make rustfmt optional

tonic-build/Cargo.toml

@@ -11,4 +11,7 @@ prost-build = "0.5"
 syn = "1.0"
 quote = "1.0"
 proc-macro2 = "1.0"
-rustfmt = "0.10"
+
+
+[features]
+rustfmt = []

tonic-build/src/lib.rs

@@ -28,6 +28,7 @@ where
     compile_protos_with_out_dir(protos, includes, package, out_dir.as_str())
 }
 
+#[allow(unused_variables)]
 pub fn compile_protos_with_out_dir<P: AsRef<Path>>(
     protos: &[P],
     includes: &[P],
@@ -40,6 +41,7 @@ pub fn compile_protos_with_out_dir<P: AsRef<Path>>(
     config.out_dir(out_dir.as_ref());
     config.compile_protos(protos, includes)?;
 
+    #[cfg(feature = "rustfmt")]
     fmt(
         out_dir.as_ref().to_str().expect("Execpted utf8 out_dir"),
         &format!("{}.rs", package),
@@ -48,6 +50,7 @@ pub fn compile_protos_with_out_dir<P: AsRef<Path>>(
     Ok(())
 }
 
+#[cfg(feature = "rustfmt")]
 fn fmt(out_dir: &str, file: &str) {
     let out = Command::new("rustfmt")
         .arg("--emit")

tonic-examples/Cargo.toml

@@ -33,4 +33,4 @@ async-stream = { git = "https://github.com/tokio-rs/async-stream" }
 http = "0.1"
 
 [build-dependencies]
-tonic-build = { path = "../tonic-build" }
+tonic-build = { path = "../tonic-build", features = ["rustfmt"] }