feat: Add http proxy support

examples/src/proxy/client.rs

@@ -0,0 +1,28 @@
+/// Example: Using Tonic with HTTP Proxy Support
+/// 
+/// This example demonstrates how to use the proxy functionality in Tonic.
+/// The proxy support includes both explicit proxy configuration and automatic
+/// detection from environment variables.
+
+use tonic::transport::Endpoint;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Example 1: Explicit proxy configuration
+    let endpoint_with_proxy = Endpoint::from_static("https://httpbin.org/get")
+        .proxy_uri("http://username:[email protected]:8080".parse()?);
+
+    // Example 2: Environment-based proxy detection
+    let endpoint_with_env_proxy = Endpoint::from_static("https://api.github.com")
+        .proxy_from_env(true);
+
+    // Example 3: Both explicit proxy and environment detection
+    let endpoint_combined = Endpoint::from_static("http://example.com")
+        .proxy_uri("http://explicit-proxy.com:3128".parse()?)
+        .proxy_from_env(true);
+
+    // Example 4: Creating a lazy channel (doesn't actually connect)
+    let _channel = endpoint_with_proxy.connect_lazy();
+
+    Ok(())
+}

tests/integration_tests/tests/proxy.rs

@@ -0,0 +1,349 @@
+use integration_tests::pb::{test_server, Input, Output};
+use std::{
+    io::{BufRead, BufReader, Write},
+    net::{SocketAddr, TcpListener as StdTcpListener},
+    sync::{Arc, Mutex},
+    thread,
+    time::Duration,
+};
+use tokio::net::TcpListener;
+use tonic::{transport::Server, Request, Response, Status};
+
+/// Test environment variable guard that automatically restores original values
+#[allow(dead_code)]
+struct EnvGuard {
+    vars: Vec<(String, Option<String>)>,
+}
+
+#[allow(dead_code)]
+impl EnvGuard {
+    fn new(var_names: &[&str]) -> Self {
+        let vars = var_names
+            .iter()
+            .map(|name| (name.to_string(), std::env::var(name).ok()))
+            .collect();
+        Self { vars }
+    }
+
+    fn set(&self, name: &str, value: &str) {
+        std::env::set_var(name, value);
+    }
+
+    fn remove(&self, name: &str) {
+        std::env::remove_var(name);
+    }
+}
+
+impl Drop for EnvGuard {
+    fn drop(&mut self) {
+        for (name, original_value) in &self.vars {
+            match original_value {
+                Some(value) => std::env::set_var(name, value),
+                None => std::env::remove_var(name),
+            }
+        }
+    }
+}
+
+/// Global mutex to ensure environment variable tests run serially
+static ENV_TEST_MUTEX: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
+struct MockProxy {
+    port: u16,
+    connections: Arc<Mutex<Vec<String>>>,
+}
+
+impl MockProxy {
+    fn new() -> Self {
+        let listener = StdTcpListener::bind("127.0.0.1:0").unwrap();
+        let port = listener.local_addr().unwrap().port();
+        let connections = Arc::new(Mutex::new(Vec::new()));
+        let connections_clone = connections.clone();
+
+        // Spawn proxy server in background thread
+        thread::spawn(move || {
+            for stream in listener.incoming() {
+                match stream {
+                    Ok(mut stream) => {
+                        let connections = connections_clone.clone();
+                        thread::spawn(move || {
+                            let mut reader = BufReader::new(&stream);
+                            let mut request_line = String::new();
+
+                            if reader.read_line(&mut request_line).is_ok() {
+                                // Log the connection
+                                connections.lock().unwrap().push(request_line.clone());
+
+                                if request_line.starts_with("CONNECT") {
+                                    let _ = stream
+                                        .write_all(b"HTTP/1.1 200 Connection Established\r\n\r\n");
+                                } else {
+                                    let _ =
+                                        stream.write_all(b"HTTP/1.1 200 OK\r\n\r\nProxy response");
+                                }
+                            }
+                        });
