Class FileData

Integration between the LaunchDarkly SDK and file data.

Inheritance

object

FileData

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: LaunchDarkly.Sdk.Server.Integrations

Assembly: LaunchDarkly.ServerSdk.dll

Syntax

public static class FileData

Remarks

The file data source 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. See DataSource() for details.

This is different from {@link TestData}, which allows you to simulate flag configurations programmatically rather than using a file.

Methods

DataSource()

Creates a builder for configuring the file data source.

Declaration

public static FileDataSourceBuilder DataSource()

Returns

Type	Description
FileDataSourceBuilder	a FileDataSourceBuilder

Remarks

To use this component, call DataSource() 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 FilePaths(params string[]) to specify your data file(s); you can also use AutoUpdate(bool) to specify that flags should be reloaded when a file is modified. See FileDataSourceBuilder for all configuration options.

var fileSource = FileData.DataSource()
    .FilePaths("./testData/flags.json")
    .AutoUpdate(true);
var config = Configuration.Builder("sdkKey")
    .DataSource(fileSource)
    .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 configuration.EventProcessor(Components.NullEventProcessor).

Flag data files are JSON by default (although it is possible to specify a parser for another format, such as YAML; see Parser(Func<string, object>)). They contain an object with three possible properties:

• flags: Feature flag definitions.
• flagVersions: Simplified feature flags that contain only a value.
• segments: 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://sdk.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" ]
        }
    },
    "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
    }
}

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.

See Also

TestData