## Output Traces

An output Trace is a trace, indentified by a URI, that a python-libtrace progrm can write Packets to. As with input traces, you must create (output_trace() ) and start (output_trace.start)() an output trace before you can write Packets to it with output_trace.write_packet().

### Class OutputTrace

Global Constants
compression types | See the libtrace documentation for more details
| NO_COMPRESSION | Write uncompressed trace
| ZLIB_COMPRESSION | Write using zlib compression
| BZIP2_COMPRESSION | Write using bzip2 compresion
| LZO_COMPRESSION | Write using LZO compression

Class Methods
output_trace() | output_trace.new(uri) -> aNewOutputTrace
| Returns a libtrace OutputTrace object. The object's name is given by a string containing its URI, e.g. pcapfile:xxx.pcap, int:eth0, ...
conf_file_flags() | output_trace.conf_file_flags(Integer)
| Sets file creation flags for an OutputTrace; e.g. O_APPEND or 0iii (linux user/group/other permissions). Throws a plt_exc_libtrace exception if the conf fails.
conf_compress_type() | output_trace.conf_compress_type(compression_type)
| Sets the compression type that libtrace will use when writing the OutputTrace. Throws a plt_exc_libtrace exception if the conf fails.
conf_compress_level() | output_trace.conf_compress_level(Integer)
| Sets the compression level that libtrace will use when writing the OutputTrace. Higher levels give more compression, but lower writing speed. Levels may be from 1 (minimum) to 9 (maximum), the default level is 5. Throws a plt_exc_libtrace exception if the conf fails.
start_output() | output_trace.start_output()
| Starts the sending of packets (from a live inteferace), or opens a trace file for writing. Throws a plt_exc_libtrace exception if the start fails.
close_output() | output_trace.close_output()
| Shuts down a live interface, or closes a trace file.
write_packet() | output_trace.write_packet(Packet)
| Writes the data from a Packet to an OutputTrace. Throws a plt_exc_libtrace exception if the write fails.

Nevil Brownlee
Thu, 17 Jul 14 (NZST)