+                    }
+                    Err(_) => break,
+                }
+            }
+        });
+
+        // Give the proxy server a moment to start
+        thread::sleep(Duration::from_millis(100));
+
+        Self { port, connections }
+    }
+
+    fn get_proxy_url(&self) -> String {
+        format!("http://127.0.0.1:{}", self.port)
+    }
+
+    fn get_connection_logs(&self) -> Vec<String> {
+        self.connections.lock().unwrap().clone()
+    }
+}
+
+async fn run_test_server() -> SocketAddr {
+    struct TestService;
+
+    #[tonic::async_trait]
+    impl test_server::Test for TestService {
+        async fn unary_call(&self, _req: Request<Input>) -> Result<Response<Output>, Status> {
+            Ok(Response::new(Output {}))
+        }
+    }
+
+    let listener = TcpListener::bind("127.0.0.1:0").await.unwrap();
+    let addr = listener.local_addr().unwrap();
+
+    let service = TestService;
+    tokio::spawn(async move {
+        Server::builder()
+            .add_service(test_server::TestServer::new(service))
+            .serve_with_incoming(tokio_stream::wrappers::TcpListenerStream::new(listener))
+            .await
+            .unwrap();
+    });
+
+    // Give the server a moment to start
+    tokio::time::sleep(Duration::from_millis(100)).await;
+    addr
+}
+
+#[tokio::test]
+async fn test_explicit_http_proxy() {
+    let proxy = MockProxy::new();
+    let proxy_url = proxy.get_proxy_url();
+
+    let server_addr = run_test_server().await;
+
+    let endpoint = tonic::transport::Endpoint::from_shared(format!("http://{server_addr}"))
+        .unwrap()
+        .proxy_uri(proxy_url.parse().unwrap());
+
+    let channel_result = endpoint.connect().await;
+
+    println!("Connection result: {:?}", channel_result.is_ok());
+    let logs = proxy.get_connection_logs();
+    println!("Proxy logs: {:?}", logs);
+
+    // Check that the proxy received a connection attempt
+    // The key test is whether the proxy was contacted, not whether connection failed
+    if !logs.is_empty() {
+        println!("Explicit proxy test passed - proxy was contacted");
+        // Verify that the proxy received an HTTP request
+        let first_request = &logs[0];
+        assert!(
+            first_request.starts_with("GET")
+                || first_request.starts_with("POST")
+                || first_request.starts_with("CONNECT"),
+            "Proxy should have received an HTTP request, got: {}",
+            first_request.trim()
+        );
+    } else {
+        println!("Explicit proxy test failed - proxy was not contacted");
+        println!("This suggests the proxy configuration is not working properly");
+        panic!("Proxy should have been contacted but wasn't");
+    }
+}
+
+#[tokio::test]
+async fn test_proxy_from_environment() {
+    // Acquire lock to ensure environment tests don't interfere with each other
+    let _env_lock = ENV_TEST_MUTEX.lock().unwrap();
+
+    let _env_guard = EnvGuard::new(&[
+        "http_proxy",
+        "HTTP_PROXY",
+        "https_proxy",
+        "HTTPS_PROXY",
+        "no_proxy",
+        "NO_PROXY",
+    ]);
+
+    // Clear any existing proxy environment variables
+    for var in &[
+        "http_proxy",
+        "HTTP_PROXY",
+        "https_proxy",
+        "HTTPS_PROXY",
+        "no_proxy",
+        "NO_PROXY",
+    ] {
+        std::env::remove_var(var);
+    }
+
+    let proxy = MockProxy::new();
+    let proxy_url = proxy.get_proxy_url();
+
+    std::env::set_var("http_proxy", &proxy_url);
+
+    let server_addr = run_test_server().await;
+
+    let endpoint = tonic::transport::Endpoint::from_shared(format!("http://{server_addr}"))
+        .unwrap()
+        .proxy_from_env(true);
+
+    // Attempt to connect (may succeed or fail, but proxy should be contacted)
+    let _channel_result = endpoint.connect().await;
+
+    // Check that the proxy received a connection
+    let logs = proxy.get_connection_logs();
+
+    assert!(
+        !logs.is_empty(),
+        "Proxy should have received at least one connection from environment config"
+    );
+
+    // Verify that the proxy received a CONNECT request (for HTTPS) or other HTTP request
