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History

subscriber: handle explicit event parents properly in formatters (#767 )

## Motivation

Currently, the default formatter implementations in
`tracing-subscriber`'s `fmt` module do not handle explicitly set parent
spans for events, such as

```rust
let span = tracing::info_span!("some_interesting_span");
tracing::info!(parent: &span, "something is happening!");
```

Instead, when formatting the span context of an event, the context is
_always_ generated from the current span, even when the event has an
overridden parent. This is not correct.

## Solution

This branch changes the default context formatters to use the explicit
parent ID, if it is present. Otherwise, the contexual parent is used, as
it was previously.

I've also added tests ensuring that this works correctly, and removed
some workarounds for the previous incorrect behavior from the examples.

Fixes #766

Signed-off-by: Eliza Weisman <eliza@buoyant.io>

2020-06-24 12:47:33 -07:00

examples

subscriber: handle explicit event parents properly in formatters (#767 )

2020-06-24 12:47:33 -07:00

Cargo.toml

subscriber: prepare to release 0.2.6 (#757 )

2020-06-19 09:55:47 -07:00

README.md

examples: add tokio-spawny-thing; some chores (#759 )

2020-06-22 12:40:16 -04:00

README.md

Tracing Examples

This directory contains a collection of examples that demonstrate the use of the tracing ecosystem:

tracing:
- counters: Implements a very simple metrics system to demonstrate how subscribers can consume field values as typed data.
- sloggish: A demo Subscriber implementation that mimics the output of slog-term's Compact formatter.
tracing-attributes:
- attrs-basic: A simple example of the #[instrument] attribute.
- attrs-args: An example implementing a simple recursive calculation of Fibonacci numbers, to demonstrate how the #[instrument] attribute can record function arguments.
tracing-subscriber:
- fmt: Demonstrates the use of the fmt module in tracing-subscriber, which provides a subscriber implementation that logs traces to the console.
- fmt-stderr: Demonstrates overriding the output stream used by the fmt subscriber.
- fmt-custom-field: Demonstrates overriding how the fmt subscriber formats fields on spans and events.
- fmt-custom-event: Demonstrates overriding how the fmt subscriber formats events.
- subscriber-filter: Demonstrates the tracing-subscriber::filter module, which provides a layer which adds configurable filtering to a subscriber implementation.
- tower-load: Demonstrates how dynamically reloadable filters can be used to debug a server under load in production.
tracing-futures:
- spawny-thing: Demonstrates the use of the #[instrument] attribute macro asynchronous functions.
- tokio-spawny-thing.rs: Similar to spawny-thingy, but with the additional demonstration instrumenting concurrent tasks created with tokio::spawn.
- futures-proxy-server: Demonstrates the use of tracing-futures by implementing a simple proxy server, based on this example from tokio.
- async_fn: Demonstrates how asynchronous functions can be instrumented.
- echo: Demonstrates a tracing-instrumented variant of Tokio's echo example.
tracing-flame:
- infero-flame: Demonstrates the use of tracing-flame to generate a flamegraph from spans.
tracing-tower:
- tower-client: Demonstrates the use of tracing-tower to instrument a simple tower HTTP/1.1 client.
- tower-server: Demonstrates the use of tracing-tower to instrument a simple tower HTTP/1.1 server.
tracing-serde:
- serde-yak-shave: Demonstrates the use of tracing-serde by implementing a subscriber that emits trace output as JSON.
tracing-log:
- hyper-echo: Demonstrates how tracing-log can be used to record unstructured logs from dependencies as tracing events, by instrumenting this example from hyper, and using tracing-log to record logs emitted by hyper.
tracing-opentelemetry:
- opentelemetry: Demonstrates how tracing-opentelemetry can be used to export and visualize tracing span data.
- opentelemetry-remote-context: Demonstrates how tracing-opentelemetry can be used to extract and inject remote context when traces span multiple systems.