#[macro_export]
/// This is a really simple macro to assert a snapshot of the logs.
/// To use it call `.with_subscriber(assert_snapshot_subscriber!())` in your test just before calling `await`.
/// This will assert a snapshot of the logs in pretty yaml format.
/// You can also use subscriber::with_default(assert_snapshot_subscriber!(), || { ... }) to assert the logs in non async code.
macro_rules! assert_snapshot_subscriber {
() => {
$crate::assert_snapshot_subscriber!(tracing_core::LevelFilter::INFO, {})
};
($redactions:tt) => {
$crate::assert_snapshot_subscriber!(tracing_core::LevelFilter::INFO, $redactions)
};
($level:expr) => {
$crate::assert_snapshot_subscriber!($level, {})
};
($level:expr, $redactions:tt) => {
$crate::logging::test::SnapshotSubscriber::create_subscriber($level, |yaml| {
insta::with_settings!({sort_maps => true}, {
// the tests here will force maps to sort
let mut settings = insta::Settings::clone_current();
settings.set_snapshot_suffix("logs");
settings.set_sort_maps(true);
settings.bind(|| {
insta::assert_yaml_snapshot!(yaml, $redactions);
});
});
})
};
}
#[cfg(test)]
pub(crate) mod test {
use std::sync::Arc;
use std::sync::Mutex;
use serde_json::Value;
use tracing_core::LevelFilter;
use tracing_core::Subscriber;
use tracing_subscriber::layer::SubscriberExt;
pub(crate) struct SnapshotSubscriber {
buffer: Arc<Mutex<Vec<u8>>>,
assertion: fn(Value),
}
impl std::io::Write for SnapshotSubscriber {
fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
let buf_len = buf.len();
self.buffer.lock().unwrap().append(&mut buf.to_vec());
Ok(buf_len)
}
fn flush(&mut self) -> std::io::Result<()> {
Ok(())
}
}
impl Drop for SnapshotSubscriber {
fn drop(&mut self) {
let log = String::from_utf8(self.buffer.lock().unwrap().to_vec()).unwrap();
let parsed: Value = if log.is_empty() {
serde_json::json!([])
} else {
let parsed_log: Vec<Value> = log
.lines()
.map(|line| {
let mut line: Value = serde_json::from_str(line).unwrap();
// move the message field to the top level
let fields = line
.as_object_mut()
.unwrap()
.get_mut("fields")
.unwrap()
.as_object_mut()
.unwrap();
let message = fields.remove("message").unwrap_or_default();
line.as_object_mut()
.unwrap()
.insert("message".to_string(), message);
line
})
.collect();
serde_json::json!(parsed_log)
};
(self.assertion)(parsed)
}
}
impl SnapshotSubscriber {
pub(crate) fn create_subscriber(
level: LevelFilter,
assertion: fn(Value),
) -> impl Subscriber {
let collector = Self {
buffer: Arc::new(Mutex::new(Vec::new())),
assertion,
};
tracing_subscriber::registry::Registry::default()
.with(level)
.with(
tracing_subscriber::fmt::Layer::default()
.json()
.without_time()
.with_target(false)
.with_file(false)
.with_line_number(false)
.with_writer(Mutex::new(collector)),
)
}
}
}