move healthcheck to a separate binary

Author: randomairborne

Cargo.lock

@@ -19,9 +19,10 @@ FROM scratch
 WORKDIR /
 
 COPY --from=server-builder /build/target/release/mcping /usr/bin/mcping
+COPY --from=server-builder /build/target/release/mcping-healthcheck /usr/bin/mcping-healthcheck
 COPY --from=client-builder /assets/ /var/www/mcping/
 
 ENV ASSET_DIR="/var/www/mcping/"
 
-HEALTHCHECK --interval=5s --timeout=5s --retries=5 CMD ["/usr/bin/mcping", "healthcheck", "http://127.0.0.1:8080"]
+HEALTHCHECK --interval=5s --timeout=5s --retries=5 CMD ["/usr/bin/mcping-healthcheck", "http://127.0.0.1:8080"]
 ENTRYPOINT ["/usr/bin/mcping"]

Dockerfile

@@ -0,0 +1,12 @@
+#[tokio::main(flavor = "current_thread")]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let Some(url) = std::env::args().nth(1) else {
+        return Err("`mcping-healthcheck` requires exactly one argument.".into());
+    };
+    if std::env::args().len() != 2 {
+        return Err("`mcping-healthcheck` requires exactly one argument.".into());
+    }
+    reqwest::get(url).await?.error_for_status()?;
+    println!("Health check succeeded");
+    Ok(())
+}

src/bin/mcping-healthcheck.rs

@@ -59,9 +59,6 @@ static JSON_CONTENT_TYPE: HeaderValue = HeaderValue::from_static("application/js
 #[allow(clippy::too_many_lines)]
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    if let Some(subcmd) = std::env::args().nth(1).as_deref() {
-        return check_health(subcmd).await;
-    }
     tracing_subscriber::fmt()
         .with_max_level(Level::TRACE)
         .json()
@@ -193,21 +190,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     Ok(())
 }
 
-async fn check_health(subcmd: &str) -> Result<(), Box<dyn std::error::Error>> {
-    if subcmd != "healthcheck" {
-        return Err("The only valid subcommand is `healthcheck`".into());
-    }
-    let Some(url) = std::env::args().nth(2) else {
-        return Err("`healthcheck` requires exactly one argument.".into());
-    };
-    if std::env::args().len() != 3 {
-        return Err("`healthcheck` requires exactly one argument.".into());
-    }
-    reqwest::get(url).await?.error_for_status()?;
-    println!("Health check succeeded");
-    Ok(())
-}
-
 fn get_csp() -> ContentSecurityPolicy {
     ContentSecurityPolicy::new_empty()
         .upgrade_insecure_requests(true)