chore: trace-id and interceptors for ktor server

Author: sureshg

backend/jvm/src/main/kotlin/dev/suresh/App.kt

@@ -3,6 +3,7 @@ package dev.suresh
 import BuildConfig
 import dev.suresh.config.SysConfig
 import dev.suresh.plugins.configureHTTP
+import dev.suresh.plugins.configureInterceptors
 import dev.suresh.plugins.configureOTel
 import dev.suresh.plugins.configureSecurity
 import dev.suresh.plugins.custom.customPlugins
@@ -24,6 +25,7 @@ fun main(args: Array<String>) =
     }
 
 fun Application.module() {
+  configureInterceptors()
   configureHTTP()
   configureSecurity()
   configureOTel()
@@ -35,5 +37,6 @@ fun Application.module() {
     services()
     mgmtRoutes()
   }
+
   // CoroutineScope(coroutineContext).launch {}
 }

backend/jvm/src/main/kotlin/dev/suresh/plugins/Error.kt

@@ -1,32 +1,53 @@
 package dev.suresh.plugins
 
-import io.ktor.http.HttpStatusCode.Companion.BadRequest
-import io.ktor.http.HttpStatusCode.Companion.InternalServerError
-import io.ktor.http.HttpStatusCode.Companion.NotFound
-import io.ktor.http.HttpStatusCode.Companion.Unauthorized
+import dev.suresh.http.*
+import io.ktor.http.HttpStatusCode
 import io.ktor.server.application.*
 import io.ktor.server.plugins.*
 import io.ktor.server.plugins.statuspages.*
 import io.ktor.server.request.*
 import io.ktor.server.response.*
 
 fun Application.errorRoutes() {
+
   install(StatusPages) {
-    status(Unauthorized) { call, _ -> call.respond(Unauthorized, "Unauthorized") }
+    status(HttpStatusCode.Unauthorized) { call, status ->
+      when {
+        call.isApi ->
+            call.respondError(
+                HttpStatusCode.Unauthorized, "Authorization is required to access this resource")
+      }
+    }
 
     exception<Throwable> { call, cause ->
       val status =
           when (cause) {
-            is BadRequestException -> BadRequest
-            else -> InternalServerError
+            is BadRequestException -> HttpStatusCode.BadRequest
+            else -> HttpStatusCode.InternalServerError
           }
 
       call.application.log.error(status.description, cause)
-      call.respond(status, "${cause.message}")
+      call.respondError(status, cause.message ?: "Unknown error", cause)
     }
 
-    unhandled { it.respond(NotFound, "The requested URL ${it.request.path()} was not found") }
+    unhandled {
+      it.respondError(
+          HttpStatusCode.NotFound, "The requested URL ${it.request.path()} was not found")
+    }
   }
 }
 
 fun userError(message: Any): Nothing = throw BadRequestException(message.toString())
+
+suspend fun ApplicationCall.respondError(
+    status: HttpStatusCode,
+    message: String,
+    cause: Throwable? = null
+) =
+    respond(
+        status = status,
+        message =
+            ErrorStatus(
+                code = status.value,
+                message = message,
+                details = if (debug) cause?.stackTraceToString() else cause?.message))

backend/jvm/src/main/kotlin/dev/suresh/plugins/Http.kt

@@ -6,6 +6,8 @@ import io.ktor.serialization.kotlinx.json.json
 import io.ktor.server.application.*
 import io.ktor.server.plugins.*
 import io.ktor.server.plugins.autohead.*
+import io.ktor.server.plugins.callid.CallId
+import io.ktor.server.plugins.callid.callIdMdc
 import io.ktor.server.plugins.calllogging.*
 import io.ktor.server.plugins.compression.*
 import io.ktor.server.plugins.contentnegotiation.*
@@ -16,12 +18,18 @@ import io.ktor.server.plugins.hsts.*
 import io.ktor.server.plugins.partialcontent.*
 import io.ktor.server.request.*
 import io.ktor.server.resources.Resources
+import io.ktor.server.response.respond
 import io.ktor.server.routing.*
 import io.ktor.server.websocket.*
 import kotlin.time.Duration.Companion.seconds
 import kotlin.time.toJavaDuration
+import kotlinx.atomicfu.atomic
 import org.slf4j.event.Level
 
+const val CALL_ID_PREFIX = "trace-id"
+
+private val counter = atomic(1L)
+
 fun Application.configureHTTP() {
   install(Resources)
 
