snsh: Added '-q' to break program to REPL via keyboard #629
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Now you can run any Snabb-based program in a mode that supports
interrupting it with the keyboard (Control-\ i.e. SIGQUIT) such that
it leaves the breathe loop and enters an interactive read-eval-print
loop (REPL). Here you can poke around with arbitrary Lua expressions
and finally return back to the engine by pressing Control-d (EOF).
The argument -q (--sigquit-repl) enables a timer callback in the
engine that checks if SIGQUIT has been received and starts a
REPL. This can be combined with the -p (--program) argument to run
another program such as packetblaster or snabbnfv.
For example:
snabb snsh -q -p packetblaster replay 64.cap 0000:01:00.0
will run packetblaster but with the hook enabled such that each time
you press Control-\ the process will receive a SIGQUIT and enter the
REPL like this:
0000:01:00.1 TXDGPC (TX packets) 13,154,784 GOTCL (TX octets) 894,522,388
^\[snsh: SIGQUIT caught - entering REPL]
Snabb>
Note: SIGQUIT is detected by a hook function running on a timer and so
it is only effective when the engine's breathe loop is running. (The
REPL does not run inside a Unix signal handler -- the signal only sets
a flag saying that it should be started.)
Use a command-line syntax that supports saying what should happen when SIGQUIT is received. This is for future extensibility if we want to do something else than enter the REPL e.g. toggle debug printouts, enter a debugger, fork a child for offline debugging, etc.
lukego
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Dec 7, 2016
Re-enable lwaftr CSV stats
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Now you can run any Snabb-based program in a mode that supports
interrupting it with the keyboard (Control-\ i.e. SIGQUIT) such that
it leaves the breathe loop and enters an interactive read-eval-print
loop (REPL). Here you can poke around with arbitrary Lua expressions
and finally return back to the engine by pressing Control-d (EOF).
The
snshargument -q (--sigquit-repl) enables a timer callback in theengine that checks if SIGQUIT has been received and starts a
REPL. This can be combined with the -p (--program) argument to run
another program such as packetblaster or snabbnfv.
For example:
snabb snsh -q -p packetblaster replay 64.cap 0000:01:00.0
will run packetblaster but with the hook enabled such that each time
you press Control-\ the process will receive a SIGQUIT and enter the
REPL like this:
Note: SIGQUIT is detected by a hook function running on a timer and so
it is only effective when the engine's breathe loop is running. (The
REPL does not run inside a Unix signal handler -- the signal only sets
a flag saying that it should be started.)