@ohos.hiviewdfx.hiAppEvent (Application Event Logging)

The hiAppEvent module provides application event-related functions, including flushing application events to a disk, querying and clearing application events, and customizing application event logging configuration.

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import hiAppEvent from '@ohos.hiviewdfx.hiAppEvent';

hiAppEvent.addProcessor11+

addProcessor(processor: Processor): number

Adds a data processor for migrating events to the cloud. The implementation of data processors can be preset in the device. You can set attributes of the data processor based on its constraints.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
processor Processor Yes Data processor.

Return value

Type Description
number ID of the data processor to be added. If the operation fails, -1 is returned. If the operation is successful, a value greater than 0 is returned.

Error codes

ID Error Message
401 Parameter error.

Example

import hilog from '@ohos.hilog';

try {
    let processor: hiAppEvent.Processor = {
      name: 'analytics_demo'
    };
    let id: number = hiAppEvent.addProcessor(processor);
    hilog.info(0x0000, 'hiAppEvent', `addProcessor event was successful, id=${id}`);
} catch (error) {
    hilog.error(0x0000, 'hiAppEvent', `failed to addProcessor event, code=${error.code}`);
}

Processor11+

Defines a data processor for reporting events.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
name string Yes Name of a data processor. The value is string that contains a maximum of 256 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must not start with a digit.
debugMode boolean No Whether to enable the debug mode. The default value is false. The value true means to enable the debugging mode, and the value false means the opposite.
routeInfo string No Server location information. It is left empty by default. The length of the input string cannot exceed 8 KB. If the length exceeds 8 KB, the default value is used.
appId string No Application ID. It is left empty by default. The length of the input string cannot exceed 8 KB. If the length exceeds 8 KB, the default value is used.
onStartReport boolean No Whether to report an event when the data processor starts. The default value is false. The value true means to report events, and the value false means the opposite.
onBackgroundReport boolean No Whether to report an event when an application switches to the background. The default value is false. The value true means to report events, and the value false means the opposite.
periodReport number No Interval for event reporting, in seconds. The input value must be greater than or equal to 0. If the input value is less than 0, the default value 0 is used and periodic reporting is not performed.
batchReport number No Event reporting threshold. When the number of events reaches the threshold, an event is reported. The value must be greater than 0 and less than 1000. If the value is not within the range, the default value 0 is used and no events are reported.
userIds string[] No Name array of user IDs that can be reported by the data processor. name corresponds to the name parameter of the setUserId API.
userProperties string[] No Name array of user properties that can be reported by the data processor. name corresponds to the name parameter of the setUserProperty API.
eventConfigs AppEventReportConfig[] No Array of events that can be reported by the data processor.

AppEventReportConfig11+

Description of events that can be reported by the data processor.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
domain string No Event domain. The value is a string of up to 16 characters, including digits (0 to 9), letters (a to z), and underscores (_). It must start with a lowercase letter and cannot end with an underscore (_).
name string No Event name. The value is string that contains a maximum of 48 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must start with a letter or dollar sign ($) and end with a digit or letter.
isRealTime boolean No Whether to report events in real time. The value true means to report events, and the value false means the opposite.

hiAppEvent.removeProcessor11+

removeProcessor(id: number): void

Removes a data processor.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
id number Yes ID of a data processor. The value must be greater than 0.

Error codes

ID Error Message
401 Parameter error.

Example

import hilog from '@ohos.hilog';

try {
    let processor: hiAppEvent.Processor = {
      name: 'analytics_demo'
    };
    let id: number = hiAppEvent.addProcessor(processor);
    hiAppEvent.removeProcessor(id);
} catch (error) {
    hilog.error(0x0000, 'hiAppEvent', `failed to removeProcessor event, code=${error.code}`);
}

hiAppEvent.write

write(info: AppEventInfo, callback: AsyncCallback<void>): void

Writes events to the event file of the current day through AppEventInfo objects. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
info AppEventInfo Yes Application event object.
callback AsyncCallback<void> Yes Callback used to return the result.

