[lttng-dev] [RFC lttng-tools] Save and restore feature

[jeremie.galarneau@efficios.com (Jérémie Galarneau)]

Hi all,

I'd like to submit the following patches from my personal lttng-tools
branch for merge in master[1].

a923fbe - session_find_by_name does not need a non-const name parameter
7fca51a - Fix: tcp4 and net4 protocol support in uri_parse
e6fc6a3 - Send filter expression string to session daemon
904fbd7 - Add a dependency to libxml2
dc9e590 - Add a config_writer API based on libxml2
c3e9d95 - Add session configuration XSD
afced3a - Add a save API to lttng-ctl
a933bdf - Add session configuration save feature to session daemon
79a9e3d - Add a save command based on the save API to the lttng client
7ae1b6b - Add session configuration load capability to libconfig
7e4b250 - Add load command to the lttng client

These patches add the ability to save and restore session
configurations using the lttng command-line client. The session
configurations are saved as XML following a schema which is included
in the patches.

Quick user guide to try out this feature:

# Create a session as usual
lttng create my_session
lttng enable-event -k -a
lttng enable-event -u -a
lttng add-context -k -t perf:cache-misses

# Save.. This will create a my_session.lttng file under ~/.lttng/sessions
lttng save my_session

# Destroy the session
lttng destroy

# Load the session... lttng will look in the user's home directory and
# in the system trace configuration directory (/etc/lttng/sessions)
for a session
# matching this name and load it.
lttng load my_session

Looking forward to your comments,
J?r?mie

[1] https://github.com/jgalar/lttng-tools.git

-- 
J?r?mie Galarneau
EfficiOS Inc.
http://www.efficios.com