Internal HTTP Client


This stage supports HTTP requests through GET, POST, or PUT, and supports caching (generating keys with URL and request parameters) for further queries.

Configuration

The configuration tabs for this stage are General, Basic, Input/Output, Request, and QueryConfig.

General

Name

Required?

Description

Name

Yes

The name of the stage.

Description

No

The description of the stage.

Stage Library

Yes

The streaming operator library to which the stage belongs.

Required Fields

No

The fields that the data records must contain. If the specified fields are not included, the record will be filtered out.

Preconditions

No

The conditions that must be satisfied by the data records. Records that do not meet the conditions will be filtered out. For example, ${record:value('/value') > 0}. For the syntax of EL expressions, see Expression Language.

On Record Error

Yes

The processing method for error data.

  • Discard: Error data will be discarded and ignored

  • Send to Error: Error messages will be reported

  • Stop Pipeline: The pipeline will be stopped

Basic

Name

Required?

Description

Enable Cache Fields

No

Specify whether to enable caching. Local cache enables fast data processing. When the pipeline is paused, restarted, or retried, the cached data will be lost.

ExpireRule

No

Select the expiring time of the cache.

Quality Filter

No

Filter the data according to the data quality. Only records that meet the quality conditions will be processed by this stage.

Input/Output

Name

Required?

Description

Input Point

Yes

Specify the input point of the records, using the format {modelId}::{pointId}.

Output Point

No

Specify the output point of the records, using the format {modelId}::{pointId}.

Request

Name

Required?

Description

Request Method

Yes

Select the API request method. + Get + Post + Put

Request URL

Yes

Specify the API request URL.

Param Generate: Position

Yes

Specify the position of the parameters and values that are required by the API request. + URL Path + URL Query + Request Body + Header

Param Generate: Param Key

Yes

Specify the parameter name.

Param Generate: URLParam Type

Yes

Select the parameter type. + ByField + ByInput

Param Generate: Param Value

Yes

Specify or select the value of the parameter.

Access Key

Yes

Enter the access key of the application, which is used for API request authentication (the access key can be generated by registering the application on EnOS Management Console).

Secret Key

Yes

Enter the secret key of the application.

QueryConfig

Name

Required?

Description

Parallel Number

Yes

Select the method of parallel requests. Based on the limit of API service, options are System Default and User Defined.

  • System Default: The default number of parallel requests that are supported by the system.

  • User Defined: Customized number of parallel requests. Enter a specific number in the UserDefined field (If the provided number exceeds the limit of the stage configuration, an error will be reported when starting the pipeline).

Enable Retry

No

Specify whether to retry upon request failure, and enter a specific number of retry attempts in the Retry Attempts field.

Output Results

The output results of this stage are included in the lookupTag field of the attr struct. The description of the fields are as follows:

Name

Data Type

Description

hasData

Boolean

Indicates whether the API request is successful.

response

Object

If the request is successful, displays the response data. The returnBy field indicates if the response is returned by Redis or HTTP.

cacheKey

String

The request URL composed of Request URL + Param Generate configuration.

Output Example

../../../_images/http_lookup_result.png