Eliza Weisman b2c53987d9
trace: Add shorthand for field::display and field::debug (#1088)
## Motivation

In `tokio-trace`, field values may be recorded as either a subset of
Rust primitive types or as `fmt::Display` and `fmt::Debug`
implementations. Currently, `tokio-trace` provides the `field::display`
and `field::debug` functions which wrap a type with a type that
implements `Value` using the wrapped type's `fmt::Display` or
`fmt::Debug` implementation. However, importing and using these
functions adds unnecessary boilerplate. 

In #1081, @jonhoo suggested adding shorthand syntax to the macros,
similar to that used by the `slog` crate, as a solution for the
wordiness of the current API.

## Solution

This branch adds `?` and `%` sigils to field values in the span and
event macros, which expand to the `field::debug` and `field::display`
wrappers, respectively. The shorthand sigils may be used in any position
where the macros take a field value.

For example:
```rust
trace_span!("foo", my_field = ?something, ...); // shorthand for `debug`
info!(foo = %value, bar = false, ...) // shorthand for `display`
```

Adding this shorthand required a fairly large change to how field
key-value pairs are handled by the macros --- since `%foo` and `%foo`
are not valid Rust expressions, we can no longer match repeated 
`$ident = $expr` patterns, and must now match field lists as repeated
token trees. The inner helper macros for constructing `FieldSet`s and
`ValueSet`s have to parse the token trees recursively. This added a
decent chunk of complexity, but fortunately we have a large number of
compile tests for the macros and I'm quite confident that all existing
invocations will still work.

