Events can be notified or published to external systems from WSO2 servers using event publishers. Event publishers enable you to manage event publishing and notifications. They allow publishing events via multiple transports in JSON, XML, Map, text, and WSO2Event formats to various endpoints and data stores.
Configuring global properties
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| When the output event adapter type is RDBMS, it is allowed to change the queries used to perform the standard database operations. This enables you to use RDBMS database types that use different queries. Customised values can be defined for the following used in standard queries. | Attribute/activity | Current query |
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| string | VARCHAR(255) | double | DOUBLE | integer | INT | long | BIGINT | float | FLOAT | createTable | CREATE TABLE $TABLE_NAME ($COLUMN_TYPES) | insertDataToTable | INSERT INTO $TABLE_NAME ($COLUMNS) VALUES ($VALUES) | isTableExist | SELECT * FROM $TABLE_NAME limit 1 | updateTableRow | UPDATE $TABLE_NAME SET $COLUMN_VALUES WHERE $CONDITION | comma | , | questionMark | ? | equal | = | and | AND | selectAllColumnsDataTypeInTable | SELECT COLUMN_NAME, DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '$TABLE_NAME' | | selectFromTable | SELECT $COLUMNS FROM $TABLE_NAME | oracle.string | varchar2(255) | oracle.long | CLOB | oracle.double | BINARY_DOUBLE | oracle.isTableExist | SELECT * FROM $TABLE_NAME WHERE ROWNUM = 1 | oracle.selectAllColumnsDataTypeInTable | SELECT COLUMN_NAME, DATA_TYPE FROM USER_TAB_COLS WHERE TABLE_NAME = '$TABLE_NAME' | mssql.string | varchar2(255) | mssql.isTableExist | SELECT TOP 1 * FROM $TABLE_NAME | mssql.selectAllColumnsDataTypeInTable | SELECT COLUMN_NAME, DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '$TABLE_NAME' | h2.integer | varchar2(255) | h2.long | REAL | h2.selectAllColumnsDataTypeInTable | SHOW COLUMNS FROM $TABLE_NAME |
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| The following properties are available for the http output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The size of the queue that is used to hold events before they are forwarded to the event stream. | Integer | 10000 | defaultMaxConnectionsPerHost | The maximum number of connections allowed per host configuration. | Integer | 50 | maxTotalConnections | The maximum number of connections allowed overall. | Integer | 1000 |
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| The following properties are available for the jms output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 |
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| The following properties are available for the mqtt output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 | connectionKeepAliveInterval | The time interval in milliseconds at which a check should be carried out to identify inactive threads. | Integer | 60 |
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| The following properties are available for the kafka output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 |
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| The following properties are available for the email output event adapter type. | Property Key | Description | Data Type | Default Value |
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mail.smtp.from | The email address used by the publisher to publish events. | String | abcd@gmail.com | mail.smtp.user | The username used by the publisher to publish events via email. | String | abcd | mail.smtp.password | The password used by the publish events via email. | String | xxxx | mail.smtp.host | The host of the email server. | String | smtp.gmail.com | mail.smtp.port | The port of the email server. | Integer | 587 | mail.smtp.starttls.enable | This property specifies whether STARTTLS encryption is enabled or not. STARTTLS is an extension which enables a plain text connection to be upgraded to an encrypted (SSL or TLS) connection. | Boolean | true | mail.smtp.auth | This property specifies whether SMTP authentication is enabled or not. | Boolean | true | minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 |
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| The following properties are available for the UI output event adapter type. | Property Key | Description | Data Type | Default Value |
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eventQueueSize | The maximum number of events allowed in the adapter queue when the rate at which a UI publisher receives events to be published higher than the rate at which the relevant UI is accepting the events. When the number of events received by the publisher exceeds the value specified for this property, the publisher stops accepting events until the events that are already in the queue get published. Therefore, if you want to reduce system latency, a higher queue size should be specified. | Integer | 30 | minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 |
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| The following properties are available for the websocket-local output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 |
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| The following properties are available for the websocket output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 |
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| The following properties are available for the soap output event adapter type. | Property Key | Description | Data Type | Default Value |
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minThread | The minimum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 8 | maxThread | The maximum number of threads (including idle threads) that should be available in the thread pool at a given time. | Integer | 100 | keepAliveTimeInMillis | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 20000 | jobQueueSize | The maximum number of milliseconds that idle threads should be kept alive when the total number of threads in the pool exceeds the number of cores in the machine. | Integer | 10000 | axis2ClientConnectionTimeout | The number of milliseconds allowed to elapse before the Axis2 client connection times out. | Integer | 10000 | reuseHTTPClient | If this property is set to true, it is allowed to reuse the connection to the HTTP client for subsequent requests. | Boolean | true | autoReleaseConnection | If this property is set to true, inactive connections are automatically killed. | Boolean | true | maxConnectionsPerHost | The maximum number of connections allowed per host configuration. | Integer | 50 |
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Event publisher configuration
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| Create Event Publisher |
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| Create Event Publisher |
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The above sections of an event publisher configuration are described below.
