com.launchdarkly.client.files

Class FileComponents

java.lang.Object

com.launchdarkly.client.files.FileComponents

public abstract class FileComponents
extends java.lang.Object

The entry point for the file data source, which allows you to use local files as a source of feature flag state. This would typically be used in a test environment, to operate using a predetermined feature flag state without an actual LaunchDarkly connection.

To use this component, call fileDataSource() to obtain a factory object, call one or methods to configure it, and then add it to your LaunchDarkly client configuration. At a minimum, you will want to call FileDataSourceFactory.filePaths(String...) to specify your data file(s); you can also use FileDataSourceFactory.autoUpdate(boolean) to specify that flags should be reloaded when a file is modified. See FileDataSourceFactory for all configuration options.

     FileDataSourceFactory f = FileComponents.fileDataSource()
         .filePaths("./testData/flags.json")
         .autoUpdate(true);
     LDConfig config = new LDConfig.Builder()
         .updateProcessorFactory(f)
         .build();
 

This will cause the client not to connect to LaunchDarkly to get feature flags. The client may still make network connections to send analytics events, unless you have disabled this with LDConfig.Builder.sendEvents(boolean) or LDConfig.Builder.offline(boolean).

Flag data files can be either JSON or YAML. They contain an object with three possible properties:

• flags: Feature flag definitions.
• flagVersions: Simplified feature flags that contain only a value.
• segments: User segment definitions.

The format of the data in flags and segments is defined by the LaunchDarkly application and is subject to change. Rather than trying to construct these objects yourself, it is simpler to request existing flags directly from the LaunchDarkly server in JSON format, and use this output as the starting point for your file. In Linux you would do this:

     curl -H "Authorization: {your sdk key}" https://app.launchdarkly.com/sdk/latest-all
 

The output will look something like this (but with many more properties):

 {
     "flags": {
         "flag-key-1": {
             "key": "flag-key-1",
             "on": true,
             "variations": [ "a", "b" ]
         },
         "flag-key-2": {
             "key": "flag-key-2",
             "on": true,
             "variations": [ "c", "d" ]
         }
     },
     "segments": {
         "segment-key-1": {
             "key": "segment-key-1",
             "includes": [ "user-key-1" ]
         }
     }
 }
 

Data in this format allows the SDK to exactly duplicate all the kinds of flag behavior supported by LaunchDarkly. However, in many cases you will not need this complexity, but will just want to set specific flag keys to specific values. For that, you can use a much simpler format:

 {
     "flagValues": {
         "my-string-flag-key": "value-1",
         "my-boolean-flag-key": true,
         "my-integer-flag-key": 3
     }
 }
 

Or, in YAML:

 flagValues:
   my-string-flag-key: "value-1"
   my-boolean-flag-key: true
   my-integer-flag-key: 3
 

It is also possible to specify both flags and flagValues, if you want some flags to have simple values and others to have complex behavior. However, it is an error to use the same flag key or segment key more than once, either in a single file or across multiple files.

If the data source encounters any error in any file-- malformed content, a missing file, or a duplicate key-- it will not load flags from any of the files.

Since:

4.5.0

Constructor Summary

Constructors

Constructor and Description
FileComponents()

Method Summary

Modifier and Type	Method and Description
static FileDataSourceFactory	fileDataSource() Creates a FileDataSourceFactory which you can use to configure the file data source.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FileComponents

public FileComponents()

Method Detail

fileDataSource

public static FileDataSourceFactory fileDataSource()

Creates a FileDataSourceFactory which you can use to configure the file data source.

Returns:

a FileDataSourceFactory