et_selector

MODULE

et_selector

MODULE SUMMARY

Define event transforms and trace patterns

DESCRIPTION

EXPORTS

make_pattern(RawPattern) -> TracePattern

Types:

RawPattern = detail_level()

TracePattern = erlang_trace_pattern_match_spec()

detail_level() = min | max | integer(X) when X >= 0, X =< 100

Makes a trace pattern suitable to feed change_pattern/1

Min detail level deactivates tracing of calls to et:trace_me/4,5

Max detail level activates tracing of all calls to et:trace_me/4,5

integer(X) detail level activates tracing of all calls to et:trace_me/4,5 whose detail level argument is lesser than X.

See also erlang:trace_pattern/2 for more info about its match_spec()

change_pattern(Pattern) -> ok

Types:

Pattern = detail_level() | empty_match_spec() | erlang_trace_pattern_match_spec()

detail_level() = min | max | integer(X) when X >= 0, X =< 100

empty_match_spec() = []

Activates/deactivates tracing by changing the current trace pattern.

min detail level deactivates tracing of calls to et:trace_me/4,5

max detail level activates tracing of all calls to et:trace_me/4,5

integer(X) detail level activates tracing of all calls to et:trace_me/4,5 whose detail level argument is lesser than X.

An empty match spec deactivates tracing of calls to et:trace_me/4,5

Other match specs activates tracing of calls to et:trace_me/4,5 accordingly with erlang:trace_pattern/2.

parse_event(Mod, ValidTraceData) -> false | true | {true, Event}

Types:

Mod = module_name() | undefined <v>module_name() = atom() <v>ValidTraceData = erlang_trace_data() | record(event)

erlang_trace_data() = {trace, Pid, Label, Info} | {trace, Pid, Label, Info, Extra} | {trace_ts, Pid, Label, Info, ReportedTS} | {trace_ts, Pid, Label, Info, Extra, ReportedTS} | {seq_trace, Label, Info} | {seq_trace, Label, Info, ReportedTS} | {drop, NumberOfDroppedItems}

Transforms trace data and makes an event record out of it.

See erlang:trace/3 for more info about the semantics of the trace data.

An event record consists of the following fields:

detail_level: Noise has a high level as opposed to essentials.
trace_ts: Time when the trace was generated. Same as event_ts if omitted in trace data.
event_ts: Time when the event record was created.
from: From actor, such as sender of a message.
to: To actor, such as receiver of message.
label: Label intended to provide a brief event summary.
contents: All nitty gritty details of the event.

See et:trace_me/4and et:trace_me/5 for details.

Returns:

{true, Event}: where Event is an #event{} record representing the trace data
true: means that the trace data already is an event record and that it is valid as it is. No transformation is needed.
false: means that the trace data is uninteresting and should be dropped