allow including extra info in `--version` output

Cargo.toml

@@ -102,7 +102,7 @@ thread_local = "1.1.7"
 hmac = "0.12.1"
 sha-1 = "0.10.1"
 # used for conduit's CLI and admin room command parsing
-clap = { version = "4.3.0", default-features = false, features = ["std", "derive", "help", "usage", "error-context"] }
+clap = { version = "4.3.0", default-features = false, features = ["std", "derive", "help", "usage", "error-context", "string"] }
 futures-util = { version = "0.3.28", default-features = false }
 # Used for reading the configuration from conduit.toml & environment variables
 figment = { version = "0.10.8", features = ["env", "toml"] }

flake.nix

@@ -73,6 +73,7 @@
       });
 
       env = pkgs: {
+        CONDUIT_VERSION_EXTRA = self.shortRev or self.dirtyShortRev;
         ROCKSDB_INCLUDE_DIR = "${rocksdb' pkgs}/include";
         ROCKSDB_LIB_DIR = "${rocksdb' pkgs}/lib";
       }

src/clap.rs

@@ -2,9 +2,23 @@
 
 use clap::Parser;
 
+/// Returns the current version of the crate with extra info if supplied
+///
+/// Set the environment variable `CONDUIT_VERSION_EXTRA` to any UTF-8 string to
+/// include it in parenthesis after the SemVer version. A common value are git
+/// commit hashes.
+fn version() -> String {
+    let cargo_pkg_version = env!("CARGO_PKG_VERSION");
+
+    match option_env!("CONDUIT_VERSION_EXTRA") {
+        Some(x) => format!("{} ({})", cargo_pkg_version, x),
+        None => cargo_pkg_version.to_owned(),
+    }
+}
+
 /// Command line arguments
 #[derive(Parser)]
-#[clap(about, version)]
+#[clap(about, version = version())]
 pub struct Args {}
 
 /// Parse command line arguments into structured data