Simplify the `run.rs` script of the `rust-dataflow` example using `xshell`

The `xshell` crate provides a more convenient way to build and run a `Command`, which is more similar to traditional bash scripts. Using this crate, we can simplify our `run.rs` script while still being platform-independent and not requiring any external dependencies. We can also still run the examples using `cargo run --example`.

Cargo.lock

@@ -2368,6 +2368,7 @@ dependencies = [
  "tokio-stream",
  "tracing",
  "uuid",
+ "xshell",
 ]
 
 [[package]]

Cargo.toml

@@ -97,6 +97,7 @@ uuid = { version = "1.7", features = ["v7", "serde"] }
 tracing = "0.1.36"
 futures = "0.3.25"
 tokio-stream = "0.1.11"
+xshell = "0.2.6"
 
 [[example]]
 name = "c-dataflow"

examples/rust-dataflow/run.rs

@@ -1,46 +1,53 @@
-use dora_tracing::set_up_tracing;
-use eyre::{bail, Context};
-use std::path::Path;
+use eyre::ContextCompat;
+use std::path::{Path, PathBuf};
+use xshell::{cmd, Shell};
 
-#[tokio::main]
-async fn main() -> eyre::Result<()> {
-    set_up_tracing("rust-dataflow-runner").wrap_err("failed to set up tracing subscriber")?;
+fn main() -> eyre::Result<()> {
+    // create a new shell in this folder
+    let sh = prepare_shell()?;
+    // build the `dora` binary (you can skip this if you use `cargo install dora-cli`)
+    let dora = prepare_dora(&sh)?;
 
-    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")?;
+    // build the dataflow using `dora build`
+    cmd!(sh, "{dora} build dataflow.yml").run()?;
+
+    // start up the dora daemon and coordinator
+    cmd!(sh, "{dora} up").run()?;
 
-    let dataflow = Path::new("dataflow.yml");
-    build_dataflow(dataflow).await?;
+    // start running the dataflow.yml -> outputs the UUID assigned to the dataflow
+    let output = cmd!(sh, "{dora} start dataflow.yml --attach").read_stderr()?;
+    let uuid = output.lines().next().context("no output")?;
 
-    run_dataflow(dataflow).await?;
+    // stop the dora daemon and coordinator again
+    cmd!(sh, "{dora} destroy").run()?;
+
+    // verify that the node output was written to `out`
+    sh.change_dir("out");
+    sh.change_dir(uuid);
+    let sink_output = sh.read_file("log_rust-sink.txt")?;
+    if sink_output.lines().count() < 50 {
+        eyre::bail!("sink did not receive the expected number of messages")
+    }
 
     Ok(())
 }
 
-async fn build_dataflow(dataflow: &Path) -> eyre::Result<()> {
-    let cargo = std::env::var("CARGO").unwrap();
-    let mut cmd = tokio::process::Command::new(&cargo);
-    cmd.arg("run");
-    cmd.arg("--package").arg("dora-cli");
-    cmd.arg("--").arg("build").arg(dataflow);
-    if !cmd.status().await?.success() {
-        bail!("failed to build dataflow");
-    };
-    Ok(())
+/// Prepares a shell and set the working directory to the parent folder of this file.
+///
+/// You can use your system shell instead (e.g. `bash`);
+fn prepare_shell() -> Result<Shell, eyre::Error> {
+    let sh = Shell::new()?;
+    let root = Path::new(env!("CARGO_MANIFEST_DIR"));
+    sh.change_dir(root.join(file!()).parent().unwrap());
+    Ok(sh)
 }
 
-async fn run_dataflow(dataflow: &Path) -> eyre::Result<()> {
-    let cargo = std::env::var("CARGO").unwrap();
-    let mut cmd = tokio::process::Command::new(&cargo);
-    cmd.arg("run");
-    cmd.arg("--package").arg("dora-cli");
-    cmd.arg("--")
-        .arg("daemon")
-        .arg("--run-dataflow")
-        .arg(dataflow);
-    if !cmd.status().await?.success() {
-        bail!("failed to run dataflow");
-    };
-    Ok(())
+/// Build the `dora` command-line executable from this repo.
+///
+/// You can skip this step and run `cargo install dora-cli --locked` instead.
+fn prepare_dora(sh: &Shell) -> eyre::Result<PathBuf> {
+    cmd!(sh, "cargo build --package dora-cli").run()?;
+    let root = Path::new(env!("CARGO_MANIFEST_DIR"));
+    let dora = root.join("target").join("debug").join("dora");
+    Ok(dora)
 }