[lttng-dev] [PATCH v2 lttng-tools] Filter: Notify the user when a filter is already enabled on event(s)

[David Goulet]

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Hash: SHA512

Merged!

Christian Babeux:
> When using the enable-event command in conjunction with the
> --filter option, a user can specify a filter expression to refine
> the trace output.
> 
> As stated in the lttng(1) man page, only the first activation of a
> filter on an event will work. Subsequent activation of any filter
> expression on the same event will fail.
> 
> e.g:
> 
>> lttng enable-event app:tp -s session -u --filter 'somefield >
>> 42'
> 
> # Case: invalid filter expression
>> lttng enable-event app:tp -s session -u --filter 'invalid
>> expression'
> Error: Error setting filter Warning: Some command(s) went wrong
> 
>> ...
> 
> # Case: filter already enabled for event app:tp
>> lttng enable-event app:tp -s session -u --filter 'someotherfield
>> < 42'
> Error: Error setting filter Warning: Some command(s) went wrong
> 
> This commit differentiate the case where a filter was already set
> for the specified event from the generic 'Error setting filter'
> error message.
> 
> e.g:
> 
>> lttng enable-event app:tp -s session -u --filter 'somefield >
>> 42'
> 
> # Case: invalid filter expression
>> lttng enable-event app:tp -s session -u --filter 'invalid
>> expression'
> Error: Error setting filter Warning: Some command(s) went wrong
> 
>> ...
> 
> # Case: filter already enabled for event app:tp
>> lttng enable-event app:tp -s session -u --filter 'someotherfield
>> < 42'
> Error: Filter on event app:tp is already enabled (channel 0,
> session session) Warning: Some command(s) went wrong
> 
> Signed-off-by: Christian Babeux <christian.babeux at efficios.com> 
> --- src/bin/lttng/commands/enable_events.c | 22
> ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2
> deletions(-)
> 
> diff --git a/src/bin/lttng/commands/enable_events.c
> b/src/bin/lttng/commands/enable_events.c index a2c8a68..5a81fdb
> 100644 --- a/src/bin/lttng/commands/enable_events.c +++
> b/src/bin/lttng/commands/enable_events.c @@ -384,7 +384,16 @@
> static int enable_events(char *session_name) ret =
> lttng_set_event_filter(handle, ev.name, channel_name, opt_filter); 
> if (ret < 0) { -				ERR("Error setting filter"); +				switch (-ret)
> { +				case LTTCOMM_FILTER_EXIST: +					ERR("Filter on events is
> already enabled (channel %s, session %s)", +						channel_name,
> session_name); +					break; +				default: +					ERR("Error setting
> filter"); +					break; +				} + ret = -1; goto error; } @@ -554,7
> +563,16 @@ static int enable_events(char *session_name) ret =
> lttng_set_event_filter(handle, ev.name, channel_name, opt_filter); 
> if (ret < 0) { -				ERR("Error setting filter"); +				switch (-ret)
> { +				case LTTCOMM_FILTER_EXIST: +					ERR("Filter on event %s is
> already enabled (channel %s, session %s)", +						event_name,
> channel_name, session_name); +					break; +				default: +
> ERR("Error setting filter"); +					break; +				} + ret = -1; goto
> error; }
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