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kafka-logger.md

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kafka-logger

Description

kafka-logger is a plugin which works as a Kafka client driver for the ngx_lua nginx module.

This plugin provides the ability to push requests log data as JSON objects to your external Kafka clusters. In case if you did not receive the log data don't worry give it some time it will automatically send the logs after the timer function expires in our Batch Processor.

For more info on Batch-Processor in Apache APISIX please refer. Batch-Processor

Attributes

Name Type Requirement Default Valid Description
broker_list object required An array of Kafka brokers.
kafka_topic string required Target topic to push data.
producer_type string optional async ["async", "sync"] Producer's mode of sending messages.
required_acks integer optional 1 [0, 1, -1] The number of acknowledgments the producer requires the leader to have received before considering a request complete. This controls the durability of records that are sent. Semantics is the same as kafka producer acks(If set acks=0 then the producer will not wait for any acknowledgment from the server at all. The record will be immediately added to the socket buffer and considered sent. acks=1 This will mean the leader will write the record to its local log but will respond without awaiting full acknowledgement from all followers. acks=-1 This means the leader will wait for the full set of in-sync replicas to acknowledge the record.).
key string optional Used for partition allocation of messages.
timeout integer optional 3 [1,...] Timeout for the upstream to send data.
name string optional "kafka logger" A unique identifier to identity the batch processor.
meta_format enum optional "default" ["default"，"origin"] default: collect the request information with default JSON way. origin: collect the request information with original HTTP request. example
include_req_body boolean optional false [false, true] Whether to include the request body. false: indicates that the requested body is not included; true: indicates that the requested body is included. Note: if the request body is too big to be kept in the memory, it can't be logged due to Nginx's limitation.
include_req_body_expr array optional When include_req_body is true, control the behavior based on the result of the lua-resty-expr expression. If present, only log the request body when the result is true.
include_resp_body boolean optional false [false, true] Whether to include the response body. The response body is included if and only if it is true.
include_resp_body_expr array optional When include_resp_body is true, control the behavior based on the result of the lua-resty-expr expression. If present, only log the response body when the result is true.
cluster_name integer optional 1 [0,...] the name of the cluster. When there are two or more kafka clusters, you can specify different names. And this only works with async producer_type.

The plugin supports the use of batch processors to aggregate and process entries(logs/data) in a batch. This avoids frequent data submissions by the plugin, which by default the batch processor submits data every 5 seconds or when the data in the queue reaches 1000. For information or custom batch processor parameter settings, see Batch-Processor configuration section.

examples of meta_format

  • default:

    {
 "upstream": "127.0.0.1:1980",
 "start_time": 1619414294760,
 "client_ip": "127.0.0.1",
 "service_id": "",
 "route_id": "1",
 "request": {
   "querystring": {
     "ab": "cd"
   },
   "size": 90,
   "uri": "/hello?ab=cd",
   "url": "http://localhost:1984/hello?ab=cd",
   "headers": {
     "host": "localhost",
     "content-length": "6",
     "connection": "close"
   },
   "body": "abcdef",
   "method": "GET"
 },
 "response": {
   "headers": {
     "connection": "close",
     "content-type": "text/plain; charset=utf-8",
     "date": "Mon, 26 Apr 2021 05:18:14 GMT",
     "server": "APISIX/2.5",
     "transfer-encoding": "chunked"
   },
   "size": 190,
   "status": 200
 },
 "server": {
   "hostname": "localhost",
   "version": "2.5"
 },
 "latency": 0
}

  • origin:

    GET /hello?ab=cd HTTP/1.1
host: localhost
content-length: 6
connection: close

abcdef

Info

The message will write to the buffer first. It will send to the kafka server when the buffer exceed the batch_max_size, or every buffer_duration flush the buffer.

In case of success, returns true. In case of errors, returns nil with a string describing the error (buffer overflow).

Sample broker list

This plugin supports to push in to more than one broker at a time. Specify the brokers of the external kafka servers as below sample to take effect of this functionality.

{
    "127.0.0.1":9092,
    "127.0.0.1":9093
}

How To Enable

The following is an example on how to enable the kafka-logger for a specific route.

curl http://127.0.0.1:9080/apisix/admin/routes/5 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "plugins": {
       "kafka-logger": {
           "broker_list" :
             {
               "127.0.0.1":9092
             },
           "kafka_topic" : "test2",
           "key" : "key1",
           "batch_max_size": 1,
           "name": "kafka logger"
       }
    },
    "upstream": {
       "nodes": {
           "127.0.0.1:1980": 1
       },
       "type": "roundrobin"
    },
    "uri": "/hello"
}'

Test Plugin

success:

$ curl -i http://127.0.0.1:9080/hello
HTTP/1.1 200 OK
...
hello, world

Metadata

Name Type Requirement Default Valid Description
log_format object optional {"host": "$host", "@timestamp": "$time_iso8601", "client_ip": "$remote_addr"} Log format declared as key value pair in JSON format. Only string is supported in the value part. If the value starts with $, it means to get APISIX variable or Nginx variable.

Note that the metadata configuration is applied in global scope, which means it will take effect on all Route or Service which use kafka-logger plugin.

Example

curl http://127.0.0.1:9080/apisix/admin/plugin_metadata/kafka-logger -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "log_format": {
        "host": "$host",
        "@timestamp": "$time_iso8601",
        "client_ip": "$remote_addr"
    }
}'

It is expected to see some logs like that:

{"host":"localhost","@timestamp":"2020-09-23T19:05:05-04:00","client_ip":"127.0.0.1","route_id":"1"}
{"host":"localhost","@timestamp":"2020-09-23T19:05:05-04:00","client_ip":"127.0.0.1","route_id":"1"}

Disable Plugin

Remove the corresponding json configuration in the plugin configuration to disable the kafka-logger. APISIX plugins are hot-reloaded, therefore no need to restart APISIX.

$ curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "methods": ["GET"],
    "uri": "/hello",
    "plugins": {},
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'