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Batch Processor

The batch processor can be used to aggregate entries(logs/any data) and process them in a batch. When the batch_max_size is set to 1 the processor will execute each entry immediately. Setting the batch max size more than 1 will start aggregating the entries until it reaches the max size or the timeout expires.

Configurations#

The only mandatory parameter to create a batch processor is a function. The function will be executed when the batch reaches the max size or when the buffer duration exceeds.

NameTypeRequirementDefaultValidDescription
namestringoptionallogger's name["http logger",...]A unique identifier used to identify the batch processor, which defaults to the name of the logger plug-in that calls the batch processor, such as plug-in "http logger" 's name is "http logger.
batch_max_sizeintegeroptional1000[1,...]Sets the maximum number of logs sent in each batch. When the number of logs reaches the set maximum, all logs will be automatically pushed to the HTTP/HTTPS service.
inactive_timeoutintegeroptional5[1,...]The maximum time to refresh the buffer (in seconds). When the maximum refresh time is reached, all logs will be automatically pushed to the HTTP/HTTPS service regardless of whether the number of logs in the buffer reaches the maximum number set.
buffer_durationintegeroptional60[1,...]Maximum age in seconds of the oldest entry in a batch before the batch must be processed.
max_retry_countintegeroptional0[0,...]Maximum number of retries before removing the entry from the processing pipeline when an error occurs.
retry_delayintegeroptional1[0,...]Number of seconds the process execution should be delayed if the execution fails.

The following code shows an example of how to use batch processor in your plugin:

local bp_manager_mod = require("apisix.utils.batch-processor-manager")
...

local plugin_name = "xxx-logger"
local batch_processor_manager = bp_manager_mod.new(plugin_name)
local schema = {...}
local _M = {
...
name = plugin_name,
schema = batch_processor_manager:wrap_schema(schema),
}

...


function _M.log(conf, ctx)
local entry = {...} -- data to log

if batch_processor_manager:add_entry(conf, entry) then
return
end
-- create a new processor if not found

-- entries is an array table of entry, which can be processed in batch
local func = function(entries)
-- serialize to json array core.json.encode(entries)
-- process/send data
return true
-- return false, err_msg, first_fail if failed
-- first_fail(optional) indicates first_fail-1 entries have been successfully processed
-- and during processing of entries[first_fail], the error occurred. So the batch processor
-- only retries for the entries having index >= first_fail as per the retry policy.
end
batch_processor_manager:add_entry_to_new_processor(conf, entry, ctx, func)
end

The batch processor's configuration will be set inside the plugin's configuration. For example:

curl http://127.0.0.1:9180/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
"plugins": {
"http-logger": {
"uri": "http://mockbin.org/bin/:ID",
"batch_max_size": 10,
"max_retry_count": 1
}
},
"upstream": {
"type": "roundrobin",
"nodes": {
"127.0.0.1:1980": 1
}
},
"uri": "/hello"
}'

If your plugin only uses one global batch processor, you can also use the processor directly:

local entry = {...} -- data to log
if log_buffer then
log_buffer:push(entry)
return
end

local config_bat = {
name = config.name,
retry_delay = config.retry_delay,
...
}

local err
-- entries is an array table of entry, which can be processed in batch
local func = function(entries)
...
return true
-- return false, err_msg, first_fail if failed
end
log_buffer, err = batch_processor:new(func, config_bat)

if not log_buffer then
core.log.warn("error when creating the batch processor: ", err)
return
end

log_buffer:push(entry)

Note: Please make sure the batch max size (entry count) is within the limits of the function execution. The timer to flush the batch runs based on the inactive_timeout configuration. Thus, for optimal usage, keep the inactive_timeout smaller than the buffer_duration.