Add Micrometer integration to ktor client

build.gradle.kts

@@ -11,7 +11,7 @@ plugins {
 }
 
 group = "eu.kevin"
-version = "0.2.7"
+version = "0.2.9"
 
 repositories {
     mavenCentral()
@@ -22,6 +22,7 @@ dependencies {
     implementation("io.ktor:ktor-client-core:${Versions.KTOR}")
     implementation("io.ktor:ktor-client-cio:${Versions.KTOR}")
     implementation("io.ktor:ktor-client-serialization:${Versions.KTOR}")
+    implementation("io.micrometer:micrometer-registry-prometheus:${Versions.MICROMETER}")
 
     testImplementation(kotlin("test"))
     testImplementation("io.ktor:ktor-client-mock:${Versions.KTOR}")

buildSrc/src/main/kotlin/Dependencies.kt

@@ -3,4 +3,5 @@ object Versions {
     const val KTOR = "1.6.5"
     const val KTLINT = "10.2.0"
     const val NEXUS_PUBLISH = "1.1.0"
+    const val MICROMETER = "1.9.1"
 }

src/main/kotlin/eu/kevin/api/models/ErrorCode.kt

@@ -24,7 +24,7 @@ enum class ErrorCode(val code: Int) {
     @SerialName("20016") INVALID_DEBTOR_ACCOUNT(20016),
     @SerialName("20017") INSUFFICIENT_FUNDS(20017),
     @SerialName("20020") CHOSEN_SCA_METHOD_REQUIRE_VALID_PSU_PERSON_ID(20020),
-    @SerialName("20017") CHOSEN_SCA_METHOD_REQUIRE_VALID_PSU_PHONE_NUMBER(20021),
+    @SerialName("20021") CHOSEN_SCA_METHOD_REQUIRE_VALID_PSU_PHONE_NUMBER(20021),
     @SerialName("20022") CREDITOR_ACCOUNT_NUMBER_INVALID_OR_MISSING(20022),
     @SerialName("20023") THE_ACCOUNT_NUMBER_AND_THE_NAME_DO_NOT_COINCIDE(20023),
     @SerialName("20024") TRANSACTION_CURRENCY_IS_INVALID_OR_MISSING(20024),

src/main/kotlin/eu/kevin/api/plugins/KtorClientMicrometerMetrics.kt

@@ -0,0 +1,99 @@
+package eu.kevin.api.plugins
+
+import io.ktor.client.*
+import io.ktor.client.features.*
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.client.utils.*
+import io.ktor.http.*
+import io.ktor.util.*
+import io.ktor.util.pipeline.*
+import io.micrometer.core.instrument.MeterRegistry
+import io.micrometer.core.instrument.Tag
+import io.micrometer.core.instrument.Tags
+import io.micrometer.core.instrument.Timer
+import java.net.URLDecoder
+import java.nio.charset.StandardCharsets
+
+/**
+ * Feature to get statistics from KTor client. Partially lifted off https://youtrack.jetbrains.com/issue/KTOR-1004
+ */
+class KtorClientMicrometerMetrics internal constructor(val meterRegistry: MeterRegistry) {
+    private fun stopTimer(sample: Timer.Sample, url: Url, path: String, method: String, status: Int, throwable: Throwable?) {
+        val parameters = mutableMapOf(
+            "host" to url.host,
+            "path" to path,
+            "method" to method,
+            "status" to status.toString()
+        )
+
+        throwable?.let {
+            parameters["throwable"] = it.javaClass.simpleName
+        }
+
+        sample.stop(
+            meterRegistry.timer(
+                "http.client.requests",
+                Tags.of((parameters).map { Tag.of(it.key, it.value) })
+            )
+        )
+    }
+
+    class Config {
+        lateinit var meterRegistry: MeterRegistry
+    }
+
+    companion object Feature : HttpClientFeature<Config, KtorClientMicrometerMetrics> {
+        override val key: AttributeKey<KtorClientMicrometerMetrics> = AttributeKey("ClientMetrics")
+
+        val pathAttributeKey: AttributeKey<String> = AttributeKey("Path")
+        private val sampleAttributeKey: AttributeKey<Timer.Sample> = AttributeKey("TimerSample")
+        private val monitoringPhase = PipelinePhase("Monitoring")
+
+        override fun prepare(block: Config.() -> Unit): KtorClientMicrometerMetrics {
+            val config = Config().apply(block)
+            return KtorClientMicrometerMetrics(config.meterRegistry)
+        }
+
+        @OptIn(InternalAPI::class)
+        override fun install(plugin: KtorClientMicrometerMetrics, scope: HttpClient) {
+            scope.receivePipeline.insertPhaseAfter(HttpReceivePipeline.Before, monitoringPhase)
+
+            scope.sendPipeline.intercept(HttpSendPipeline.Monitoring) {
+                val sample = Timer.start(plugin.meterRegistry)
+                try {
+                    context.attributes.put(sampleAttributeKey, sample)
+                    proceed()
+                } catch (cause: Throwable) {
+                    val url = context.url.build()
+
+                    plugin.stopTimer(
+                        sample = sample,
+                        url = url,
+                        path = context.attributes.getOrNull(pathAttributeKey)
+                            ?: URLDecoder.decode(url.encodedPath, StandardCharsets.UTF_8),
+                        method = context.method.value,
+                        status = 500,
+                        throwable = cause
+                    )
+                    throw cause.unwrapCancellationException()
+                }
+            }
+
+            scope.receivePipeline.intercept(monitoringPhase) {
+                val url = it.call.request.url
+
+                plugin.stopTimer(
+                    sample = it.request.attributes[sampleAttributeKey],
+                    url = url,
+                    path = it.request.attributes.getOrNull(pathAttributeKey)
+                        ?: URLDecoder.decode(url.encodedPath, StandardCharsets.UTF_8),
+                    method = it.request.method.value,
+                    status = it.call.response.status.value,
+                    throwable = null
+                )
+                proceed()
+            }
+        }
+    }
+}

