### Install cargo-insta

Source: https://github.com/fast/fastrace/blob/main/CONTRIBUTING.md

Command to install the cargo-insta tool for snapshot testing.

```bash
cargo install cargo-insta
```

--------------------------------

### Setup OpenTelemetry Collector

Source: https://github.com/fast/fastrace/blob/main/crates/fastrace-opentelemetry/README.md

Start the OpenTelemetry Collector using Docker Compose to receive traces from Jaeger and Zipkin.

```shell
docker compose -f dev/docker-compose.yaml up
```

--------------------------------

### Run Synchronous Example

Source: https://github.com/fast/fastrace/blob/main/crates/fastrace-opentelemetry/README.md

Execute the synchronous example provided by Fastrace to test trace reporting.

```shell
cargo run --example synchronous
```

--------------------------------

### Install Dependencies and Benchmark Fastrace

Source: https://github.com/fast/fastrace/blob/main/benches/results/README.md

Installs necessary system packages, Rust, and the cargo-criterion tool. Clones the Fastrace repository and runs the comparison benchmark, saving the output to a file.

```shell
sudo apt update
sudo apt install build-essential libssl-dev pkg-config -y
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source $HOME/.cargo/env
cargo install --version=1.0.0-alpha3 cargo-criterion
git clone https://github.com/fast/fastrace.git
cd fastrace
cargo criterion compare --message-format=json | grep "benchmark-complete" > compare-xxx.txt
```

--------------------------------

### Create a Root Span and Local Context

Source: https://github.com/fast/fastrace/blob/main/README.md

Use `Span::root` to start a new trace with a randomly generated context and `Span::set_local_parent` to establish a local tracing context for the current thread. The `func_path!()` macro automatically captures the current function's name for the root span.

```rust
use fastrace::prelude::*;

pub fn send_request(req: HttpRequest) -> Result<(), Error> {
    let root = Span::root(func_path!(), SpanContext::random());
    let _guard = root.set_local_parent();

    // ...
}
```

--------------------------------

### Initialize OpenTelemetry Reporter

Source: https://github.com/fast/fastrace/blob/main/crates/fastrace-opentelemetry/README.md

Configure and initialize the OpenTelemetryReporter with an OTLP exporter endpoint and resource attributes. This reporter is then set as the global reporter for Fastrace.

```rust
use std::borrow::Cow;

use fastrace::collector::Config;
use fastrace::prelude::*;
use fastrace_opentelemetry::OpenTelemetryReporter;
use opentelemetry::InstrumentationScope;
use opentelemetry::KeyValue;
use opentelemetry_otlp::SpanExporter;
use opentelemetry_otlp::WithExportConfig;
use opentelemetry_sdk::Resource;

// Initialize reporter
let reporter = OpenTelemetryReporter::new(
    SpanExporter::builder()
        .with_tonic()
        .with_endpoint("http://127.0.0.1:4317".to_string())
        .with_protocol(opentelemetry_otlp::Protocol::Grpc)
        .with_timeout(opentelemetry_otlp::OTEL_EXPORTER_OTLP_TIMEOUT_DEFAULT)
        .build()
        .expect("initialize otlp exporter"),
    Cow::Owned(
        Resource::builder()
            .with_attributes([KeyValue::new("service.name", "asynchronous")])
            .build()
    ),
    InstrumentationScope::builder("example-crate").with_version(env!("CARGO_PKG_VERSION")).build(),
);
fastrace::set_reporter(reporter, Config::default());

{
    // Start tracing
    let root = Span::root("root", SpanContext::random());
}

fastrace::flush();
```

--------------------------------

### Add Fastrace and OpenTelemetry Dependencies

Source: https://github.com/fast/fastrace/blob/main/crates/fastrace-opentelemetry/README.md

Include the necessary dependencies in your Cargo.toml file to use Fastrace and its OpenTelemetry reporter.

```toml
[dependencies]
fastrace = { version = "0.7", features = ["enable"] }
fastrace-opentelemetry = "0.18"
```

--------------------------------

### Configure Async OpenTelemetry Exporter with Tokio

Source: https://github.com/fast/fastrace/blob/main/crates/fastrace-opentelemetry/README.md

