proxy-mirror

Description

The proxy-mirror Plugin can be used to mirror client requests. Traffic mirroring duplicates the real online traffic to the mirroring service. This enables specific analysis of the online traffic or request content without interrupting the online service.

note

The response returned by the mirror request is ignored.

Attributes

Name	Type	Required	Default	Valid values	Description
host	string	True			Address of the mirror service. It needs to contain the scheme (`http(s)` or `grpc(s)`) but without the path. For example, `http://127.0.0.1:9797`.
path	string	False			Path of the mirror request. If unspecified, current path will be used. If it is for mirroring grpc traffic, this option is no longer applicable.
path_concat_mode	string	False	replace	[“replace”, “prefix”]	If the path of a mirror request is specified, set the concatenation mode of request paths. The `replace` mode will directly use `path` as the path of the mirror request. The `prefix` mode will use the `path` + `source request URI` as the path to the mirror request. If it is for mirroring grpc traffic, this option is no longer applicable too.
sample_ratio	number	False	1	[0.00001, 1]	Ratio of the requests that will be mirrored.

You can customize the proxy timeouts for the mirrored sub-requests by configuring the plugin_attr key in your configuration file (conf/config.yaml). This can be used for mirroring traffic to a slow backend.

conf/config.yaml

plugin_attr:
  proxy-mirror:
    timeout:
      connect: 2000ms
      read: 2000ms
      send: 2000ms

Name	Type	Default	Description
connect	string	60s	Connect timeout to the mirrored Upstream.
read	string	60s	Read timeout to the mirrored Upstream.
send	string	60s	Send timeout to the mirrored Upstream.

Enable Plugin

You can enable the Plugin on a specific Route as shown below:

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": {
        "proxy-mirror": {
           "host": "http://127.0.0.1:9797"
        }
    },
    "upstream": {
        "nodes": {
            "127.0.0.1:1999": 1
        },
        "type": "roundrobin"
    },
    "uri": "/hello"
}'

Specify the timeout for mirror subrequests

We can specify the timeout for subrequests in plugin_attr in conf/config.yaml. This is useful in connection reuse scenarios when mirroring traffic to a very slow backend service.

Since mirror requests are implemented as sub-requests, delays in sub-requests will block the original request until the sub-requests are completed. So you can configure the timeout time to protect the sub-requests from excessive delays that affect the original requests.

Name	Type	Default	Description
connect	string	60s	Connection timeout for mirror request to upstream.
read	string	60s	The time that APISIX maintains the connection with the mirror server; if APISIX does not receive a response from the mirror server within this time, the connection is closed.
send	string	60s	The time that APISIX maintains the connection with the mirror server; if APISIX does not send a request within this time, the connection is closed.

plugin_attr:
  proxy-mirror:
    timeout:
      connect: 2000ms
      read: 2000ms
      send: 2000ms

Example usage

tip

For testing you can create a test server by running:

python -m http.server 9797

Once you have configured the Plugin as shown above, the requests made will be mirrored to the configured host.

curl http://127.0.0.1:9080/hello -i

HTTP/1.1 200 OK
...
hello world

Delete Plugin

To remove the proxy-mirror 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",
    "plugins": {},
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1999": 1
        }
    }
}'