src/main/kotlin/eu/kevin/api/services/Client.kt

@@ -3,6 +3,7 @@ package eu.kevin.api.services
 import eu.kevin.api.Dependencies
 import eu.kevin.api.Endpoint
 import eu.kevin.api.models.Authorization
+import eu.kevin.api.plugins.KtorClientMicrometerMetrics
 import eu.kevin.api.services.account.AccountClient
 import eu.kevin.api.services.auth.AuthClient
 import eu.kevin.api.services.general.GeneralClient
@@ -11,31 +12,32 @@ import io.ktor.client.*
 import io.ktor.client.features.*
 import io.ktor.client.request.*
 import io.ktor.http.*
-import kotlinx.serialization.json.Json
+import io.micrometer.core.instrument.MeterRegistry
 import java.net.URI
 
 class Client internal constructor(
     private val authorization: Authorization,
     private val apiUrl: String,
     private val httpClient: HttpClient,
-    private val serializer: Json,
-    private val customHeaders: Map<String, String>
+    private val customHeaders: Map<String, String>,
+    private val micrometerRegistry: MeterRegistry?
 ) {
     val paymentClient by lazy { PaymentClient(httpClient = httpClient.withAuthorization()) }
     val authClient by lazy { AuthClient(httpClient = httpClient.withAuthorization()) }
     val generalClient by lazy { GeneralClient(httpClient = httpClient.withAuthorization()) }
-    val accountClient by lazy { AccountClient(httpClient = httpClient.withAuthorization(), serializer = serializer) }
+    val accountClient by lazy { AccountClient(httpClient = httpClient.withAuthorization()) }
 
     constructor(
         authorization: Authorization,
         apiUrl: String = Endpoint.BASE,
-        customHeaders: Map<String, String> = mapOf()
+        customHeaders: Map<String, String> = mapOf(),
+        micrometerRegistry: MeterRegistry? = null
     ) : this(
         authorization = authorization,
         apiUrl = apiUrl,
         httpClient = Dependencies.httpClient,
-        serializer = Dependencies.serializer,
-        customHeaders = customHeaders
+        customHeaders = customHeaders,
+        micrometerRegistry = micrometerRegistry
     )
 
     private fun HttpClient.withAuthorization() = this.config {
@@ -51,5 +53,10 @@ class Client internal constructor(
             header("Client-Secret", authorization.clientSecret)
             customHeaders.forEach { header(it.key, it.value) }
         }
+        if (micrometerRegistry != null) {
+            install(KtorClientMicrometerMetrics) {
+                meterRegistry = micrometerRegistry
+            }
+        }
     }
 }

src/main/kotlin/eu/kevin/api/services/account/AccountClient.kt

@@ -12,16 +12,16 @@ import eu.kevin.api.models.account.detail.GetAccountDetailsRequest
 import eu.kevin.api.models.account.list.AccountResponse
 import eu.kevin.api.models.account.transaction.request.GetAccountTransactionsRequest
 import eu.kevin.api.models.account.transaction.response.AccountTransactionResponse
+import eu.kevin.api.plugins.KtorClientMicrometerMetrics
 import io.ktor.client.*
 import io.ktor.client.request.*
-import kotlinx.serialization.json.Json
+import io.ktor.util.*
 