Error codes

For details about the error codes, see Application Event Logging Error Codes.

ID Error Message
11100001 Function is disabled.
11101001 Invalid event domain.
11101002 Invalid event name.
11101003 Invalid number of event parameters.
11101004 Invalid string length of the event parameter.
11101005 Invalid event parameter name.
11101006 Invalid array length of the event parameter.

Example

import { BusinessError } from '@ohos.base';
import hilog from '@ohos.hilog';

let eventParams: Record<string, number | string> = {
  "int_data": 100,
  "str_data": "strValue",
};
hiAppEvent.write({
  domain: "test_domain",
  name: "test_event",
  eventType: hiAppEvent.EventType.FAULT,
  params: eventParams,
}, (err: BusinessError) => {
  if (err) {
    hilog.error(0x0000, 'hiAppEvent', `code: ${err.code}, message: ${err.message}`);
    return;
  }
  hilog.info(0x0000, 'hiAppEvent', `success to write event`);
});

hiAppEvent.write

write(info: AppEventInfo): Promise<void>

Writes events to the event file of the current day through AppEventInfo objects. This API uses a promise to return the result.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
info AppEventInfo Yes Application event object.

Return value

Type Description
Promise<void> Promise used to return the result.

Error codes

For details about the error codes, see Application Event Logging Error Codes.

ID Error Message
11100001 Function is disabled.
11101001 Invalid event domain.
11101002 Invalid event name.
11101003 Invalid number of event parameters.
11101004 Invalid string length of the event parameter.
11101005 Invalid event parameter name.
11101006 Invalid array length of the event parameter.

Example

import { BusinessError } from '@ohos.base';
import hilog from '@ohos.hilog';

let eventParams: Record<string, number | string> = {
  "int_data": 100,
  "str_data": "strValue",
};
hiAppEvent.write({
  domain: "test_domain",
  name: "test_event",
  eventType: hiAppEvent.EventType.FAULT,
  params: eventParams,
}).then(() => {
  hilog.info(0x0000, 'hiAppEvent', `success to write event`);
}).catch((err: BusinessError) => {
  hilog.error(0x0000, 'hiAppEvent', `code: ${err.code}, message: ${err.message}`);
});

AppEventInfo

Defines parameters for an AppEventInfo object.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
domain string Yes Event domain. The value is a string of up to 16 characters, including digits (0 to 9), letters (a to z), and underscores (_). It must start with a lowercase letter and cannot end with an underscore (_).
name string Yes Event name. The value is string that contains a maximum of 48 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must start with a letter or dollar sign ($) and end with a digit or letter.
eventType EventType Yes Event type.
params object Yes Event parameter object, which consists of a parameter name and a parameter value. The specifications are as follows:
- A parameter name is a string that contains a maximum of 16 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must start with a letter or dollar sign ($) and end with a digit or letter.
- The parameter value can be a string, number, boolean, or array. If the parameter value is a string, its maximum length is 8*1024 characters. If this limit is exceeded, excess characters will be discarded. If the parameter value is a number, the value must be within the range of Number.MIN_SAFE_INTEGER to Number.MAX_SAFE_INTEGER. Otherwise, uncertain values may be generated. If the parameter value is an array, the elements in the array must be of the same type, which can only be string, number, or boolean. In addition, the number of elements must be less than 100. If this limit is exceeded, excess elements will be discarded.
- The maximum number of parameters is 32. If this limit is exceeded, excess parameters will be discarded.

hiAppEvent.configure

configure(config: ConfigOption): void

Configures the application event logging function, such as setting the event logging switch and maximum size of the directory that stores the event logging files.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
config ConfigOption Yes Configuration items for application event logging.

Error codes

For details about the error codes, see Application Event Logging Error Codes.

ID Error Message
11103001 Invalid max storage quota value.