Closes #1081

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
2019-05-21 10:31:48 -07:00

612 lines
16 KiB
Rust

#[macro_use]
extern crate tokio_trace;
mod support;
use self::support::*;
use std::thread;
use tokio_trace::{
field::{debug, display},
subscriber::with_default,
Level, Span,
};
#[test]
fn handles_to_the_same_span_are_equal() {
// Create a mock subscriber that will return `true` on calls to
// `Subscriber::enabled`, so that the spans will be constructed. We
// won't enter any spans in this test, so the subscriber won't actually
// expect to see any spans.
with_default(subscriber::mock().run(), || {
let foo1 = span!(Level::TRACE, "foo");
let foo2 = foo1.clone();
// Two handles that point to the same span are equal.
assert_eq!(foo1, foo2);
});
}
#[test]
fn handles_to_different_spans_are_not_equal() {
with_default(subscriber::mock().run(), || {
// Even though these spans have the same name and fields, they will have
// differing metadata, since they were created on different lines.
let foo1 = span!(Level::TRACE, "foo", bar = 1u64, baz = false);
let foo2 = span!(Level::TRACE, "foo", bar = 1u64, baz = false);
assert_ne!(foo1, foo2);
});
}
#[test]
fn handles_to_different_spans_with_the_same_metadata_are_not_equal() {
// Every time time this function is called, it will return a _new
// instance_ of a span with the same metadata, name, and fields.
fn make_span() -> Span {
span!(Level::TRACE, "foo", bar = 1u64, baz = false)
}
with_default(subscriber::mock().run(), || {
let foo1 = make_span();
let foo2 = make_span();
assert_ne!(foo1, foo2);
// assert_ne!(foo1.data(), foo2.data());
});
}
#[test]
fn spans_always_go_to_the_subscriber_that_tagged_them() {
let subscriber1 = subscriber::mock()
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run();
let subscriber2 = subscriber::mock().run();
let foo = with_default(subscriber1, || {
let foo = span!(Level::TRACE, "foo");
foo.enter(|| {});
foo
});
// Even though we enter subscriber 2's context, the subscriber that
// tagged the span should see the enter/exit.
with_default(subscriber2, move || foo.enter(|| {}));
}
#[test]
fn spans_always_go_to_the_subscriber_that_tagged_them_even_across_threads() {
let subscriber1 = subscriber::mock()
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run();
let foo = with_default(subscriber1, || {
let foo = span!(Level::TRACE, "foo");
foo.enter(|| {});
foo
});
// Even though we enter subscriber 2's context, the subscriber that
// tagged the span should see the enter/exit.
thread::spawn(move || {
with_default(subscriber::mock().run(), || {
foo.enter(|| {});
})
})
.join()
.unwrap();
}
#[test]
fn dropping_a_span_calls_drop_span() {
let (subscriber, handle) = subscriber::mock()
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
let span = span!(Level::TRACE, "foo");
span.enter(|| {});
drop(span);
});
handle.assert_finished();
}
#[test]
fn span_closes_after_event() {
let (subscriber, handle) = subscriber::mock()
.enter(span::mock().named("foo"))
.event(event::mock())
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "foo").enter(|| {
event!(Level::DEBUG, {}, "my event!");
});
});
handle.assert_finished();
}
#[test]
fn new_span_after_event() {
let (subscriber, handle) = subscriber::mock()
.enter(span::mock().named("foo"))
.event(event::mock())
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.enter(span::mock().named("bar"))
.exit(span::mock().named("bar"))
.drop_span(span::mock().named("bar"))
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "foo").enter(|| {
event!(Level::DEBUG, {}, "my event!");
});
span!(Level::TRACE, "bar").enter(|| {});
});
handle.assert_finished();
}
#[test]
fn event_outside_of_span() {
let (subscriber, handle) = subscriber::mock()
.event(event::mock())
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
debug!("my event!");
span!(Level::TRACE, "foo").enter(|| {});
});
handle.assert_finished();
}
#[test]
fn cloning_a_span_calls_clone_span() {
let (subscriber, handle) = subscriber::mock()
.clone_span(span::mock().named("foo"))
.run_with_handle();
with_default(subscriber, || {
let span = span!(Level::TRACE, "foo");
let _span2 = span.clone();
});
handle.assert_finished();
}
#[test]
fn drop_span_when_exiting_dispatchers_context() {
let (subscriber, handle) = subscriber::mock()
.clone_span(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.run_with_handle();
with_default(subscriber, || {
let span = span!(Level::TRACE, "foo");
let _span2 = span.clone();
drop(span);
});
handle.assert_finished();
}
#[test]
fn clone_and_drop_span_always_go_to_the_subscriber_that_tagged_the_span() {
let (subscriber1, handle1) = subscriber::mock()
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.clone_span(span::mock().named("foo"))
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.run_with_handle();
let subscriber2 = subscriber::mock().done().run();
let foo = with_default(subscriber1, || {
let foo = span!(Level::TRACE, "foo");
foo.enter(|| {});
foo
});
// Even though we enter subscriber 2's context, the subscriber that
// tagged the span should see the enter/exit.
with_default(subscriber2, move || {
let foo2 = foo.clone();
foo.enter(|| {});
drop(foo);
drop(foo2);
});
handle1.assert_finished();
}
#[test]
fn span_closes_when_exited() {
let (subscriber, handle) = subscriber::mock()
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
let foo = span!(Level::TRACE, "foo");
foo.enter(|| {});
drop(foo);
});
handle.assert_finished();
}
#[test]
fn moved_field() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock().named("foo").with_field(
field::mock("bar")
.with_value(&display("hello from my span"))
.only(),
),
)
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
let from = "my span";
let span = span!(
Level::TRACE,
"foo",
bar = display(format!("hello from {}", from))
);
span.enter(|| {});
});
handle.assert_finished();
}
#[test]
fn dotted_field_name() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock()
