add admin_http post forwarding

Cargo.lock

@@ -1677,6 +1677,7 @@ dependencies = [
  "dotenvy",
  "hyper",
  "hyper-util",
+ "reqwest",
  "signal-gateway",
  "syslog_rfc5424",
  "tokio",

signal-gateway-bin/Cargo.toml

@@ -23,6 +23,7 @@ conf-extra = { workspace = true }
 dotenvy = { workspace = true }
 hyper = { workspace = true }
 hyper-util = { workspace = true }
+reqwest = { workspace = true }
 syslog_rfc5424 = { workspace = true }
 tokio = { workspace = true, features = ["rt-multi-thread", "signal"] }
 tokio-util = { workspace = true }

signal-gateway-bin/src/admin_http/mod.rs

@@ -0,0 +1,64 @@
+//! Admin HTTP client for forwarding messages to an HTTP server
+//!
+//! This module handles admin messages not handled by the gateway by making an HTTP POST request
+//! with the message as the body, and returning the response body as the reply.
+
+use conf::Conf;
+use signal_gateway::{AdminMessageResponse, MessageHandler, MessageHandlerResult};
+use std::time::Duration;
+
+/// Configuration for the admin HTTP client
+#[derive(Clone, Conf, Debug)]
+pub struct AdminHttpConfig {
+    /// URL to POST admin commands to
+    #[conf(long, env)]
+    pub url: String,
+    /// Timeout for the HTTP request
+    #[conf(long, env, default_value = "5s", value_parser = conf_extra::parse_duration)]
+    pub timeout: Duration,
+}
+
+impl AdminHttpConfig {
+    /// Create a message handler function from this config.
+    ///
+    /// The returned handler makes an HTTP POST request to the configured URL
+    /// with the message as the body, and returns the response body.
+    pub fn into_handler(self) -> MessageHandler {
+        let client = reqwest::Client::builder()
+            .timeout(self.timeout)
+            .build()
+            .expect("Failed to build HTTP client");
+
+        Box::new(move |message: String| {
+            let client = client.clone();
+            let url = self.url.clone();
+            Box::pin(async move { handle_message(&client, &url, message).await })
+        })
+    }
+}
+
+/// Handle a message by POSTing it to the configured HTTP server
+async fn handle_message(
+    client: &reqwest::Client,
+    url: &str,
+    message: String,
+) -> MessageHandlerResult {
+    let response = client
+        .post(url)
+        .body(message)
+        .send()
+        .await
+        .map_err(|err| (502u16, format!("HTTP request failed: {err}").into()))?;
+
+    let status = response.status();
+    let body = response
+        .text()
+        .await
+        .map_err(|err| (502u16, format!("Failed to read response body: {err}").into()))?;
+
+    if !status.is_success() {
+        return Err((status.as_u16(), body.into()));
+    }
+
+    Ok(AdminMessageResponse::new(body))
+}

signal-gateway-bin/src/main.rs

@@ -1,20 +1,44 @@
-use conf::Conf;
+use conf::{Conf, Subcommands};
 use hyper::service::service_fn;
 use hyper_util::rt::TokioIo;
 use hyper_util::server::conn::auto;
-use signal_gateway::{Gateway, GatewayConfig};
+use signal_gateway::{Gateway, GatewayConfig, MessageHandler};
 use std::{net::SocketAddr, sync::Arc, time::Duration};
 use tokio::net::TcpListener;
 use tokio_util::sync::CancellationToken;
 use tracing::{error, info, warn};
 use tracing_subscriber::EnvFilter;
 
+mod admin_http;
+use admin_http::AdminHttpConfig;
+
 mod admin_netcat;
 use admin_netcat::AdminNetcatConfig;
 
 mod syslog;
 use syslog::SyslogUdpConfig;
 
+/// Admin message handler configuration - select how non-command messages are handled
+#[derive(Clone, Debug, Subcommands)]
+enum AdminHandlerCommand {
+    /// Forward (unhandled) admin messages to a TCP endpoint (netcat-style)
+    /// Useful if an http server would be heavy in the target process
+    #[conf(name = "admin-netcat")]
+    Netcat(AdminNetcatConfig),
+    /// Forward (unhandled) admin messages to an HTTP endpoint via POST
+    #[conf(name = "admin-http")]
+    Http(AdminHttpConfig),
+}
+
+impl AdminHandlerConfig {
+    fn into_handler(self) -> MessageHandler {
+        match self {
+            AdminHandlerConfig::Netcat(config) => config.into_handler(),
+            AdminHandlerConfig::Http(config) => config.into_handler(),
+        }
+    }
+}
+
 #[derive(Conf, Debug)]
 struct Config {
     /// If true, just validate config and don't start
@@ -25,8 +49,9 @@ struct Config {
     http_listen_addr: SocketAddr,
     #[conf(flatten, prefix)]
     syslog_udp: Option<SyslogUdpConfig>,
-    #[conf(flatten, prefix)]
-    admin_netcat: Option<AdminNetcatConfig>,
+    /// Optional admin message handler (netcat or http)
+    #[conf(subcommands)]
+    admin_handler: Option<AdminHandlerCommand>,
     #[conf(flatten)]
     gateway: GatewayConfig,
 }
@@ -73,7 +98,7 @@ async fn main() {
 
     let token = CancellationToken::new();
 
-    let message_handler = config.admin_netcat.map(|c| c.into_handler());
+    let message_handler = config.admin_handler.map(|c| c.into_handler());
     let gateway = Arc::new(Gateway::new(config.gateway, token.clone(), message_handler).await);
 
     let listener = TcpListener::bind(config.http_listen_addr).await.unwrap();