RoundRobin with Failover
For a target operation group of RoundRobin with Failover type, the Core Engine selects the target operation as per the RoundRobin algorithm. See RoundRobin for details. After the target operation is selected, the Core Engine checks the health of the target operation using the HealthCheck reference functionality of TIBCO API Exchange Gateway. See HealthCheck for Reference.
The Core Engine processes the client request as follows:
- The Core Engine selects the target operation in a RoundRobin fashion.
- If the selected target operation within the target operation group is running and available, the facade request is forwarded to this target operation for processing.
- If the target operation is not running or times out, an alternate target operation is selected from the group of target operations using the RoundRobin algorithm. This process continues until a target operation is found within the target operations group that is available to process the request. The facade request is routed to the available target operation for processing.
The following variables are used to group the status codes to separate them from the MinimumFailoverHTTPStatusCode. The MinimumFailoverHTTPStatusCode is the minimum HTTP status code above which a failover is triggered. The default value is 502.
- ASG/Routing/HTTPStatusCodeInclusionSet: The codes to be allowed for failover are included in this variable. known It is a comma-separated list of status codes. For example, tibco.clientVar.ASG/Routing/HTTPStatusCodeInclusionSet
- ASG/Routing/HTTPStatusCodeExclusionSet: The codes to be restricted from failover are included in this variable. It is a comma-separated list of status codes. For example, tibco.clientVar.ASG/Routing/HTTPStatusCodeExclusionSet.
The following scenarios are covered:
| MinimumFailoverHTTPStatusCode
Default value: 502 Property is either defined or empty |
ASG/Routing/HTTPStatusCodeInclusionSet
Default value: Empty Property is either defined or empty |
ASG/Routing/HTTPStatusCodeExclusionSet
Default value: Empty Property is either defined or empty |
Effect |
|---|---|---|---|
| Value not provided | Value provided
For example, HTTPStatusCodeInclusionSet = 408, 421 |
Value not provided | Failover for all status codes greater or equal to
MinimumFailoverHTTPStatusCode(502), OR status code present in the inclusion list but NOT present in the exclusion list.
502 - Failover (equal to default MinimumFailoverHTTPStatusCode) 408 - Failover (available in HTTPStatusCodeInclusionSet) 429 - No failover (less then MinimumFailoverHTTPStatusCode) |
| Value provided
For example, MinimumFailoverHTTPStatusCode = 510 |
Value not provided | Value not provided | Failover for all status codes greater or equal to the provided
MinimumFailoverHTTPStatusCode(510), OR status code present in inclusion list but NOT present in the exclusion list
510 - Failover (equal to provided MinimumFailoverHTTPStatusCode) 502 - No Failover (less than MinimumFailoverHTTPStatusCode) |
| Value provided
For example, MinimumFailoverHTTPStatusCode = 510 |
Value provided
For example, HTTPStatusCodeInclusionSet = 503, 504 |
Value provided
For example, MinimumFailoverHTTPStatusCode = 596 |
Failover for all status codes greater or equal to
MinimumFailoverHTTPStatusCode(510), OR status code present in inclusion list but NOT present in the exclusion list
510 - Failover (equal to provided MinimumFailoverHTTPStatusCode) 503 - Failover(available in HTTPStatusCodeInclusionSet) 596 - No failover (available in HTTPStatusCodeExclusionSet) |
| Value not provided | Value not provided | Value not provided |
Failover for all status codes greater or equal to MinimumFailoverHTTPStatusCode(502) 502 - Failover (equal to MinimumFailoverHTTPStatusCode) 408 -No Failover |
| Value not provided | Value provided
For example, HTTPStatusCodeInclusionSet = 408, 421 |
Value provided
For example, HTTPStatusCodeExclusionSet = 596 |
Failover for all status codes greater or equal to
MinimumFailoverHTTPStatusCode(502), or status code present in inclusion list but not present in the exclusion list
502 - Failover(equal to MinimumFailoverHTTPStatusCode) 408 - Failover(available in HTTPStatusCodeInclusionSet) 596 - No failover(available in HTTPStatusCodeExclusionSet) |
| Value provided
For example, HTTPStatusCodeInclusionSet = 408, 421 |
Value not provided | Value provided
For example, HTTPStatusCodeExclusionSet = 596 |
Failover for all status codes greater or equal to MinimumFailoverHTTPStatusCode(510), OR status code present in inclusion list but NOT present in the exclusion list
510 - Failover(equal to MinimumFailoverHTTPStatusCode) 502 - Don't failover(less than MinimumFailoverHTTPStatusCode) 596 - Don't failover (available in HTTPStatusCodeExclusionSet) |
| Value not provided | Value not provided | Value provided
For example, HTTPStatusCodeExclusionSet = 510 |
Failover for all status codes greater or equal to
MinimumFailoverHTTPStatusCode(502), but NOT present in the inclusion list
502 - Failover(equal to provided MinimumFailoverHTTPStatusCode) 510 - No failover (available in HTTPStatusCodeExclusionSet) |
| Value provided or not provided | Value provided
For example, HTTPStatusCodeInclusionSet = 510 |
Value provided
For example, HTTPStatusCodeExclusionSet = 510 |
IF Inclusion and exclusion both contain duplicate entries then IllegalArgumentExceptionto is thrown with an additional message Given Http Code can not be part of BOTH Inclusion and Exclusion set and Engine ignores all the values given in HTTPStatusCodeInclusionSet and HTTPStatusCodeExclusionSet. (both values to be considered as EMPTY set) |