@@ -57,12 +65,28 @@ fun Application.configureHTTP() {
 
   install(HSTS)
 
+  install(CallId) {
+    header(HttpHeaders.XRequestId)
+    generate {
+      when (it.isApi) {
+        true -> "$CALL_ID_PREFIX-${counter.getAndIncrement()}"
+        else -> "$CALL_ID_PREFIX-00000"
+      }
+    }
+    verify { it.isNotEmpty() }
+  }
+
   install(CallLogging) {
     level = Level.INFO
     disableForStaticContent()
     disableDefaultColors()
-    filter { it.isApiRoute }
+
+    // Add MDC entries
     mdc("remoteHost") { call -> call.request.origin.remoteHost }
+    callIdMdc(CALL_ID_PREFIX)
+
+    // Enable logging for API routes only
+    filter { it.isApi }
   }
 
   install(WebSockets) {
@@ -73,8 +97,18 @@ fun Application.configureHTTP() {
   }
 }
 
+fun Application.configureInterceptors() {
+  intercept(ApplicationCallPipeline.Plugins) {
+    println("Request: ${call.request.uri}")
+    if (call.request.headers["Custom-Header"] == "Test") {
+      call.respond(HttpStatusCode.Forbidden)
+      finish()
+    }
+  }
+}
+
 val ApplicationCall.debug
   get() = request.queryParameters.contains("debug")
 
-val ApplicationCall.isApiRoute
-  get() = request.path().startsWith("/api")
+val ApplicationCall.isApi
+  get() = request.path().startsWith("/")

backend/jvm/src/main/kotlin/dev/suresh/plugins/OpenTelemetry.kt

@@ -21,9 +21,7 @@ class TraceIDResponseCustomizer : HttpServerResponseCustomizer {
       responseMutator: HttpServerResponseMutator<T>
   ) {
     val spanContext = Span.fromContextOrNull(serverContext)?.spanContext
-    if (spanContext?.isValid != true) {
-      return
-    }
+    if (spanContext?.isValid != true) return
     responseMutator.appendHeader(response, "X-Trace-Id", spanContext.traceId)
   }
 }

backend/jvm/src/main/resources/logback.xml

@@ -12,7 +12,7 @@
 
     <!-- [%d{ISO8601}] -->
     <property name="pattern"
-              value="%d{YYYY-MM-dd HH:mm:ss.SSS z, America/Los_Angeles} %-5level %X{remoteHost} [%thread] %X{call-id} %logger{16} - %msg%n%rEx"/>
+              value="%d{YYYY-MM-dd HH:mm:ss.SSS z, America/Los_Angeles} %X{trace-id} %-5level %X{remoteHost} [%thread]  %logger{16} - %msg%n%rEx"/>
 
     <appender name="APP1" class="RollingFileAppender">
         <file>${LOG_DIR}/app1.log</file>

gradle/libs.versions.toml

@@ -36,7 +36,7 @@ kotlinx-metadata               = "0.9.0"
 kotlinx-reflect-lite           = "1.1.0"
 kotlinx-bcv                    = "0.16.3"
 kotlin-dokka                   = "1.9.20"
-kotlin-wrappers                = "1.0.0-pre.795"
+kotlin-wrappers                = "1.0.0-pre.797"
 kotlin-redacted                = "1.10.0"
 kotlinx-multik                 = "0.2.3"
 kotlinx-dataframe              = "0.13.1"
@@ -72,7 +72,7 @@ junit                          = "5.11.0"
 koin                           = "3.5.6"
 kotest                         = "5.9.0"
 mockk                          = "1.13.12"
-mokkery                        = "2.2.0"
+mokkery                        = "2.3.0"
 wiremock                       = "3.9.1"
 wiremock-kotlin                = "2.1.1"
 okhttp                         = "5.0.0-alpha.14"

shared/src/commonMain/kotlin/dev/suresh/http/Retry.kt renamed to shared/src/commonMain/kotlin/dev/suresh/http/Config.kt

@@ -2,6 +2,7 @@ package dev.suresh.http
 
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.seconds
+import kotlinx.serialization.Serializable
 
 data class Timeout(val connection: Duration, val read: Duration, val write: Duration) {
   companion object {
@@ -14,3 +15,6 @@ data class Retry(val attempts: Int, val maxDelay: Duration) {
     val DEFAULT = Retry(attempts = 2, maxDelay = 2.seconds)
   }
 }
+
+@Serializable
+data class ErrorStatus(val code: Int, val message: String, val details: String? = null)