Cloud API Management Circuit Breaker Service Policy Configuration Values
Configuration Values
The following configuration values can be defined while configuring the Circuit Breaker Service policy on the Call Transformation page:
Currently, the obs-window(observation window) is based on call count, so this value represents the number of calls used to calculate whether the circuit should trip. In future releases, duration-based obs-window will also be supported, where this value would be treated as duration in minutes.
| Field name | Type | Field Value | Required/Optional | Description |
|---|---|---|---|---|
| Processing Adapter | String | CAM_Circuit_Breaker_Service | Required | Policy to trip the circuit open on receiving failed responses from the backend server. |
| Perform Pre-processing | Boolean | Enabled / Disabled | Required | 1. When enabled, Perform-post processing must also be enabled. 2. When enabled, the circuit breaker compares the configured API response time with the actual response time before forwarding the request to the backend. |
| Data to make available for pre-processing (PreInput Value) | Map | |||
| Float (Greater than 0, less than 100) | obs-error-percentage | Required | The threshold error percentage after which the circuit will trip for the given observation window (obs-window). | |
| Integer (Greater than 0) | obs-open-duration | Required | Duration to wait in the open state. In minutes. | |
| Integer (Greater than 0) | obs-window | Required | The number of calls used to calculate whether the circuit should trip. Currently based on call count; duration-based windows planned for future releases. | |
| Float (Greater than 0, less than 100) | obs-slow-call-rate | Optional | The threshold slow call percentage after which the circuit will trip for the given observation window. | |
| Integer (Greater than 0) | obs-slow-call-duration | Optional | The threshold for slow call duration in milliseconds. Any call duration above this duration will be recorded as a slow call. | |
| Integer (Greater than 0) | permit-half-open | Required | Number of calls to be permitted in the half-open state. The decision of whether the circuit moves to the closed state is based on whether more error percentage calls succeed in the half-open state than the permitted number of calls. | |
| Integer (Greater than 0) | min-calls | Required | The minimum number of calls to be considered when calculating the error percentage. | |
| Integer (Default: 1000 ms / 1 second) | cleanup-delay | Optional | This timeout period is the duration to wait after connect + read timeout to clean up the post-process that was not running. It specifically applies to situations where a Gateway Timeout stops the post-process from running. When this happens, an error is triggered on the circuit breaker object, which then updates the error count within the observation window. | |
| Perform Post-processing | Boolean | Enabled / Disabled | - | This field is required to be enabled if the Perform pre-processing field is enabled. |
| Data to make available for post-processing (PostInput Value) | Map | |||
| Integer (500, 400, 401, 402, 403) | http-status-list | Required | All status codes (500, 400, 401, 402, 403) increment the error call count by 1. |
Configuration Steps
Refer to the following for configuration steps:
- Configuring Call Transformations in Policy UI (Recommended — supports policy picker with inline help and auto-population)
- Configuring Call Transformation in Legacy UI
Tuning Profiles and Examples
For practical examples on how to configure these parameters based on your use case and traffic patterns, refer to the Circuit Breaker Usage page, which includes:
- Strict Profile (Fast Decision APIs)
- Defensive Profile (High Reliability / Default)
- Initialization Profile (Heavy/Legacy Backends)
- High-Volume Traffic Profiles
- Advanced Formulas for High Volume
