Enable tracing for C, C++, and `rust-dataflow-url` examples

examples/c++-dataflow/run.rs

@@ -4,11 +4,17 @@ use std::{
     ffi::{OsStr, OsString},
     path::Path,
 };
+use tracing::metadata::LevelFilter;
+use tracing_subscriber::Layer;
 
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
+    set_up_tracing().wrap_err("failed to set up tracing")?;
+
     if cfg!(windows) {
-        eprintln!("The c++ example does not work on Windows currently because of a linker error");
+        tracing::error!(
+            "The c++ example does not work on Windows currently because of a linker error"
+        );
         return Ok(());
     }
 
@@ -275,3 +281,14 @@ pub fn library_filename<S: AsRef<OsStr>>(name: S) -> OsString {
     string.push(DLL_SUFFIX);
     string
 }
+
+fn set_up_tracing() -> eyre::Result<()> {
+    use tracing_subscriber::prelude::__tracing_subscriber_SubscriberExt;
+
+    let stdout_log = tracing_subscriber::fmt::layer()
+        .pretty()
+        .with_filter(LevelFilter::DEBUG);
+    let subscriber = tracing_subscriber::Registry::default().with(stdout_log);
+    tracing::subscriber::set_global_default(subscriber)
+        .context("failed to set tracing global subscriber")
+}

examples/c-dataflow/run.rs

@@ -4,9 +4,13 @@ use std::{
     ffi::{OsStr, OsString},
     path::Path,
 };
+use tracing::metadata::LevelFilter;
+use tracing_subscriber::Layer;
 
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
+    set_up_tracing().wrap_err("failed to set up tracing")?;
+
     let root = Path::new(env!("CARGO_MANIFEST_DIR"));
     std::env::set_current_dir(root.join(file!()).parent().unwrap())
         .wrap_err("failed to set working dir")?;
@@ -134,3 +138,14 @@ pub fn library_filename<S: AsRef<OsStr>>(name: S) -> OsString {
     string.push(DLL_SUFFIX);
     string
 }
+
+fn set_up_tracing() -> eyre::Result<()> {
+    use tracing_subscriber::prelude::__tracing_subscriber_SubscriberExt;
+
+    let stdout_log = tracing_subscriber::fmt::layer()
+        .pretty()
+        .with_filter(LevelFilter::DEBUG);
+    let subscriber = tracing_subscriber::Registry::default().with(stdout_log);
+    tracing::subscriber::set_global_default(subscriber)
+        .context("failed to set tracing global subscriber")
+}

examples/rust-dataflow-url/run.rs

@@ -1,8 +1,12 @@
 use eyre::{bail, Context};
 use std::path::Path;
+use tracing::metadata::LevelFilter;
+use tracing_subscriber::Layer;
 
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
+    set_up_tracing().wrap_err("failed to set up tracing")?;
+
     let root = Path::new(env!("CARGO_MANIFEST_DIR"));
     std::env::set_current_dir(root.join(file!()).parent().unwrap())
         .wrap_err("failed to set working dir")?;
@@ -37,3 +41,14 @@ async fn build_package(package: &str) -> eyre::Result<()> {
     };
     Ok(())
 }
+
+fn set_up_tracing() -> eyre::Result<()> {
+    use tracing_subscriber::prelude::__tracing_subscriber_SubscriberExt;
+
+    let stdout_log = tracing_subscriber::fmt::layer()
+        .pretty()
+        .with_filter(LevelFilter::DEBUG);
+    let subscriber = tracing_subscriber::Registry::default().with(stdout_log);
+    tracing::subscriber::set_global_default(subscriber)
+        .context("failed to set tracing global subscriber")
+}