Log cf-ray headers from CloudFlare, if available

Sources/App/Core/CFRayRouteLoggingMiddleware.swift

@@ -0,0 +1,34 @@
+// Copyright Dave Verwer, Sven A. Schmidt, and other contributors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Vapor
+
+
+// Replica of the Vapor RouteLoggingMiddleware that's tweaked to explicitly expose the cf-ray header in the logger metadata for the request.
+public final class CFRayRouteLoggingMiddleware: Middleware {
+    public let logLevel: Logger.Level
+
+    public init(logLevel: Logger.Level = .info) {
+        self.logLevel = logLevel
+    }
+
+    public func respond(to request: Request, chainingTo next: Responder) -> EventLoopFuture<Response> {
+        guard let cfray = request.headers.first(name: "cf-ray") else {
+            return next.respond(to: request)
+        }
+        request.logger[metadataKey: "cf-ray"] = .string(cfray)
+        request.logger.log(level: self.logLevel, "\(request.method) \(request.url.path.removingPercentEncoding ?? request.url.path)")
+        return next.respond(to: request)
+    }
+}

Sources/App/Core/Dependencies/EnvironmentClient.swift

@@ -44,6 +44,7 @@ struct EnvironmentClient {
     var hideStagingBanner: @Sendable () -> Bool = { XCTFail("hideStagingBanner"); return Constants.defaultHideStagingBanner }
     var loadSPIManifest: @Sendable (String) -> SPIManifest.Manifest?
     var maintenanceMessage: @Sendable () -> String?
+    var enableCFRayLogging: @Sendable () -> Bool = { XCTFail("enableCFRayLogging"); return true }
     var mastodonCredentials: @Sendable () -> Mastodon.Credentials?
     var metricsPushGatewayUrl: @Sendable () -> String?
     var plausibleBackendReportingSiteID: @Sendable () -> String?
@@ -116,6 +117,10 @@ extension EnvironmentClient: DependencyKey {
             loadSPIManifest: { path in SPIManifest.Manifest.load(in: path) },
             maintenanceMessage: {
                 Environment.get("MAINTENANCE_MESSAGE").flatMap(\.trimmed)
+            enableCFRayLogging: {
+                Environment.get("ENABLE_CF_RAY_LOGGING")
+                    .flatMap(\.asBool)
+                ?? false
             },
             mastodonCredentials: {
                 Environment.get("MASTODON_ACCESS_TOKEN")
@@ -172,6 +177,7 @@ extension EnvironmentClient: TestDependencyKey {
         mock.hideStagingBanner = { false }
         mock.siteURL = { "http://localhost:8080" }
         mock.shouldFail = { @Sendable _ in false }
+        mock.enableCFRayLogging = { true }
         return mock
     }
 }

Sources/App/configure.swift

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+import Dependencies
 import Fluent
 import FluentPostgresDriver
 import Vapor
@@ -37,6 +38,17 @@ public func configure(_ app: Application) async throws -> String {
     // app.http.server.configuration.responseCompression = .enabled
     // app.http.server.configuration.requestDecompression = .enabled
 
+    @Dependency(\.environment) var environment
+
+    if environment.enableCFRayLogging() {
+        // This stanza replaces the default middleware from Vapor, specifically replacing the
+        // default route logging middleware with the tweaked up version that reports on the cf-ray
+        // header (if any) from CloudFlare.
+        app.middleware = Middlewares()
+        app.middleware.use(Vapor.ErrorMiddleware.default(environment: app.environment))
+        app.middleware.use(CFRayRouteLoggingMiddleware())
+    }
+
     app.middleware.use(FileMiddleware(publicDirectory: app.directory.publicDirectory))
     app.middleware.use(ErrorMiddleware())
 

app.yml

@@ -44,6 +44,7 @@ x-shared: &shared
     DATABASE_USERNAME: ${DATABASE_USERNAME}
     DATABASE_PASSWORD: ${DATABASE_PASSWORD}
     DATABASE_USE_TLS: ${DATABASE_USE_TLS}
+    ENABLE_CF_RAY_LOGGING: ${ENABLE_CF_RAY_LOGGING}
     FAILURE_MODE: ${FAILURE_MODE}
     GITHUB_TOKEN: ${GITHUB_TOKEN}
     GITLAB_API_TOKEN: ${GITLAB_API_TOKEN}