Move metrics logic inside of heroku/ruby

Cargo.toml

@@ -1,10 +1,5 @@
 [workspace]
-resolver = "2"
-members = [
- "buildpacks/metrics-agent",
- "buildpacks/ruby",
- "commons"
-]
+members = ["buildpacks/ruby", "commons"]
 
 [workspace.package]
 rust-version = "1.64"

buildpacks/ruby/Cargo.toml

@@ -23,6 +23,7 @@ tempfile = "3"
 thiserror = "1"
 ureq = "2"
 url = "2"
+clap = { version = "4.4.1", features = ["derive"] }
 
 [dev-dependencies]
 libcnb-test = "=0.14.0"

buildpacks/metrics-agent/src/bin/agentmon_loop.rs → buildpacks/ruby/src/bin/agentmon_loop.rs

@@ -20,7 +20,9 @@ const SLEEP_FOR: Duration = Duration::from_secs(1);
 ///
 /// Example:
 ///
+/// ```shell
 /// $ cargo run --bin agentmon_loop -- --path <path/to/agentmon/binary>
+/// ```
 
 /// Turn CLI arguments into a Rust struct
 #[derive(Parser, Debug)]
@@ -37,7 +39,7 @@ fn main() {
  exit(1);
  }
 
- let agentmon_args = match build_args(std::env::vars().collect::<HashMap<String, String>>()) {
+ let agentmon_args = match build_args(&std::env::vars().collect::<HashMap<String, String>>()) {
  Ok(args) => args,
  Err(e) => {
  eprintln!("Cannot start agentmon: {e}");
@@ -90,22 +92,21 @@ enum Error {
 ///
 /// # Errors
 ///
-/// - PORT is not set
-/// - HEROKU_METRICS_URL is not set
-/// - DYNO starts with `run.`
-fn build_args(env: HashMap<String, String>) -> Result<Vec<String>, Error> {
+/// - Environment variables: PORT or `HEROKU_METRICS_URL` are not set
+/// - Environment variable DYNO starts with `run.`
+fn build_args(env: &HashMap<String, String>) -> Result<Vec<String>, Error> {
  let mut args = Vec::new();
- if let Some(true) = env.get("DYNO").map(|value| value.starts_with("run.")) {
+ if env.get("DYNO").is_some_and(|value| value.starts_with("run.")) {
  return Err(Error::RunDynoDetected);
  }
 
  if let Some(port) = env.get("PORT") {
- args.push(format!("statsd-addr=:{port}"));
+ args.push(format!("-statsd-addr=:{port}"));
  } else {
  return Err(Error::MissingPort);
  };
 
- if let Some(true) = env.get("AGENTMON_DEBUG").map(|value| value == "true") {
+ if env.get("AGENTMON_DEBUG").is_some_and(|value| value == "true") {
  args.push("-debug".to_string());
  };
 
@@ -124,7 +125,7 @@ mod test {
 
  #[test]
  fn missing_port() {
- let result = build_args(HashMap::new());
+ let result = build_args(&HashMap::new());
 
  assert_eq!(result, Err(Error::MissingPort));
  }
@@ -138,12 +139,12 @@ mod test {
  "https://example.com".to_string(),
  );
 
- let result = build_args(env);
+ let result = build_args(&env);
 
  assert_eq!(
  result,
  Ok(vec![
- "statsd-addr=:90210".to_string(),
+ "-statsd-addr=:90210".to_string(),
  "https://example.com".to_string()
  ])
  );
@@ -159,12 +160,12 @@ mod test {
  );
  env.insert("AGENTMON_DEBUG".to_string(), "true".to_string());
 
- let result = build_args(env);
+ let result = build_args(&env);
 
  assert_eq!(
  result,
  Ok(vec![
- "statsd-addr=:90210".to_string(),
+ "-statsd-addr=:90210".to_string(),
  "-debug".to_string(),
  "https://example.com".to_string()
  ])

buildpacks/ruby/src/bin/launch_daemon.rs

@@ -0,0 +1,77 @@
+use clap::Parser;
+use std::path::PathBuf;
+use std::process::exit;
+use std::process::Command;
+
+/// Schedules agentmon to run as a background daemon
+
+/// CLI argument parser
+///
+/// ```shell
+/// $ cargo run --bin launch_daemon \
+/// --log <path/to/log.txt> \
+/// --agentmon <path/to/agentmon>
+/// --loop-path <path/to/agentmon_loop>
+/// ```
+#[derive(Parser, Debug)]
+struct Args {
+ #[arg(long, value_parser = absolute_path_exists)]
+ log: PathBuf,
+
+ #[arg(long, value_parser = absolute_path_exists)]
+ agentmon: PathBuf,
+
+ #[arg(long, value_parser = absolute_path_exists)]
+ loop_path: PathBuf,
+}
+
+fn absolute_path_exists(s: &str) -> Result<PathBuf, String> {
+ fs_err::canonicalize(PathBuf::from(s))
+ .map_err(|e| format!("{s} is not a valid path. Details: {e}"))
+ .and_then(|path| match path.try_exists() {
+ Ok(true) => Ok(path),
+ Ok(false) => Err(format!("path {} does not exist", path.display())),
+ Err(e) => Err(format!("problem verifying {} exists {e}", path.display())),
+ })
+}
+
+fn main() {
+ let Args {
+ log,
+ loop_path,
+ agentmon,
+ } = Args::parse();
+
+ let mut command = Command::new("start-stop-daemon");
+ if std::env::var_os("AGENTMON_DEBUG").is_some() {
+ command.args(["--output", &log.to_string_lossy()]);
+ } else {
+ match fs_err::write(&log, "To enable logging run with AGENTMON_DEBUG=1") {
+ Ok(_) => {}
+ Err(error) => eprintln!(
+ "Could not write to log file {}. Reason: {error}",
+ log.display()
+ ),
+ };
+ }
+ command.args([
+ "--start",
+ "--background",
+ "--exec",
+ &loop_path.to_string_lossy(),
+ "--",
+ "--path",
+ &agentmon.to_string_lossy(),
+ ]);
+
+ match command.spawn().map(|mut child| child.wait()) {
+ Ok(_) => {}
+ Err(error) => {
+ eprintln!(
+ "Command failed {}. Details: {error}",
+ commons::fun_run::display(&mut command)
+ );
+ exit(1)
+ }
+ };
+}

buildpacks/ruby/src/layers.rs

@@ -1,5 +1,6 @@
 mod bundle_download_layer;
 mod bundle_install_layer;
+pub(crate) mod metrics_agent_install;
 mod ruby_install_layer;
 
 pub(crate) use self::bundle_download_layer::BundleDownloadLayer;