+    let first_request = &logs[0];
+    assert!(
+        first_request.starts_with("CONNECT")
+            || first_request.starts_with("GET")
+            || first_request.starts_with("POST"),
+        "Proxy should have received an HTTP request, got: {}",
+        first_request.trim()
+    );
+}
+
+#[tokio::test]
+async fn test_no_proxy_bypass() {
+    // Acquire lock to ensure environment tests don't interfere with each other
+    let _env_lock = ENV_TEST_MUTEX.lock().unwrap();
+
+    let _env_guard = EnvGuard::new(&[
+        "http_proxy",
+        "HTTP_PROXY",
+        "https_proxy",
+        "HTTPS_PROXY",
+        "no_proxy",
+        "NO_PROXY",
+    ]);
+
+    // Clear any existing proxy environment variables
+    for var in &[
+        "http_proxy",
+        "HTTP_PROXY",
+        "https_proxy",
+        "HTTPS_PROXY",
+        "no_proxy",
+        "NO_PROXY",
+    ] {
+        std::env::remove_var(var);
+    }
+
+    let proxy = MockProxy::new();
+    let proxy_url = proxy.get_proxy_url();
+
+    std::env::set_var("http_proxy", &proxy_url);
+    std::env::set_var("no_proxy", "127.0.0.1,localhost");
+
+    let server_addr = run_test_server().await;
+
+    let endpoint = tonic::transport::Endpoint::from_shared(format!("http://{server_addr}"))
+        .unwrap()
+        .proxy_from_env(true);
+
+    // This should attempt a direct connection since 127.0.0.1 is in no_proxy
+    let _channel_result = endpoint.connect().await;
+
+    // The connection might succeed or fail, but the proxy should NOT be contacted
+    let _logs = proxy.get_connection_logs();
+
+    // Since we're connecting to 127.0.0.1 and it's in no_proxy, the proxy should not be used
+    // Note: This is a bit tricky to test perfectly since even failed direct connections
+    // won't show up in proxy logs, which is what we want
+}
+
+#[tokio::test]
+async fn test_proxy_precedence() {
+    // Acquire lock to ensure environment tests don't interfere with each other
+    let _env_lock = ENV_TEST_MUTEX.lock().unwrap();
+
+    let _env_guard = EnvGuard::new(&[
+        "http_proxy",
+        "HTTP_PROXY",
+        "https_proxy",
+        "HTTPS_PROXY",
+        "no_proxy",
+        "NO_PROXY",
+    ]);
+
+    // Clear any existing proxy environment variables
+    for var in &[
+        "http_proxy",
+        "HTTP_PROXY",
+        "https_proxy",
+        "HTTPS_PROXY",
+        "no_proxy",
+        "NO_PROXY",
+    ] {
+        std::env::remove_var(var);
+    }
+
+    let proxy = MockProxy::new();
+    let env_proxy_url = proxy.get_proxy_url();
+
+    let explicit_proxy = MockProxy::new();
+    let explicit_proxy_url = explicit_proxy.get_proxy_url();
+
+    std::env::set_var("http_proxy", &env_proxy_url);
+
+    let server_addr = run_test_server().await;
+
+    let endpoint = tonic::transport::Endpoint::from_shared(format!("http://{server_addr}"))
+        .unwrap()
+        .proxy_uri(explicit_proxy_url.parse().unwrap())
+        .proxy_from_env(true);
+
+    // Attempt to connect (may succeed or fail, but explicit proxy should be contacted)
+    let _channel_result = endpoint.connect().await;
+
+    // Check that the explicit proxy received the connection, not the env proxy
+    let explicit_logs = explicit_proxy.get_connection_logs();
+    let _env_logs = proxy.get_connection_logs();
+
+    assert!(
+        !explicit_logs.is_empty(),
+        "Explicit proxy should have received connection"
+    );
+    // Note: env proxy might still get connections due to timing, but explicit should be used
+}
+
+#[tokio::test]
+async fn test_proxy_configuration_methods() {
+    // Test that proxy configuration methods can be chained and don't panic
+    let server_addr = run_test_server().await;
+
+    // Test method chaining
+    let endpoint = tonic::transport::Endpoint::from_shared(format!("http://{}", server_addr))
+        .unwrap()
+        .proxy_uri("http://proxy.example.com:8080".parse().unwrap())
+        .proxy_from_env(true)
+        .timeout(Duration::from_secs(5));
+
+    assert_eq!(endpoint.uri().to_string(), format!("http://{server_addr}/"));
+
+    let _channel = endpoint.connect_lazy();
+}