Hello World

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

.github/workflows/build.yml

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+name: Sanity Check codebase
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    name: Build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: [stable, beta, nightly]
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.node }}
+          override: true
+
+      - name: Run cargo check
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+
+      - name: Run cargo test
+        run: make check
+
+  lints:
+    name: Lints
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v2
+
+      - name: Install stable toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+          components: rustfmt, clippy
+
+      - name: Run cargo fmt
+        uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check

Cargo.toml

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+[package]
+name = "opentelemetry-common"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+opentelemetry = { version = "0.25", features = ["logs"] }
+opentelemetry-appender-log = { version = "0.25", default-features = false }
+opentelemetry_sdk = { version = "0.25", features = [ "logs", "rt-tokio" ] }
+opentelemetry-otlp = { version = "0.25", features = [ "http-proto", "reqwest-client", "reqwest-rustls", "logs" ] }
+opentelemetry-semantic-conventions = { version = "0.25.0"  }
+anyhow = "^1"
+log = { version = "0.4", features = ["std"] }
+
+[dev-dependencies]
+clap = { version = "4.0.26", features = ["derive"] }
+tokio = { version = "^1.29.1", features = ["rt-multi-thread", "parking_lot"] }
+env_logger = "0.11.3"

examples/main.rs

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+use clap::Parser;
+
+use opentelemetry_common::Opentelemetry;
+
+#[derive(Debug, Parser)]
+#[clap(name = "opentelemetry.rs")]
+pub struct Args {
+    #[clap(short, long, value_parser)]
+    pub url: String,
+    #[clap(short, long, value_parser)]
+    pub message: String,
+    #[clap(short, long)]
+    pub level: String,
+}
+
+#[macro_export]
+macro_rules! async_run {
+    ($rt:expr, $expr:expr) => {{
+        $rt.block_on($expr)
+    }};
+    ($expr:expr) => {{
+        let rt = tokio::runtime::Runtime::new().unwrap();
+        $crate::async_run!(rt, $expr)
+    }};
+}
+
+// the async main is not required by our application
+// but the opentelemetry app is requiring to be
+// in an async context, so we use this
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let args = Args::parse();
+    let url = args.url;
+
+    let mut manager = Opentelemetry::new();
+    manager.init_log("example", &args.level, &url)?;
+
+    match args.level.as_str() {
+        "info" => log::info!("{}", args.message),
+        "debug" => log::debug!("{}", args.message),
+        _ => anyhow::bail!("level `{}` not found", args.level),
+    }
+    Ok(())
+}

src/lib.rs

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+pub mod log;
+pub use anyhow;
+
+use std::sync::Arc;
+
+use opentelemetry::global;
+use opentelemetry_sdk::logs as sdklogs;
+
+#[derive(Debug, Clone)]
+pub struct Opentelemetry {
+    pub(crate) logger: Option<Arc<sdklogs::LoggerProvider>>,
+}
+
+impl Default for Opentelemetry {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Opentelemetry {
+    pub fn new() -> Self {
+        Opentelemetry { logger: None }
+    }
+
+    pub fn init_log(
+        &mut self,
+        tag: &str,
+        level: &str,
+        exporter_endpoint: &str,
+    ) -> anyhow::Result<()> {
+        log::init(self, tag.to_owned(), level, exporter_endpoint)?;
+        Ok(())
+    }
+}
+
+impl Drop for Opentelemetry {
+    fn drop(&mut self) {
+        let Some(Err(err)) = self.logger.as_ref().map(|log| log.shutdown()) else {
+            return;
+        };
+        panic!("Failed to shutdown logger: {:?}", err);
+    }
+}

src/log.rs

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+//! Logging module.
+use std::str::FromStr;
+use std::sync::Arc;
+
+use opentelemetry::KeyValue;
+use opentelemetry_appender_log::OpenTelemetryLogBridge;
+use opentelemetry_otlp::HttpExporterBuilder;
+use opentelemetry_otlp::Protocol;
+use opentelemetry_otlp::WithExportConfig;
+use opentelemetry_sdk::Resource;
+
+use crate::Opentelemetry;
+
+/// Initialize a new logger exported with open telemetry.
+pub fn init(
+    manager: &mut Opentelemetry,
+    tag: String,
+    level: &str,
+    exporter_endpoint: &str,
+) -> anyhow::Result<()> {
+    let logger_provider = opentelemetry_otlp::new_pipeline()
+        .logging()
+        .with_resource(Resource::new(vec![KeyValue::new(
+            opentelemetry_semantic_conventions::resource::SERVICE_NAME,
+            tag,
+        )]))
+        .with_exporter(
+            http_exporter()
+                .with_protocol(Protocol::HttpBinary) //can be changed to `Protocol::HttpJson` to export in JSON format
+                .with_endpoint(format!("{exporter_endpoint}/v1/logs")),
+        )
+        .install_batch(opentelemetry_sdk::runtime::Tokio)?;
+    manager.logger = Some(Arc::new(logger_provider.clone()));
+
+    // Setup Log Appender for the log crate.
+    let otel_log_appender = OpenTelemetryLogBridge::new(&logger_provider);
+
+    // the install method set a global provider, that we can use now
+    log::set_boxed_logger(Box::new(otel_log_appender)).map_err(|err| anyhow::anyhow!("{err}"))?;
+    let level = log::Level::from_str(level)?;
+    log::set_max_level(level.to_level_filter());
+    Ok(())
+}
+
+fn http_exporter() -> HttpExporterBuilder {
+    opentelemetry_otlp::new_exporter().http()
+}