.named("foo")
.with_field(field::mock("fields.bar").with_value(&true).only()),
)
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "foo", fields.bar = true);
});
handle.assert_finished();
}
#[test]
fn borrowed_field() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock().named("foo").with_field(
field::mock("bar")
.with_value(&display("hello from my span"))
.only(),
),
)
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
let from = "my span";
let mut message = format!("hello from {}", from);
let span = span!(Level::TRACE, "foo", bar = display(&message));
span.enter(|| {
message.insert_str(10, " inside");
});
});
handle.assert_finished();
}
#[test]
// If emitting log instrumentation, this gets moved anyway, breaking the test.
#[cfg(not(feature = "log"))]
fn move_field_out_of_struct() {
use tokio_trace::field::debug;
#[derive(Debug)]
struct Position {
x: f32,
y: f32,
}
let pos = Position {
x: 3.234,
y: -1.223,
};
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock().named("foo").with_field(
field::mock("x")
.with_value(&debug(3.234))
.and(field::mock("y").with_value(&debug(-1.223)))
.only(),
),
)
.new_span(
span::mock()
.named("bar")
.with_field(field::mock("position").with_value(&debug(&pos)).only()),
)
.run_with_handle();
with_default(subscriber, || {
let pos = Position {
x: 3.234,
y: -1.223,
};
let foo = span!(Level::TRACE, "foo", x = debug(pos.x), y = debug(pos.y));
let bar = span!(Level::TRACE, "bar", position = debug(pos));
foo.enter(|| {});
bar.enter(|| {});
});
handle.assert_finished();
}
#[test]
fn add_field_after_new_span() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock()
.named("foo")
.with_field(field::mock("bar").with_value(&5).only()),
)
.record(
span::mock().named("foo"),
field::mock("baz").with_value(&true).only(),
)
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
let span = span!(Level::TRACE, "foo", bar = 5, baz);
span.record("baz", &true);
span.enter(|| {})
});
handle.assert_finished();
}
#[test]
fn add_fields_only_after_new_span() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo"))
.record(
span::mock().named("foo"),
field::mock("bar").with_value(&5).only(),
)
.record(
span::mock().named("foo"),
field::mock("baz").with_value(&true).only(),
)
.enter(span::mock().named("foo"))
.exit(span::mock().named("foo"))
.drop_span(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
let span = span!(Level::TRACE, "foo", bar, baz);
span.record("bar", &5);
span.record("baz", &true);
span.enter(|| {})
});
handle.assert_finished();
}
#[test]
fn new_span_with_target_and_log_level() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock()
.named("foo")
.with_target("app_span")
.at_level(Level::DEBUG),
)
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::DEBUG, target: "app_span", "foo");
});
handle.assert_finished();
}
#[test]
fn explicit_root_span_is_root() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo").with_explicit_parent(None))
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, parent: None, "foo");
});
handle.assert_finished();
}
#[test]
fn explicit_root_span_is_root_regardless_of_ctx() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo"))
.enter(span::mock().named("foo"))
.new_span(span::mock().named("bar").with_explicit_parent(None))
.exit(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "foo").enter(|| {
span!(Level::TRACE, parent: None, "bar");
})
});
handle.assert_finished();
}
#[test]
fn explicit_child() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo"))
.new_span(span::mock().named("bar").with_explicit_parent(Some("foo")))
.done()
.run_with_handle();
with_default(subscriber, || {
let foo = span!(Level::TRACE, "foo");
span!(Level::TRACE, parent: foo.id(), "bar");
});
handle.assert_finished();
}
#[test]
fn explicit_child_regardless_of_ctx() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo"))
.new_span(span::mock().named("bar"))
.enter(span::mock().named("bar"))
.new_span(span::mock().named("baz").with_explicit_parent(Some("foo")))
.exit(span::mock().named("bar"))
.done()
.run_with_handle();
with_default(subscriber, || {
let foo = span!(Level::TRACE, "foo");
span!(Level::TRACE, "bar").enter(|| span!(Level::TRACE, parent: foo.id(), "baz"))
});
handle.assert_finished();
}
#[test]
fn contextual_root() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo").with_contextual_parent(None))
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "foo");
});
handle.assert_finished();
}
#[test]
fn contextual_child() {
let (subscriber, handle) = subscriber::mock()
.new_span(span::mock().named("foo"))
.enter(span::mock().named("foo"))
.new_span(
span::mock()
.named("bar")
.with_contextual_parent(Some("foo")),
)
.exit(span::mock().named("foo"))
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "foo").enter(|| {
span!(Level::TRACE, "bar");
})
});
handle.assert_finished();
}
#[test]
fn display_shorthand() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock().named("my_span").with_field(
field::mock("my_field")
.with_value(&display("hello world"))
.only(),
),
)
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "my_span", my_field = %"hello world");
});
handle.assert_finished();
}
#[test]
fn debug_shorthand() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock().named("my_span").with_field(
field::mock("my_field")
.with_value(&debug("hello world"))
.only(),
),
)
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "my_span", my_field = ?"hello world");
});
handle.assert_finished();
}
#[test]
fn both_shorthands() {
let (subscriber, handle) = subscriber::mock()
.new_span(
span::mock().named("my_span").with_field(
field::mock("display_field")
.with_value(&display("hello world"))
.and(field::mock("debug_field").with_value(&debug("hello world")))
.only(),
),
)
.done()
.run_with_handle();
with_default(subscriber, || {
span!(Level::TRACE, "my_span", display_field = %"hello world", debug_field = ?"hello world");
});
handle.assert_finished();
}