Added `init_downstream_modules` phase allowing modules to be set up before startup

Includes-commit: 1bf3d4dfea191cdcefd37dc42fa5c269fc29ff64
Replicated-from: https://github.com/cloudflare/pingora/pull/284

2 files changed, 22 insertions, 2 deletions

diff --git a/pingora-proxy/src/lib.rs b/pingora-proxy/src/lib.rs
index 0add56a..d89cb4a 100644
--- a/pingora-proxy/src/lib.rs
+++ b/pingora-proxy/src/lib.rs
@@ -110,6 +110,14 @@ impl<SV> HttpProxy<SV> {
         }
     }
 
+    fn handle_init_modules(&mut self)
+    where
+        SV: ProxyHttp,
+    {
+        self.inner
+            .init_downstream_modules(&mut self.downstream_modules);
+    }
+
     async fn handle_new_request(
         &self,
         mut downstream_session: Box<HttpSession>,
@@ -739,7 +747,10 @@ use pingora_core::services::listening::Service;
 /// Create a [Service] from the user implemented [ProxyHttp].
 ///
 /// The returned [Service] can be hosted by a [pingora_core::server::Server] directly.
-pub fn http_proxy_service<SV>(conf: &Arc<ServerConf>, inner: SV) -> Service<HttpProxy<SV>> {
+pub fn http_proxy_service<SV>(conf: &Arc<ServerConf>, inner: SV) -> Service<HttpProxy<SV>>
+where
+    SV: ProxyHttp,
+{
     http_proxy_service_with_name(conf, inner, "Pingora HTTP Proxy Service")
 }
 
@@ -750,11 +761,15 @@ pub fn http_proxy_service_with_name<SV>(
     conf: &Arc<ServerConf>,
     inner: SV,
     name: &str,
-) -> Service<HttpProxy<SV>> {
+) -> Service<HttpProxy<SV>>
+where
+    SV: ProxyHttp,
+{
     let mut proxy = HttpProxy::new(inner, conf.clone());
     // Add disabled downstream compression module by default
     proxy
         .downstream_modules
         .add_module(ResponseCompressionBuilder::enable(0));
+    proxy.handle_init_modules();
     Service::new(name.to_string(), proxy)
 }
diff --git a/pingora-proxy/src/proxy_trait.rs b/pingora-proxy/src/proxy_trait.rs
index 6f429ac..3b83fda 100644
--- a/pingora-proxy/src/proxy_trait.rs
+++ b/pingora-proxy/src/proxy_trait.rs
@@ -40,6 +40,11 @@ pub trait ProxyHttp {
         ctx: &mut Self::CTX,
     ) -> Result<Box<HttpPeer>>;
 
+    /// Set up downstream modules.
+    ///
+    /// In this phase, users can add or configure modules before the server starts up.
+    fn init_downstream_modules(&self, _modules: &mut HttpModules) {}
+
     /// Handle the incoming request.
     ///
     /// In this phase, users can parse, validate, rate limit, perform access control and/or