decode_json_metric.lua

require "cjson"

local fields = {
    values = {},
    interval = 0,
    plugin = "",
    plugin_instance = "",
    ["type"] = "",
    type_instance = ""
}

local msg = {
    Fields = fields,
    Timestamp = nil,
    Hostname = nil,
    Type = "metric_message_type"
}

function process_message()
    local payload = read_message("Payload")
    local ok, metrics = pcall(cjson.decode, payload)
    if not ok then return -1 end
    for i, metric in ipairs(metrics) do
        fields.values = metric.values
        fields.interval = metric.interval
        fields.plugin = metric.plugin
        fields.plugin_instance = metric.plugin_instance
        fields.type = metric.type
        fields.type_instance = metric.type_instance
        local time = tonumber(metric.time)
        msg.Timestamp = time
        msg.Hostname = metric.host
        inject_message(msg)
    end
    return 0
end