Add proxy functionality. Re-enable local conf.

app/navigate-server/src/main/resources/conf/app.conf

@@ -37,6 +37,8 @@ web-server {
     insecure-port = 7071
     # External url used for redirects
     external-base-url = "navigate.hi.gemini.edu"
+    # Uri to forward requests made to /proxy to.
+    proxy-base-uri = "https://localhost:8080"
 }
 
 # Configuration of the navigate engine

modules/model/jvm/src/main/scala/navigate/model/config/WebServerConfiguration.scala

@@ -4,6 +4,7 @@
 package navigate.model.config
 
 import cats.Eq
+import org.http4s.Uri
 
 import java.nio.file.Path
 
@@ -43,7 +44,8 @@ case class WebServerConfiguration(
   host:            String,
   port:            Int,
   insecurePort:    Int,
-  externalBaseUrl: String
+  externalBaseUrl: String,
+  proxyBaseUri:    Uri
 ) {
   // FIXME Pureconfig can't load this anymore
   val tls: Option[TLSConfig] = None

modules/web/server/src/main/resources/app.conf

@@ -37,6 +37,8 @@ web-server {
     insecure-port = 7071
     # External url used for redirects
     external-base-url = "localhost"
+    # Uri to forward requests made to /proxy to.
+    proxy-base-uri = "https://localhost:8080"
 }
 
 # Configuration of the navigate engine

modules/web/server/src/main/scala/navigate/web/server/http4s/ProxyBuilder.scala

@@ -0,0 +1,37 @@
+// Copyright (c) 2016-2023 Association of Universities for Research in Astronomy, Inc. (AURA)
+// For license information see LICENSE or https://opensource.org/licenses/BSD-3-Clause
+
+package navigate.web.server.http4s
+
+import cats.data.OptionT
+import cats.effect.Async
+import cats.effect.kernel.Resource
+import cats.syntax.all.*
+import fs2.io.net.Network
+import org.http4s.HttpRoutes
+import org.http4s.Uri
+import org.http4s.ember.client.EmberClientBuilder
+import org.http4s.headers._
+
+object ProxyBuilder:
+  def buildService[F[_]: Async: Network](
+    baseUri:   Uri,
+    localPath: Uri.Path
+  ): Resource[F, HttpRoutes[F]] =
+    val remoteBaseHost: String = baseUri.host.map(_.toString).orEmpty
+    val localPathElements: Int = localPath.segments.length
+
+    EmberClientBuilder
+      .default[F]
+      .build
+      .map(
+        _.toHttpApp
+          .mapK(OptionT.liftK) // Turns HttpApp into HttpRoutes
+          .local: req =>
+            req
+              .withUri(
+                // Drop the local path (eg: "/proxy")
+                baseUri.resolve(req.uri.withPath(req.uri.path.splitAt(localPathElements)._2))
+              )
+              .putHeaders(Host(remoteBaseHost))
+      )

modules/web/server/src/main/scala/navigate/web/server/http4s/WebServerLauncher.scala

@@ -6,6 +6,7 @@ package navigate.web.server.http4s
 import cats.Parallel
 import cats.effect.*
 import cats.effect.std.Dispatcher
+import cats.effect.syntax.all.*
 import cats.syntax.all.*
 import ch.qos.logback.classic.spi.ILoggingEvent
 import ch.qos.logback.core.Appender
@@ -14,6 +15,7 @@ import fs2.Stream
 import fs2.compression.Compression
 import fs2.concurrent.Topic
 import fs2.io.file.Files
+import fs2.io.net.Network
 import natchez.Trace.Implicits.noop
 import navigate.model.NavigateEvent
 import navigate.model.config.*
@@ -30,6 +32,7 @@ import navigate.web.server.config.*
 import navigate.web.server.logging.SubscriptionAppender
 import navigate.web.server.security.AuthenticationService
 import org.http4s.HttpRoutes
+import org.http4s.Uri
 import org.http4s.blaze.server.BlazeServerBuilder
 import org.http4s.client.Client
 import org.http4s.ember.client.EmberClientBuilder
@@ -53,15 +56,22 @@ import javax.net.ssl.SSLContext
 import javax.net.ssl.TrustManagerFactory
 import scala.concurrent.duration.*
 
