Implement AutoHostRewrite functionality in request handling

orion-configuration/src/config/network_filters/http_connection_manager/route.rs

@@ -38,7 +38,6 @@ use std::{
     str::FromStr,
     time::Duration,
 };
-
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]
 pub enum Action {
@@ -132,6 +131,47 @@ impl PathRewriteSpecifier {
     }
 }
 
+impl AuthorityRewriteSpecifier {
+    /// Applies authority rewrite based on the specifier type
+    pub fn apply(
+        &self,
+        uri: &http::Uri,
+        headers: &http::HeaderMap,
+        upstream_authority: &Authority,
+    ) -> Option<Authority> {
+        match self {
+            AuthorityRewriteSpecifier::Authority(authority) => Some(authority.clone()),
+
+            AuthorityRewriteSpecifier::Header(header_name) => {
+                let Some(header_value) = headers.get(header_name.as_str()) else {
+                    return None;
+                };
+                let Ok(header_str) = header_value.to_str() else {
+                    return None;
+                };
+                Authority::from_str(header_str).ok()
+            },
+
+            AuthorityRewriteSpecifier::Regex(regex) => {
+                let current_authority = uri
+                    .authority()
+                    .map(Authority::as_str)
+                    .or_else(|| headers.get(http::header::HOST).and_then(|h| h.to_str().ok()))
+                    .unwrap_or_default();
+
+                let replacement = regex.pattern.replace_all(current_authority, regex.substitution.as_str());
+                if let std::borrow::Cow::Borrowed(_) = replacement {
+                    None
+                } else {
+                    Authority::from_str(&replacement).ok()
+                }
+            },
+
+            AuthorityRewriteSpecifier::AutoHostRewrite => Some(upstream_authority.clone()),
+        }
+    }
+}
+
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq, Eq)]
 pub struct RedirectAction {
     pub response_code: RedirectResponseCode,
@@ -649,6 +689,87 @@ mod tests {
         let result = route_match.match_request(&req);
         assert!(!result.matched());
     }
+
+    #[test]
+    fn test_authority_rewrite_auto_host_rewrite() {
+        let authority_rewrite = AuthorityRewriteSpecifier::AutoHostRewrite;
+        let upstream_authority = Authority::from_str("upstream.example.com:8080").unwrap();
+        let uri = "http://original.example.com/path".parse::<http::Uri>().unwrap();
+        let mut headers = http::HeaderMap::new();
+        headers.insert("host", "original.example.com".parse().unwrap());
+
+        let result = authority_rewrite.apply(&uri, &headers, &upstream_authority);
+        assert_eq!(result, Some(upstream_authority));
+    }
+
+    #[test]
+    fn test_authority_rewrite_specific_authority() {
+        let target_authority = Authority::from_str("target.example.com:9090").unwrap();
+        let authority_rewrite = AuthorityRewriteSpecifier::Authority(target_authority.clone());
+        let upstream_authority = Authority::from_str("upstream.example.com:8080").unwrap();
+        let uri = "http://original.example.com/path".parse::<http::Uri>().unwrap();
+        let mut headers = http::HeaderMap::new();
+        headers.insert("host", "original.example.com".parse().unwrap());
+
+        let result = authority_rewrite.apply(&uri, &headers, &upstream_authority);
+        assert_eq!(result, Some(target_authority));
+    }
+
+    #[test]
+    fn test_authority_rewrite_header() {
+        let authority_rewrite = AuthorityRewriteSpecifier::Header("x-target-host".into());
+        let upstream_authority = Authority::from_str("upstream.example.com:8080").unwrap();
+        let uri = "http://original.example.com/path".parse::<http::Uri>().unwrap();
+        let mut headers = http::HeaderMap::new();
+        headers.insert("host", "original.example.com".parse().unwrap());
+        headers.insert("x-target-host", "header.example.com:7070".parse().unwrap());
+
+        let result = authority_rewrite.apply(&uri, &headers, &upstream_authority);
+        assert_eq!(result, Some(Authority::from_str("header.example.com:7070").unwrap()));
+    }
+
+    #[test]
+    fn test_authority_rewrite_header_missing() {
+        let authority_rewrite = AuthorityRewriteSpecifier::Header("x-missing-header".into());
+        let upstream_authority = Authority::from_str("upstream.example.com:8080").unwrap();
+        let uri = "http://original.example.com/path".parse::<http::Uri>().unwrap();
+        let mut headers = http::HeaderMap::new();
+        headers.insert("host", "original.example.com".parse().unwrap());
+
+        let result = authority_rewrite.apply(&uri, &headers, &upstream_authority);
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_authority_rewrite_regex() {
+        let regex = RegexMatchAndSubstitute {
+            pattern: Regex::new(r"^([^.]+)\.original\.com$").unwrap(),
+            substitution: "${1}.rewritten.com".into(),
+        };
+        let authority_rewrite = AuthorityRewriteSpecifier::Regex(regex);
+        let upstream_authority = Authority::from_str("upstream.example.com:8080").unwrap();
+        let uri = "http://api.original.com/path".parse::<http::Uri>().unwrap();
+        let mut headers = http::HeaderMap::new();
+        headers.insert("host", "api.original.com".parse().unwrap());
+
+        let result = authority_rewrite.apply(&uri, &headers, &upstream_authority);
+        assert_eq!(result, Some(Authority::from_str("api.rewritten.com").unwrap()));
+    }
+
+    #[test]
+    fn test_authority_rewrite_regex_no_host_header() {
+        let regex = RegexMatchAndSubstitute {
+            pattern: Regex::new(r"^([^.]+)\.original\.com$").unwrap(),
+            substitution: "${1}.rewritten.com".into(),
+        };
+        let authority_rewrite = AuthorityRewriteSpecifier::Regex(regex);
+        let upstream_authority = Authority::from_str("upstream.example.com:8080").unwrap();
+        let uri = "/path".parse::<http::Uri>().unwrap();
+        let headers = http::HeaderMap::new();
+
+        let result = authority_rewrite.apply(&uri, &headers, &upstream_authority);
+        assert_eq!(result, None);
+    }
 }
 
