--[[
Copyright (C) 2013-2018 Draios Inc dba Sysdig.

This file is part of sysdig.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

--]]

-- Chisel description
description = "Given a filter on the command line, this chisel saves the events that are in a time range around filter matches, and that are on the SAME process/thread. The time range can be adjusted with the dump_range_ms argument. For example, 'sysdig -c around evt.type=open and evt.failed=true' will save two seconds of activity around every failed open.";
short_description = "Export to file the events around the time range where the given filter matches.";
category = "Misc";
		
-- Argument list
args =
{
	{
		name = "dump_file_name",
		description = "The name of the file where the chisel will write the events related to each syslog entry.",
		argtype = "string",
		optional = false
	},
	{
		name = "dump_range_ms",
		description = "The time interval to capture *before* and *after* each event, in milliseconds. For example, 500 means that 1 second around each displayed event (.5s before and .5s after) will be saved to <dump_file_name>. The default value for dump_range_ms is 1000.",
		argtype = "int",
		optional = true
	},
}
-- Imports and globals
require "common"
terminal = require "ansiterminal"
terminal.enable_color(true)
local dump_file_name = nil
local dump_range_ms = "1000"
local entrylist = {}
local capturing = false

-- Argument notification callback
function on_set_arg(name, val)
	if name == "dump_file_name" then
		dump_file_name = val
		return true
	elseif name == "dump_range_ms" then
		dump_range_ms = val
		return true
	end

	return false
end

-- Initialization callback
function on_init()	
	-- Request the fields that we need
	fpname = chisel.request_field("proc.name")
	ftid = chisel.request_field("thread.tid")
	fetime = chisel.request_field("evt.time")

	is_tty = sysdig.is_tty()
	
	if sysdig.get_filter() == "" then
		print("no filter specified")
		return false
	end
	
	return true
end

-- Final chisel initialization
function on_capture_start()
	if sysdig.is_live() then
		print("live capture not supported")
		return false
	end
	
	capturing = true

	return true
end

-- Event parsing callback
function on_event()	
	-- Extract the event details
	local pname = evt.field(fpname)
	local tid = evt.field(ftid)
	local etime = evt.field(fetime)
	
	if pname == nil then
		pname = "<NA>"
	end
	
	print(etime .. " " .. pname .. "(" .. tid .. ")")
	
	local hi, low = evt.get_ts()
	local tid = evt.field(ftid)
	table.insert(entrylist, {hi, low, tid})

	return true
end

-- Called by the engine at the end of the capture (Ctrl-C)
function on_capture_end()
	if is_tty then
		print(terminal.reset)
	end

	if capturing then
		local sn = sysdig.get_evtsource_name()

		local args = "-F -r" .. sn .. " -w" .. dump_file_name .. " "
		
		for i, v in ipairs(entrylist) do
			if i ~= 1 then
				args = args .. " or "
			end
			
			args = args .. "(evt.around[" .. ts_to_str(v[1], v[2]) .. "]=" .. dump_range_ms .. " and thread.tid=" .. v[3] .. ")"
		end		

		print("\nSaving events around " .. #entrylist .. " syslog entries to " .. dump_file_name)
		sysdig.run_app(args)
	end
end