Adapt the OpenTelemetryReporter to use an async exporter, such as OTLP HTTP with reqwest, by providing a Tokio runtime handle for blocking operations.

```rust
let handle = tokio::runtime::Handle::current();

let reporter = OpenTelemetryReporter::new(exporter, resource, instrumentation_scope)
    .with_block_on(move |future| handle.block_on(future));
```

--------------------------------

### Common Cargo Commands

Source: https://github.com/fast/fastrace/blob/main/CONTRIBUTING.md

Standard commands for analyzing, building, linting, and testing the Rust project.

```bash
cargo check
```

```bash
cargo build
```

```bash
cargo clippy
```

```bash
cargo test
```

```bash
cargo bench
```

--------------------------------

### Initialize Reporter and Collect Spans

Source: https://github.com/fast/fastrace/blob/main/README.md

Initialize a ConsoleReporter early in your application and ensure flush() is called before termination. Root spans are recommended for short tasks to ensure traces are reported.

```rust
use fastrace::collector::Config;
use fastrace::collector::ConsoleReporter;
use fastrace::prelude::*;

fn main() {
    fastrace::set_reporter(ConsoleReporter, Config::default());

    loop {
        let root = Span::root("worker-loop", SpanContext::random());
        let _guard = root.set_local_parent();

        handle_request();
    }

    fastrace::flush();
}
```

--------------------------------

### Add Fastrace Dependency

Source: https://github.com/fast/fastrace/blob/main/README.md

Include fastrace as a dependency in your Cargo.toml file with the 'enable' feature.

```toml
[dependencies]
fastrace = { version = "0.7", features = ["enable"] }
```

--------------------------------

### Add Fastrace Dependency to Cargo.toml

Source: https://github.com/fast/fastrace/blob/main/README.md

Include `fastrace` as a dependency in your library's `Cargo.toml` file. No extra features are required for basic integration.

```toml
[dependencies]
fastrace = "0.7"
```

--------------------------------

### Run All Targets/Workspace

Source: https://github.com/fast/fastrace/blob/main/CONTRIBUTING.md

Execute cargo commands across all targets and the entire workspace.

```bash
cargo <cmd> --all-targets --workspace
```

--------------------------------

### Migrate from tokio-tracing to Fastrace

Source: https://github.com/fast/fastrace/blob/main/README.md

Use this snippet to capture spans from libraries instrumented with tokio-tracing when migrating to fastrace. It requires the fastrace-tracing crate.

```rust
let subscriber = tracing_subscriber::Registry::default().with(fastrace_tracing::FastraceCompatLayer::new());
tracing::subscriber::set_global_default(subscriber).unwrap();
```

--------------------------------

### Bridge Fastrace Span to OpenTelemetry Context

Source: https://github.com/fast/fastrace/blob/main/crates/fastrace-opentelemetry/README.md

Activate the current Fastrace local parent span as an OpenTelemetry context. This is useful when integrating with libraries that rely on OpenTelemetry's `Context::current()`.

```rust
use fastrace::prelude::*;
use fastrace_opentelemetry::current_opentelemetry_context;
use opentelemetry::trace::TraceContextExt;
use opentelemetry::Context;

fn main() {
    let span = Span::root("root", SpanContext::random());
    let _guard = span.set_local_parent();

    let _otel_guard = current_opentelemetry_context()
        .map(|cx| Context::current().with_remote_span_context(cx).attach());

    // Call library code that uses `Context::current()`.
}
```

--------------------------------

### Trace a Function with #[fastrace::trace]

Source: https://github.com/fast/fastrace/blob/main/README.md

Apply the `#[fastrace::trace]` attribute to a function to automatically collect `SpanRecord` data when the function is called within an active tracing context.

```rust
#[fastrace::trace]
pub fn send_request(req: HttpRequest) -> Result<(), Error> {
    // ...
}
```

--------------------------------

### Test Specific Function

Source: https://github.com/fast/fastrace/blob/main/CONTRIBUTING.md

Run cargo tests targeting a specific function or test name.

```bash
cargo test multiple_local_parent
```

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