Flush API in Mobile SDKs

This guide walks you through the flush API and the different event flushing policies supported by the RudderStack Kotlin and Swift SDKs.

Overview

The RudderStack Kotlin and Swift SDKs provide a flush API that lets you manually flush any stored events irrespective of the configured flush policies.

You can trigger a flush API call as follows:

analytics.flush()

analytics.flush();

analytics.flush()

[analytics flush];

If you have added a mobile device mode integration plugin, then a flush API call will also trigger the integration’s flush API, if it is supported.

Flush policies

RudderStack supports three configurable flush policies. By default, all three policies are enabled.

Count flush policy

The CountFlushPolicy triggers a flush call when a predefined threshold for the event count is reached.

Frequency flush policy

The FrequencyFlushPolicy automatically triggers a flush at the specified intervals.

Startup flush policy

The StartupFlushPolicy automatically triggers a one-time flush API call after the Kotlin SDK is initialized.

Set a flush policy

You can select and set a flush policy depending on your use case.

Selecting a flush policy from the provided list overrides the default flush policy.

The following examples highlight how you can set the FrequencyFlushPolicy in the Kotlin and Swift SDKs:

Kotlin

1. Import the flush policy as shown:

import com.rudderstack.sdk.kotlin.core.internals.policies.FrequencyFlushPolicy

2. Add FrequencyFlushPolicy during the SDK initialization, as shown below. Replace the WRITE_KEY and DATA_PLANE_URL parameters in the below snippet with the Kotlin source write key and your data plane URL.

analytics = Analytics(
    configuration = Configuration(
        writeKey = BuildConfig.WRITE_KEY,
        application = application,
        dataPlaneUrl = BuildConfig.DATA_PLANE_URL,
        flushPolicies = listOf(
            FrequencyFlushPolicy()
        )
    )
)

The corresponding Java snippet is shown below:

FrequencyFlushPolicy frequencyFlushPolicy = new FrequencyFlushPolicy();
ArrayList<FlushPolicy> listOfFlushPolicies = new ArrayList<>();
listOfFlushPolicies.add(frequencyFlushPolicy);

Configuration configuration = new ConfigurationBuilder(this, "WRITE_KEY", "DATA_PLANE_URL")
        .setFlushPolicies(listOfFlushPolicies)
        .build();

analytics = new JavaAnalytics(configuration);

Swift

import RudderStackAnalytics

self.analytics = Analytics(configuration: Configuration(
    writeKey: "<WRITE_KEY>",
    dataPlaneUrl: "<DATA_PLANE_URL>",
    flushPolicies: [
        FrequencyFlushPolicy()
    ]
))

@import RudderStackAnalytics;

RSSConfigurationBuilder *builder = [[RSSConfigurationBuilder alloc]
    initWithWriteKey:@"<WRITE_KEY>"
       dataPlaneUrl:@"<DATA_PLANE_URL>"];

[builder setFlushPolicies:@[
    [RSSFrequencyFlushPolicy new]
]];

RSSAnalytics *analytics = [[RSSAnalytics alloc]
    initWithConfiguration:[builder build]];

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