| Section | Description |
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| From | The event stream from which the event publisher will fetch the events for publishing. |
| To | An output event adapter(transport) configuration that is used to send the events to. |
| Adapter properties | Output event adapters contain three types of adapter properties in their configuration as explained below. - Static Adapter Properties : You can add these properties via the management console. You cannot change them based on the event.
- Dynamic Adapter Properties : You can add these properties via the management console. You can change them for each event by adding event attributes as follows: {{ attribute }} E.g. http://localhost:8000/endpoint/{{endpointId}}
- Global Adapter Properties : These properties come from the
<PRODUCT_HOME>/repository/conf/output-event-adapters.xml file. They are common for all adapters on its kind which was defined during the event publisher creation.
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| Mapping configuration | The format of the message that needs to be sent. You can configure custom mappings on the selected format via advanced settings. |
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| Creating event publishers |
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| Creating event publishers |
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Creating event publishers
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Create an XML file with the following event publisher configurations. An event publisher implementation should start with <eventPublisher> as the root element.
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In the following configuration, specify the respective adapter properties based on the transport type of the publisher within the <from> element. For the respective adapter properties of the event publisher configuration based on the transport type, see Publishing Events via Various Transports. |
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<eventPublisher name="EVENT-PUBLISHER-NAME" statistics="disable"
trace="disable" xmlns="http://wso2.org/carbon/eventpublisher">
<from streamName="Test Stream" version="1.0.0"/>
<mapping customMapping="disable" type="text"/>
<to eventAdapterType="EVENT-ADAPTER-TYPE">
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</to>
</eventPublisher> |
The properties of the above configuration are described below.
| Adapter property | Description |
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name | Name of the event publisher |
statistics | Whether monitoring event statistics is enabled for the publisher |
trace | Whether tracing events is enabled for the publisher |
xmlns | XML namespace for event receivers |
streamName | Name of the event stream from which the publisher publishes events. |
version | Version of the event stream from which the publisher publishes events. |
customMapping | Whether a custom mapping is enabled on the receiver. |
type | Type of the enabled custom mapping. |
eventAdapterType | Type of the event adapter. |
Add the XML file to the <DAS_HOME>/repository/deployment/server/eventpublishers directory. Since hot deployment is supported in the product, you can simply add/remove event publisher configuration files to deploy/undeploy event publishers to/from the server.
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First define the stream to which the publisher is publishing data from to activate the publisher. When receiving WSO2Events, the outgoing stream definition that you select in the advanced input mappings must also be defined, to activate the event publisher. When you click Inactive Event Publishers in the Available Event Publishers screen, if an event publisher is in the inactive state due to some issue in the configurations, you view a short message specifying the reason why the event publisher is inactive as shown below. A similar message is also printed on the CLI. |
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