Example

// Disable the event logging function.
let config1: hiAppEvent.ConfigOption = {
  disable: true,
};
hiAppEvent.configure(config1);

// Set the maximum size of the file storage directory to 100 MB.
let config2: hiAppEvent.ConfigOption = {
  maxStorage: '100M',
};
hiAppEvent.configure(config2);

ConfigOption

Provides configuration options for application event logging.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
disable boolean No Whether to enable the event logging function. The default value is false. The value true means to disable the event logging function, and the value false means the opposite.
maxStorage string No Quota for the directory that stores event logging files. The default value is 10M.
If the directory size exceeds the specified quota when application event logging is performed, event logging files in the directory will be cleared one by one based on the generation time to ensure that directory size does not exceed the quota.
The quota value must meet the following requirements:
- The quota value consists of only digits and a unit (which can be one of [b|k|kb|m|mb|g|gb|t|tb], which are case insensitive.)
- The quota value must start with a digit. You can determine whether to pass the unit. If the unit is left empty, b (that is, byte) is used by default.

hiAppEvent.setUserId11+

setUserId(name: string, value: string): void

Sets a user ID.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
name string Yes Key of a user ID. The value is string that contains a maximum of 256 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must not start with a digit.
value string Yes Value of a user ID. It can contain a maximum of 256 characters. If the value is null or left empty, the user ID is cleared.

Error codes

ID Error Message
401 Parameter error.

Example

import hilog from '@ohos.hilog';

try {
  hiAppEvent.setUserId('key', 'value');
} catch (error) {
  hilog.error(0x0000, 'hiAppEvent', `failed to setUserId event, code=${error.code}`);
}

hiAppEvent.getUserId11+

getUserId(name: string): string

Obtains the value set by setUserId.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
name string Yes Key of a user ID. The value is string that contains a maximum of 256 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must not start with a digit.

Return value

Type Description
string Value of a user ID. If no user ID is found, an empty string is returned.

Error codes

ID Error Message
401 Parameter error.

Example

import hilog from '@ohos.hilog';

hiAppEvent.setUserId('key', 'value');
try {
  let value: string = hiAppEvent.getUserId('key');
  hilog.info(0x0000, 'hiAppEvent', `getUserId event was successful, userId=${value}`);
} catch (error) {
  hilog.error(0x0000, 'hiAppEvent', `failed to getUserId event, code=${error.code}`);
}

hiAppEvent.setUserProperty11+

setUserProperty(name: string, value: string): void

Sets user properties.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
name string Yes Key of a user property. The value is string that contains a maximum of 256 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must not start with a digit.
value string Yes Value of a user property. It is a string that contains a maximum of 1024 characters. If the value is null, undefine, or empty, the user property is cleared.

Error codes

ID Error Message
401 Parameter error.

Example

import hilog from '@ohos.hilog';

try {
  hiAppEvent.setUserProperty('key', 'value');
} catch (error) {
  hilog.error(0x0000, 'hiAppEvent', `failed to setUserProperty event, code=${error.code}`);
}

hiAppEvent.getUserProperty11+

getUserProperty(name: string): string

Obtains the value set by setUserProperty.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
name string Yes Key of a user property. The value is string that contains a maximum of 256 characters, including digits (0 to 9), letters (a to z), underscore (_), and dollar sign ($). It must not start with a digit.

Return value

Type Description
string Value of a user property. If no user ID is found, an empty string is returned.

Error codes

ID Error Message
401 Parameter error.

Example

import hilog from '@ohos.hilog';

hiAppEvent.setUserProperty('key', 'value');
try {
  let value: string = hiAppEvent.getUserProperty('key');
  hilog.info(0x0000, 'hiAppEvent', `getUserProperty event was successful, userProperty=${value}`);
} catch (error) {
  hilog.error(0x0000, 'hiAppEvent', `failed to getUserProperty event, code=${error.code}`);
}

hiAppEvent.addWatcher

addWatcher(watcher: Watcher): AppEventPackageHolder

Adds a watcher to subscribe to application events.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
watcher Watcher Yes Watcher for application events.

Return value

Type Description
AppEventPackageHolder Subscription data holder. If the subscription fails, null will be returned.

Error codes

For details about the error codes, see Application Event Logging Error Codes.

