Struct merino_integration_tests::LogWatcher

pub struct LogWatcher {
    buf: Arc<Mutex<Vec<u8>>>,
    events: Vec<TracingJsonEvent>,
}

Helper to collect events emitted by Tracing and later make assertions about the collected events.

Fields

buf: Arc<Mutex<Vec<u8>>>

The raw bytes received from Tracing. Should represent new-line separated JSON objects.

events: Vec<TracingJsonEvent>

Events serialized from buf. As valid JSON objects are parsed from buf, the corresponding bytes are removed from buf. This way if there are any partial writes, only the complete objects are processed from the buffer, leaving incomplete objects in place.

Implementations

impl LogWatcher

pub fn with_events(events: Vec<TracingJsonEvent>) -> Self

Make a new LogWatcher with some events pre-populated. Primarily for testing LogWatcher itself.

pub fn events(&mut self) -> Iter<'_, TracingJsonEvent>

Iterate over the events collected so far by this log watcher.

pub fn has<F>(&mut self, predicate: F) -> bool where
    F: FnMut(&TracingJsonEvent) -> bool, 

Test if any event this logger received matches predicate.

Example

// assert!(log_watcher.has(|msg| msg.field_contains("message", "request success")));

fn convert_events(&mut self)

Iterate through self.buf to convert newline separated, completed JSON objects into TracingJsonEvent instances that are placed in self.events.

Trait Implementations

impl Default for LogWatcher

fn default() -> LogWatcher

Returns the “default value” for a type.

impl MakeWriter for LogWatcher

type Writer = LogWatcherWriter

The concrete io::Write implementation returned by make_writer.

fn make_writer(&self) -> Self::Writer

Returns an instance of Writer.

fn make_writer_for(&self, meta: &Metadata<'_>) -> Self::Writer

Returns a Writer for writing data from the span or event described by the provided Metadata.