Version: Next

api-breaker

Description#

The api-breaker Plugin implements circuit breaker functionality to protect Upstream services.

note

Whenever the Upstream service responds with a status code from the configured unhealthy.http_statuses list for the configured unhealthy.failures number of times, the Upstream service will be considered unhealthy.

The request is then retried in 2, 4, 8, 16 ... seconds until the max_breaker_sec.

In an unhealthy state, if the Upstream service responds with a status code from the configured list healthy.http_statuses for healthy.successes times, the service is considered healthy again.

Attributes#

Name	Type	Required	Default	Valid values	Description
break_response_code	integer	True		[200, ..., 599]	HTTP error code to return when Upstream is unhealthy.
break_response_body	string	False			Body of the response message to return when Upstream is unhealthy.
break_response_headers	array[object]	False		[{"key":"header_name","value":"can contain Nginx $var"}]	Headers of the response message to return when Upstream is unhealthy. Can only be configured when the `break_response_body` attribute is configured. The values can contain APISIX variables. For example, we can use `{"key":"X-Client-Addr","value":"$remote_addr:$remote_port"}`.
max_breaker_sec	integer	False	300	>=3	Maximum time in seconds for circuit breaking.
unhealthy.http_statuses	array[integer]	False	[500]	[500, ..., 599]	Status codes of Upstream to be considered unhealthy.
unhealthy.failures	integer	False	3	>=1	Number of failures within a certain period of time for the Upstream service to be considered unhealthy.
healthy.http_statuses	array[integer]	False	[200]	[200, ..., 499]	Status codes of Upstream to be considered healthy.
healthy.successes	integer	False	3	>=1	Number of consecutive healthy requests for the Upstream service to be considered healthy.

Enable Plugin#

The example below shows how you can configure the Plugin on a specific Route:

note

You can fetch the admin_key from config.yaml and save to an environment variable with the following command:

admin_key=$(yq '.deployment.admin.admin_key[0].key' conf/config.yaml | sed 's/"//g')

curl "http://127.0.0.1:9180/apisix/admin/routes/1" \
-H "X-API-KEY: $admin_key" -X PUT -d '
{
    "plugins": {
        "api-breaker": {
            "break_response_code": 502,
            "unhealthy": {
                "http_statuses": [500, 503],
                "failures": 3
            },
            "healthy": {
                "http_statuses": [200],
                "successes": 1
            }
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    },
    "uri": "/hello"
}'

In this configuration, a response code of 500 or 503 three times within a certain period of time triggers the unhealthy status of the Upstream service. A response code of 200 restores its healthy status.

Example usage#

Once you have configured the Plugin as shown above, you can test it out by sending a request.

curl -i -X POST "http://127.0.0.1:9080/hello"

If the Upstream service responds with an unhealthy response code, you will receive the configured response code (break_response_code).

HTTP/1.1 502 Bad Gateway
...
<html>
<head><title>502 Bad Gateway</title></head>
<body>
<center><h1>502 Bad Gateway</h1></center>
<hr><center>openresty</center>
</body>
</html>

Delete Plugin#

To remove the api-breaker Plugin, you can delete the corresponding JSON configuration from the Plugin configuration. APISIX will automatically reload and you do not have to restart for this to take effect.

curl http://127.0.0.1:9180/apisix/admin/routes/1 \
-H "X-API-KEY: $admin_key" -X PUT -d '
{
    "uri": "/hello",
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'