ID Error Message
11102001 Invalid watcher name.
11102002 Invalid filtering event domain.
11102003 Invalid row value.
11102004 Invalid size value.
11102005 Invalid timeout value.

Example

import hilog from '@ohos.hilog';

// 1. If callback parameters are passed to the watcher, you can have subscription events processed in the callback that is automatically triggered.
hiAppEvent.addWatcher({
  name: "watcher1",
  appEventFilters: [
    {
      domain: "test_domain",
      eventTypes: [hiAppEvent.EventType.FAULT, hiAppEvent.EventType.BEHAVIOR]
    }
  ],
  triggerCondition: {
    row: 10,
    size: 1000,
    timeOut: 1
  },
  onTrigger: (curRow: number, curSize: number, holder: hiAppEvent.AppEventPackageHolder) => {
    if (holder == null) {
      hilog.error(0x0000, 'hiAppEvent', "holder is null");
      return;
    }
    hilog.info(0x0000, 'hiAppEvent', `curRow=${curRow}, curSize=${curSize}`);
    let eventPkg: hiAppEvent.AppEventPackage | null = null;
    while ((eventPkg = holder.takeNext()) != null) {
      hilog.info(0x0000, 'hiAppEvent', `eventPkg.packageId=${eventPkg.packageId}`);
      hilog.info(0x0000, 'hiAppEvent', `eventPkg.row=${eventPkg.row}`);
      hilog.info(0x0000, 'hiAppEvent', `eventPkg.size=${eventPkg.size}`);
      for (const eventInfo of eventPkg.data) {
        hilog.info(0x0000, 'hiAppEvent', `eventPkg.data=${eventInfo}`);
      }
    }
  }
});

// 2. If no callback parameters are passed to the watcher, you can have subscription events processed manually through the subscription data holder.
let holder = hiAppEvent.addWatcher({
  name: "watcher2",
});
if (holder != null) {
  let eventPkg: hiAppEvent.AppEventPackage | null = null;
  while ((eventPkg = holder.takeNext()) != null) {
    hilog.info(0x0000, 'hiAppEvent', `eventPkg.packageId=${eventPkg.packageId}`);
    hilog.info(0x0000, 'hiAppEvent', `eventPkg.row=${eventPkg.row}`);
    hilog.info(0x0000, 'hiAppEvent', `eventPkg.size=${eventPkg.size}`);
    for (const eventInfo of eventPkg.data) {
      hilog.info(0x0000, 'hiAppEvent', `eventPkg.data=${eventInfo}`);
    }
  }
}

// 3. You can have the watcher processed the subscription event in the onReceive function.
hiAppEvent.addWatcher({
  name: "watcher3",
  appEventFilters: [
    {
      domain: "test_domain",
      eventTypes: [hiAppEvent.EventType.FAULT, hiAppEvent.EventType.BEHAVIOR]
    }
  ],
  onReceive: (domain: string, appEventGroups: Array<hiAppEvent.AppEventGroup>) => {
    hilog.info(0x0000, 'hiAppEvent', `domain=${domain}`);
    for (const eventGroup of appEventGroups) {
      hilog.info(0x0000, 'hiAppEvent', `eventName=${eventGroup.name}`);
      for (const eventInfo of eventGroup.appEventInfos) {
        hilog.info(0x0000, 'hiAppEvent', `event=${JSON.stringify(eventInfo)}`, );
      }
    }
  }
});

hiAppEvent.removeWatcher

removeWatcher(watcher: Watcher): void

Removes a watcher to unsubscribe from application events.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
watcher Watcher Yes Watcher for application events.

Error codes

For details about the error codes, see Application Event Logging Error Codes.

ID Error Message
11102001 Invalid watcher name.

