Add more logging to `rust-dataflow` example

Cargo.lock

@@ -1009,6 +1009,8 @@ dependencies = [
  "eyre",
  "serde_yaml 0.8.23",
  "tokio",
+ "tracing",
+ "tracing-subscriber",
  "uuid 1.2.1",
 ]
 

Cargo.toml

@@ -32,6 +32,8 @@ dora-core = { path = "libraries/core" }
 dunce = "1.0.2"
 serde_yaml = "0.8.23"
 uuid = { version = "1.2.1", features = ["v4", "serde"] }
+tracing = "0.1.36"
+tracing-subscriber = "0.3.15"
 
 [[example]]
 name = "c-dataflow"

binaries/daemon/src/lib.rs

@@ -414,6 +414,9 @@ impl Daemon {
                     if let Some(exit_when_done) = &mut self.exit_when_done {
                         exit_when_done.remove(&dataflow_id);
                         if exit_when_done.is_empty() {
+                            tracing::info!(
+                                "exiting daemon because all required dataflows are finished"
+                            );
                             return Ok(RunStatus::Exit);
                         }
                     }

examples/rust-dataflow/run.rs

@@ -9,6 +9,8 @@ use uuid::Uuid;
 
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
+    set_up_tracing().wrap_err("failed to set up tracing subscriber")?;
+
     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")?;
@@ -69,3 +71,12 @@ pub async fn read_descriptor(file: &Path) -> eyre::Result<Descriptor> {
         serde_yaml::from_slice(&descriptor_file).context("failed to parse given descriptor")?;
     Ok(descriptor)
 }
+
+fn set_up_tracing() -> eyre::Result<()> {
+    use tracing_subscriber::prelude::__tracing_subscriber_SubscriberExt;
+
+    let stdout_log = tracing_subscriber::fmt::layer().pretty();
+    let subscriber = tracing_subscriber::Registry::default().with(stdout_log);
+    tracing::subscriber::set_global_default(subscriber)
+        .context("failed to set tracing global subscriber")
+}