Tail File Input (new line delimited)

todo: when more than line splitting is needed the file should be read in chunks and passed to a generic splitter buffer with a token/match specification and a find function similar to the Heka stream reader.

warning: if the file being tailed is not flushed on newline Lua reads and returns the partial line before the so it may be improperly split.

1. Sample Configuration

filename = "tail.lua"
ticker_interval = 1 -- poll once a second after hitting EOF

-- Name of the input file
input_filename = "/var/log/text.log"

-- Multi-line log support
-- delimiter = "^# User@Host:" -- optional if anchored at the beginning of the line it is treated as
                               -- a start of record delimiter and the line belongs to the next log
                               -- otherwise it is an end of record delimiter and the line belongs to
                               -- the current log. "^$" is special cased and is treated as an end of
                               -- line delimiter.
-- Consumes appended data as the file grows
-- Default:
-- follow = "descriptor" -- use "name" for rotated logs

-- Heka message table containing the default header values to use, if they are
-- not populated by the decoder. If 'Fields' is specified it should be in the
-- hashed based format see:  http://mozilla-services.github.io/lua_sandbox/heka/message.html
-- Default:
-- default_headers = nil

-- printf_messages = -- see: https://mozilla-services.github.io/lua_sandbox_extensions/lpeg/modules/lpeg/printf.html

-- Specifies a module that will decode the raw data and inject the resulting message.
-- Supports the same syntax as an individual sub decoder
-- see: https://mozilla-services.github.io/lua_sandbox_extensions/lpeg/io_modules/lpeg/sub_decoder_util.html
-- Default:
-- decoder_module = "decoders.payload"

-- Boolean, if true, any decode failure will inject a  message of Type "error",
-- with the Payload containing the error.
-- Default:
-- send_decode_failures = false

source code: tail.lua