flag Concepts

Feature Flag SDK Concepts

Setting up your Feature Flags

Feature Flags Getting Started

Other Variation Types

Bool Variation

boolean result = cfClient.boolVariation("sample_boolean_flag", target, false);

Number Variation

boolean result = cfClient.numberVariation("sample_number_flag", target, 0);

String Variation

boolean result = cfClient.stringVariation("sample_string_flag", target, "");

MultiVariate Examples

double number = cfClient.numberVariation(COUNT_FEATURE_KEY, parentTarget, 1);
        String color = cfClient.stringVariation(COLOR_FEATURE_KEY, target, "black");

Example log4j file

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30">
    <Properties>
        <Property name="LOG_PATTERN">%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1} SDK=${sys:SDK} flag=${sys:version} target=%mdc{target} - %m%n</Property>
    </Properties>

    <Appenders>
        <Console name="console" target="SYSTEM_OUT" follow="true">
            <PatternLayout pattern="${LOG_PATTERN}"/>
        </Console>
    </Appenders>

    <Loggers>
        <Root level="info">
            <AppenderRef ref="console"/>
        </Root>
    </Loggers>
</Configuration>

Cleanup

To avoid potential memory leak, when SDK is no longer needed (when the app is closed, for example), a caller should call this method:

cfClient.close();

Change default URL

When using your Feature Flag SDKs with a Harness Relay Proxy you need to change the default URL.