-object WebServerLauncher extends IOApp with LogInitialization {
+object WebServerLauncher extends IOApp with LogInitialization:
+  private val ProxyRoute: Uri.Path = Uri.Path.empty / "db"
+
   private given Logger[IO] = Slf4jLogger.getLoggerFromName[IO]("navigate")
 
   // Attempt to get the configuration file relative to the base dir
   def configurationFile[F[_]: Sync]: F[FilePath] =
     baseDir[F].map(_.resolve("conf").resolve("app.conf"))
 
   def config[F[_]: Sync]: F[ConfigObjectSource] =
-    configurationFile.map(ConfigSource.file)
+    val defaultConfig = ConfigSource.resources("app.conf").pure[F]
+    val fileConfig    = configurationFile.map(ConfigSource.file)
+
+    // ConfigSource, first attempt the file or default to the classpath/resources file
+    (fileConfig, defaultConfig).mapN: (file, default) =>
+      file.optional.withFallback(default.optional)
 
   /** Configures the Authentication service */
   def authService[F[_]: Sync: Logger](
@@ -103,39 +113,44 @@ object WebServerLauncher extends IOApp with LogInitialization {
   }
 
   /** Resource that yields the running web server */
-  def webServer[F[_]: Logger: Async: Dns: Files: Compression](
+  def webServer[F[_]: Logger: Async: Dns: Files: Compression: Network](
     conf:      NavigateConfiguration,
     as:        AuthenticationService[F],
     outputs:   Topic[F, NavigateEvent],
     logTopic:  Topic[F, ILoggingEvent],
     se:        NavigateEngine[F],
     clientsDb: ClientsSetDb[F]
   ): Resource[F, Server] = {
-
     val ssl: F[Option[SSLContext]] = conf.webServer.tls.map(makeContext[F]).sequence
 
-    def build(all: WebSocketBuilder2[F] => HttpRoutes[F]): Resource[F, Server] = Resource.eval {
-      val builder =
-        BlazeServerBuilder[F]
-          .bindHttp(conf.webServer.port, conf.webServer.host)
-          .withHttpWebSocketApp(wsb => all(wsb).orNotFound)
-      ssl.map(_.fold(builder)(builder.withSslContext)).map(_.resource)
-    }.flatten
-
-    def router(wsBuilder: WebSocketBuilder2[F]) = Router[F](
-      "/"         -> new StaticRoutes().service,
-      "/navigate" -> new GraphQlRoutes(se, logTopic).service(wsBuilder)
+    def router(wsBuilder: WebSocketBuilder2[F], proxyService: HttpRoutes[F]) = Router[F](
+      "/"                 -> new StaticRoutes().service,
+      "/navigate"         -> new GraphQlRoutes(se, logTopic).service(wsBuilder),
+      ProxyRoute.toString -> proxyService
     )
 
     val pingRouter = Router[F](
       "/ping" -> new PingRoutes(as).service
     )
 
-    def loggedRoutes(wsBuilder: WebSocketBuilder2[F]) =
-      pingRouter <+> Http4sLogger.httpRoutes(logHeaders = false, logBody = false)(router(wsBuilder))
-
-    build(loggedRoutes)
-
+    def loggedRoutes(wsBuilder: WebSocketBuilder2[F], proxyService: HttpRoutes[F]) =
+      pingRouter <+>
+        Http4sLogger.httpRoutes(logHeaders = false, logBody = false)(
+          router(wsBuilder, proxyService)
+        )
+
+    def builder(proxyService: HttpRoutes[F]) =
+      BlazeServerBuilder[F]
+        .bindHttp(conf.webServer.port, conf.webServer.host)
+        .withHttpWebSocketApp(wsb => loggedRoutes(wsb, proxyService).orNotFound)
+
+    for
+      proxyService <- ProxyBuilder.buildService[F](conf.webServer.proxyBaseUri, ProxyRoute)
+      server       <- ssl
+                        .map(_.fold(builder(proxyService))(builder(proxyService).withSslContext).resource)
+                        .toResource
+                        .flatten
+    yield server
   }
 
   def redirectWebServer[F[_]: Async](conf: WebServerConfiguration): Resource[F, Server] = {
@@ -284,5 +299,3 @@ object WebServerLauncher extends IOApp with LogInitialization {
       if (oc.isSuccess) IO.unit
       else IO(Console.println(s"Exit code $oc")) // scalastyle:off console.io
     }
-
-}