only install extra dep if feature is on, update examples to take command entirely

Author: humbertoyusta

crates/rmcp/Cargo.toml

@@ -18,7 +18,6 @@ serde_json = "1.0"
 thiserror = "2"
 chrono = { version = "0.4.38", features = ["serde"] }
 tokio = { version = "1", features = ["sync", "macros", "rt", "time"] }
-process-wrap = { version = "8.2", features = ["tokio1"] }
 futures = "0.3"
 tracing = { version = "0.1" }
 tokio-util = { version = "0.7" }
@@ -46,6 +45,8 @@ url = { version = "2.4", optional = true }
 # For tower compatibility
 tower-service = { version = "0.3", optional = true }
 
+# for child process transport
+process-wrap = { version = "8.2", features = ["tokio1"], optional = true}
 
 # for ws transport
 # tokio-tungstenite ={ version = "0.26", optional = true }
@@ -66,7 +67,11 @@ macros = ["dep:rmcp-macros", "dep:paste"]
 transport-sse = ["dep:reqwest", "dep:sse-stream", "dep:url"]
 transport-async-rw = ["tokio/io-util", "tokio-util/codec"]
 transport-io = ["transport-async-rw", "tokio/io-std"]
-transport-child-process = ["transport-async-rw", "tokio/process"]
+transport-child-process = [
+    "transport-async-rw",
+    "tokio/process",
+    "dep:process-wrap",
+]
 transport-sse-server = [
     "transport-async-rw",
     "dep:axum",

crates/rmcp/tests/test_with_js.rs

@@ -53,9 +53,9 @@ async fn test_with_js_server() -> anyhow::Result<()> {
         .spawn()?
         .wait()
         .await?;
-    let transport = TokioChildProcess::new(
-        tokio::process::Command::new("node").arg("tests/test_with_js/server.js"),
-    )?;
+    let mut cmd = tokio::process::Command::new("node");
+    cmd.arg("tests/test_with_js/server.js");
+    let transport = TokioChildProcess::new(cmd)?;
 
     let client = ().serve(transport).await?;
     let resources = client.list_all_resources().await?;

crates/rmcp/tests/test_with_python.rs

@@ -54,11 +54,10 @@ async fn test_with_python_server() -> anyhow::Result<()> {
         .spawn()?
         .wait()
         .await?;
-    let transport = TokioChildProcess::new(
-        tokio::process::Command::new("uv")
-            .arg("run")
-            .arg("tests/test_with_python/server.py"),
-    )?;
+    let mut cmd = tokio::process::Command::new("uv");
+    cmd.arg("run");
+    cmd.arg("tests/test_with_python/server.py");
+    let transport = TokioChildProcess::new(cmd)?;
 
     let client = ().serve(transport).await?;
     let resources = client.list_all_resources().await?;

examples/clients/src/collection.rs

@@ -18,11 +18,11 @@ async fn main() -> Result<()> {
 
     let mut client_list = HashMap::new();
     for idx in 0..10 {
+        let mut cmd = Command::new("uvx");
+        cmd.arg("mcp-client-git");
         let service = ()
             .into_dyn()
-            .serve(TokioChildProcess::new(
-                Command::new("uvx").arg("mcp-server-git"),
-            )?)
+            .serve(TokioChildProcess::new(cmd)?)
             .await?;
         client_list.insert(idx, service);
     }

examples/clients/src/everything_stdio.rs

@@ -20,13 +20,10 @@ async fn main() -> Result<()> {
         .init();
 
     // Start server
-    let service = ()
-        .serve(TokioChildProcess::new(
-            Command::new("npx")
-                .arg("-y")
-                .arg("@modelcontextprotocol/server-everything"),
-        )?)
-        .await?;
+    let mut cmd = Command::new("npx");
+    cmd.arg("-y");
+    cmd.arg("@modelcontextprotocol/server-everything");
+    let service = ().serve(TokioChildProcess::new(cmd)?).await?;
 
     // Initialize
     let server_info = service.peer_info();

examples/clients/src/std_io.rs

@@ -13,10 +13,10 @@ async fn main() -> Result<()> {
         )
         .with(tracing_subscriber::fmt::layer())
         .init();
+    let mut cmd = Command::new("uvx");
+    cmd.arg("mcp-server-git");
     let service = ()
-        .serve(TokioChildProcess::new(
-            Command::new("uvx").arg("mcp-server-git"),
-        )?)
+        .serve(TokioChildProcess::new(cmd)?)
         .await?;
 
     // or

examples/rig-integration/src/config/mcp.rs

@@ -69,12 +69,11 @@ impl McpServerTransportConfig {
                 args,
                 envs,
             } => {
-                let transport = rmcp::transport::TokioChildProcess::new(
-                    tokio::process::Command::new(command)
-                        .args(args)
-                        .envs(envs)
-                        .stderr(Stdio::null()),
-                )?;
+                let mut cmd = tokio::process::Command::new(command);
+                cmd.args(args);
+                cmd.envs(envs);
+                cmd.stderr(Stdio::null());
+                let transport = rmcp::transport::TokioChildProcess::new(cmd)?;
                 ().serve(transport).await?
             }
         };