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# et (et v1.8)

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Main API of the Event Trace (ET) application

Interface module for the Event Trace (ET) application

## Summary

### Types

actor()
level()

### Functions

phone_home(DetailLevel, FromTo, Label, Contents)

Equivalent to `phone_home/5`.

phone_home(DetailLevel, From, To, Label, Contents)

These functions sends a signal to the outer space and the caller hopes that someone is listening. In other words, they invoke `et:trace_me/4` and `et:trace_me/5` respectively.

report_event(DetailLevel, FromTo, Label, Contents)

Equivalent to `report_event/5`.

report_event(DetailLevel, From, To, Label, Contents)

Deprecated functions which for the time being are kept for backwards compatibility. Invokes `et:trace_me/4` and `et:trace_me/5` respectively.

trace_me(DetailLevel, FromTo, Label, Contents)

Invokes `et:trace_me/5` with both `From` and `To` set to `FromTo`.

trace_me(DetailLevel, From, To, Label, Contents)

A function that is intended to be traced.

## Types

# actor()

(not exported)

    -type actor() :: term().

# level()

(not exported)

    -type level() :: 0..100.

## Functions

# phone_home(DetailLevel, FromTo, Label, Contents)

    -spec phone_home(DetailLevel, FromTo, Label, Contents) -> hopefully_traced
                        when
                            DetailLevel :: level(),
                            FromTo :: actor(),
                            Label :: atom() | string() | term(),
                            Contents :: [{Key :: term(), Value :: term()}] | term().

Equivalent to `phone_home/5`.

# phone_home(DetailLevel, From, To, Label, Contents)

    -spec phone_home(DetailLevel, From, To, Label, Contents) -> hopefully_traced
                        when
                            DetailLevel :: level(),
                            From :: actor(),
                            To :: actor(),
                            Label :: atom() | string() | term(),
                            Contents :: [{Key :: term(), Value :: term()}] | term().

These functions sends a signal to the outer space and the caller hopes that someone is listening. In other words, they invoke `et:trace_me/4` and `et:trace_me/5` respectively.

# report_event(DetailLevel, FromTo, Label, Contents)

    -spec report_event(DetailLevel, FromTo, Label, Contents) -> hopefully_traced
                          when
                              DetailLevel :: level(),
                              FromTo :: actor(),
                              Label :: atom() | string() | term(),
                              Contents :: [{Key :: term(), Value :: term()}] | term().

Equivalent to `report_event/5`.

# report_event(DetailLevel, From, To, Label, Contents)

    -spec report_event(DetailLevel, From, To, Label, Contents) -> hopefully_traced
                          when
                              DetailLevel :: level(),
                              From :: actor(),
                              To :: actor(),
                              Label :: atom() | string() | term(),
                              Contents :: [{Key :: term(), Value :: term()}] | term().

Deprecated functions which for the time being are kept for backwards compatibility. Invokes `et:trace_me/4` and `et:trace_me/5` respectively.

# trace_me(DetailLevel, FromTo, Label, Contents)

(since OTP R13B04)

    -spec trace_me(DetailLevel, FromTo, Label, Contents) -> hopefully_traced
                      when
                          DetailLevel :: level(),
                          FromTo :: actor(),
                          Label :: atom() | string() | term(),
                          Contents :: [{Key :: term(), Value :: term()}] | term().

Invokes `et:trace_me/5` with both `From` and `To` set to `FromTo`.

# trace_me(DetailLevel, From, To, Label, Contents)

(since OTP R13B04)

    -spec trace_me(DetailLevel, From, To, Label, Contents) -> hopefully_traced
                      when
                          DetailLevel :: level(),
                          From :: actor(),
                          To :: actor(),
                          Label :: atom() | string() | term(),
                          Contents :: [{Key :: term(), Value :: term()}] | term().

A function that is intended to be traced.

This function is intended to be invoked at strategic places in user applications in order to enable simplified tracing. The functions are extremely light weight as they do nothing besides returning an atom. The functions are designed for being traced. The global tracing mechanism in `et_collector` defaults to set its trace pattern to these functions.

The label is intended to provide a brief summary of the event. It is preferred to use an atom but a string would also do.

The contents can be any term but in order to simplify post processing of the traced events, a plain list of {Key, Value} tuples is preferred.

Some events, such as messages, are directed from some actor to another. Other events (termed actions) may be undirected and only have one actor.