feat: add COMMIT_HASH build time env var

build.rs

@@ -0,0 +1,17 @@
+use std::process::Command;
+
+fn main() {
+    let commit_hash = match std::env::var("COMMIT_HASH") {
+        Ok(commit_hash_string) => commit_hash_string,
+        Err(_) => {
+            match Command::new("git")
+                .args(vec!["rev-parse", "--short", "HEAD"])
+                .output()
+            {
+                Ok(x) => String::from_utf8_lossy(x.stdout.trim_ascii_end()).into_owned(),
+                Err(_) => "no hash :(".to_string(),
+            }
+        }
+    };
+    println!("cargo::rustc-env=COMMIT_HASH=\"{}\"", commit_hash);
+}

flake.nix

@@ -44,6 +44,9 @@
 
           # Additional environment variables can be set directly
           # MY_CUSTOM_VAR = "some value";
+          COMMIT_HASH = builtins.substring 0 7 (
+            if self ? rev then self.rev else "nixDirt"
+          );
         };
 
         craneLibLLvmTools = craneLib.overrideToolchain

src/main.rs

@@ -14,6 +14,8 @@ async fn main() {
     tracing_subscriber::fmt::init();
     let cache = KubeCache::Cache::create().unwrap();
     let arcCache = Arc::new(cache);
+    let commit_hash: &'static str = env!("COMMIT_HASH");
+    println!("COMMIT_HASH: {}", commit_hash);
 
     let mut listener = TcpListener::bind("0.0.0.0:25565").await.unwrap();