Move starting of tasks into a helper struct

tests/common/mod.rs

@@ -5,3 +5,4 @@ pub mod osm;
 pub mod osm_db;
 pub mod osrm_world;
 pub mod scenario_id;
+pub mod task_starter;

tests/common/task_starter.rs

@@ -0,0 +1,65 @@
+use std::{
+    io::{BufRead, BufReader},
+    process::{Child, Command, Stdio},
+};
+
+#[derive(Default)]
+pub struct TaskStarter {
+    ready: bool,
+    command: String,
+    arguments: Vec<String>,
+    child: Option<Child>,
+}
+
+impl TaskStarter {
+    pub fn new(command: &str) -> Self {
+        Self {
+            ready: false,
+            command: command.into(),
+            arguments: Vec::new(),
+            child: None,
+        }
+    }
+    pub fn is_ready(&self) -> bool {
+        self.ready
+    }
+    pub fn arg(&mut self, argument: &str) -> &mut Self {
+        self.arguments.push(argument.into());
+        self
+    }
+
+    pub fn spawn_wait_till_ready(&mut self, ready_token: &str) {
+        // TODO: move the child handling into a convenience struct
+
+        let mut command = &mut Command::new(&self.command);
+        for argument in &self.arguments {
+            command = command.arg(argument);
+        }
+
+        match command.stdout(Stdio::piped()).spawn() {
+            Ok(o) => self.child = Some(o),
+            Err(e) => panic!("cannot spawn task: {e}"),
+        }
+
+        if let Some(output) = &mut self.child.as_mut().unwrap().stdout {
+            // implement with a timeout
+            let mut reader = BufReader::new(output);
+            let mut line = String::new();
+            while let Ok(_count) = reader.read_line(&mut line) {
+                // println!("count: {count} ->{line}");
+                if line.contains(ready_token) {
+                    self.ready = true;
+                    break;
+                }
+            }
+        }
+    }
+}
+
+impl Drop for TaskStarter {
+    fn drop(&mut self) {
+        if let Err(e) = self.child.as_mut().expect("can't access child").kill() {
+            panic!("shutdown failed: {e}");
+        }
+    }
+}