#Usecase
- Throttle limits are configured in the APIX-G configuration
- By default APIX-G returns "HTTP-429 Too Many Requests" response when the throttle limit is hit.

#Requirement
The request is to have APIX-G return the "Retry-After" header as well in the error response.

This article provides samples for the above usecase with TIBCO API Exchange Gateway(APIX-G)

All Supported Platforms

For this a transformation set in FaultReportXSLT field on the Facade Operation can be used.

Please refer to attached archive:
- "mera240" is the sample config
- "fault_set_status-code_TextPayload.xsl" is the xsl where the custom header and response are returned by APIX-G in case of rate limit error
- sample logs with and withou the stylesheet are also attached.

Please note that this is just sample provided as-is and should be tested thoroughly and modified yourself as required.

#Notes
- Please note that this stylesheet can work-off of asg-error-code/message only.
- The actual throttle counter, limits etc are not available in the context for use in transformations
- However such entries are available in the engine log file though:
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2021 Jul 13 16:24:56:121 GMT -4 13JulCore Info [HTTP-NIO-Worker-1-2] - [user] [core-class] DEBUG: Applying throttle RT_3perMin
2021 Jul 13 16:24:56:121 GMT -4 13JulCore Info [HTTP-NIO-Worker-1-2] - [user] [core-class] INFO: Current count for rate throttle RT_3perMin increased to 2 max count 3
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2021 Jul 13 16:24:58:257 GMT -4 13JulCore Info [HTTP-NIO-Worker-1-4] - [user] [core-class] ERROR: Throttle limit reached for rate throttle RT_3perMinthrottle key  Current count: 4
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