 #[cfg(feature = "envoy-conversions")]

orion-lib/src/listeners/http_connection_manager/route.rs

@@ -97,16 +97,30 @@ impl<'a> RequestHandler<(MatchedRequest<'a>, &HttpConnectionManager)> for &Route
                     } else {
                         None
                     };
-                    if path_and_query_replacement.is_some() {
+
+                    let authority_replacement = if let Some(authority_rewrite) = &self.authority_rewrite {
+                        authority_rewrite.apply(&parts.uri, &parts.headers, &svc_channel.upstream_authority)
+                    } else {
+                        None
+                    };
+
+                    if path_and_query_replacement.is_some() || authority_replacement.is_some() {
                         parts.uri = {
-                            let UriParts { scheme, authority, path_and_query: _, .. } = parts.uri.into_parts();
+                            let UriParts { scheme, authority, path_and_query, .. } = parts.uri.into_parts();
                             let mut new_parts = UriParts::default();
                             new_parts.scheme = scheme;
-                            new_parts.authority = authority;
-                            new_parts.path_and_query = path_and_query_replacement;
-                            Uri::from_parts(new_parts).with_context_msg("failed to replace request path_and_query")?
+                            new_parts.authority = authority_replacement.clone().or(authority);
+                            new_parts.path_and_query = path_and_query_replacement.or(path_and_query);
+                            Uri::from_parts(new_parts).with_context_msg("failed to replace request URI")?
                         }
                     }
+
+                    if let Some(new_authority) = &authority_replacement {
+                        let header_value = http::HeaderValue::from_str(new_authority.as_str())
+                            .with_context_msg("failed to create Host header value")?;
+                        parts.headers.insert(http::header::HOST, header_value);
+                    }
+
                     Request::from_parts(parts, body.map_into())
                 };