Example

// 1. Define a watcher for application events.
let watcher: hiAppEvent.Watcher = {
  name: "watcher1",
}

// 2. Add the watcher to subscribe to application events.
hiAppEvent.addWatcher(watcher);

// 3. Remove the watcher to unsubscribe from application events.
hiAppEvent.removeWatcher(watcher);

Watcher

Defines parameters for a Watcher object.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
name string Yes Unique name of a watcher.
triggerCondition TriggerCondition No Subscription callback triggering condition. This parameter takes effect only when it is passed together with onTrigger.
appEventFilters AppEventFilter[] No Subscription filtering condition. This parameter is passed only when subscription events need to be filtered.
onTrigger (curRow: number, curSize: number, holder: AppEventPackageHolder) => void No Subscription callback. This parameter takes effect only when it is passed together with triggerCondition. The input arguments are described as follows:
curRow: total number of subscription events when the callback is triggered.
curSize: total size of subscribed events when the callback is triggered, in bytes.
holder: subscription data holder, which can be used to process subscribed events.
onReceive11+ (domain: string, appEventGroups: Array<AppEventGroup>) => void No Real-time subscription callback. Only this callback function is triggered if it is passed together with onTrigger. The input arguments are described as follows:
domain: domain name.
appEventGroups: event group.

TriggerCondition

Defines callback triggering conditions. A callback is triggered when any specified condition is met.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
row number No Number of events.
size number No Event data size, in bytes.
timeOut number No Timeout interval, in unit of 30s.

AppEventFilter

Defines parameters for an AppEventFilter object.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
domain string Yes Event domain.
eventTypes EventType[] No Event types.
names11+ string[] No Names of the events to be subscribed.

AppEventPackageHolder

Defines a subscription data holder for processing subscription events.

constructor

constructor(watcherName: string)

A constructor used to create a holder object for subscription data. It is associated with a Watcher object based on its name.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
watcherName string Yes Watcher name.

Example

let holder1: hiAppEvent.AppEventPackageHolder = new hiAppEvent.AppEventPackageHolder("watcher1");

setSize

setSize(size: number): void

Sets the threshold for the data size of the application event package obtained each time.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Parameters

Name Type Mandatory Description
size number Yes Data size threshold, in bytes. The default value is 512*1024.

Error codes

For details about the error codes, see Application Event Logging Error Codes.

ID Error Message
11104001 Invalid size value.

Example

let holder2: hiAppEvent.AppEventPackageHolder = new hiAppEvent.AppEventPackageHolder("watcher2");
holder2.setSize(1000);

takeNext

takeNext(): AppEventPackage

Extracts subscription event data based on the configured data size threshold. If all subscription event data has been extracted, null will be returned.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Return value

Type Description
AppEventPackage Event package object. If all subscription event data has been retrieved, null is returned.

Example

let holder3: hiAppEvent.AppEventPackageHolder = new hiAppEvent.AppEventPackageHolder("watcher3");
let eventPkg = holder3.takeNext();

AppEventPackage

Defines parameters for an AppEventPackage object.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
packageId number Yes Event package ID, which is named from 0 in ascending order.
row number Yes Number of events in the event package.
size number Yes Event size of the event package, in bytes.
data string[] Yes Event data in the event package.

AppEventGroup11+

Defines the event group returned by a subscription.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Mandatory Description
name string Yes Event name.
appEventInfos Array<AppEventInfo> Yes Event object group.

hiAppEvent.clearData

clearData(): void

Clears local application event logging data.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Example

hiAppEvent.clearData();

EventType

Enumerates event types.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Value Description
FAULT 1 Fault event.
STATISTIC 2 Statistical event.
SECURITY 3 Security event.
BEHAVIOR 4 Behavior event.

domain11+

Defines the domain name of predefined events.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Description
OS string System domain.

event

Defines the names of predefined events.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Description
USER_LOGIN string User login event.
USER_LOGOUT string User logout event.
DISTRIBUTED_SERVICE_START string Distributed service startup event.
APP_CRASH11+ string Application crash event.
APP_FREEZE11+ string Application freeze event.

param

Defines the names of predefined event parameters.

System capability: SystemCapability.HiviewDFX.HiAppEvent

Name Type Description
USER_ID string Custom user ID.
DISTRIBUTED_SERVICE_NAME string Distributed service name.
DISTRIBUTED_SERVICE_INSTANCE_ID string Distributed service instance ID.