 /**
  * Implements API Methods of the [Account information service](https://docs.kevin.eu/public/platform/v0.3#tag/Account-Information-Service)
  */
 class AccountClient internal constructor(
-    private val httpClient: HttpClient,
-    private val serializer: Json
+    private val httpClient: HttpClient
 ) {
 
     /**
@@ -33,6 +33,7 @@ class AccountClient internal constructor(
             path = Endpoint.Paths.Account.getAccountsList()
         ) {
             appendAccountRequestHeaders(headers = request)
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Account.getAccountsList())
         }.data
 
     /**
@@ -44,6 +45,7 @@ class AccountClient internal constructor(
             path = Endpoint.Paths.Account.getAccountDetails(accountId = request.accountId)
         ) {
             appendAccountRequestHeaders(headers = request.headers)
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Account.getAccountDetails("$"))
         }
 
     /**
@@ -57,6 +59,7 @@ class AccountClient internal constructor(
             appendAccountRequestHeaders(headers = request.headers)
             parameter("dateFrom", request.dateFrom)
             parameter("dateTo", request.dateTo)
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Account.getAccountTransactions("$"))
         }.data
 
     /**
@@ -68,6 +71,7 @@ class AccountClient internal constructor(
             path = Endpoint.Paths.Account.getAccountBalance(accountId = request.accountId)
         ) {
             appendAccountRequestHeaders(headers = request.headers)
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Account.getAccountBalance("$"))
         }.data
 
     private fun HttpRequestBuilder.appendAccountRequestHeaders(headers: AccountRequestHeaders) {

src/main/kotlin/eu/kevin/api/services/auth/AuthClient.kt

@@ -12,6 +12,7 @@ import eu.kevin.api.models.auth.token.request.RefreshTokenRequest
 import eu.kevin.api.models.auth.token.response.ReceiveTokenResponse
 import eu.kevin.api.models.auth.tokenContent.ReceiveTokenContentRequest
 import eu.kevin.api.models.auth.tokenContent.ReceiveTokenContentResponse
+import eu.kevin.api.plugins.KtorClientMicrometerMetrics
 import io.ktor.client.*
 import io.ktor.client.request.*
 import io.ktor.http.*
@@ -47,6 +48,7 @@ class AuthClient internal constructor(
                     webhookUrl?.let { append("Webhook-URL", it) }
                 }
             }
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Auth.startAuthentication())
         }.run {
             copy(
                 authorizationLink = Url(authorizationLink)
@@ -63,7 +65,9 @@ class AuthClient internal constructor(
         httpClient.post(
             path = Endpoint.Paths.Auth.receiveToken(),
             body = request
-        )
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Auth.receiveToken())
+        }
 
     /**
      * API Method: [Receive token](https://docs.kevin.eu/public/platform/v0.3#operation/receiveToken), with `grantType` set to `refreshToken`
@@ -73,7 +77,9 @@ class AuthClient internal constructor(
         httpClient.post(
             path = Endpoint.Paths.Auth.receiveToken(),
             body = request
-        )
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Auth.receiveToken())
+        }
 
     /**
      * API Method: [Receive token content](https://docs.kevin.eu/public/platform/v0.3#operation/receiveTokenContent)
@@ -86,5 +92,6 @@ class AuthClient internal constructor(
             headers {
                 append(HttpHeaders.Authorization, request.accessToken.appendAtStartIfNotExist("Bearer "))
             }
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Auth.receiveTokenContent())
         }
 }

src/main/kotlin/eu/kevin/api/services/general/GeneralClient.kt

@@ -5,6 +5,7 @@ import eu.kevin.api.exceptions.KevinApiErrorException
 import eu.kevin.api.models.ResponseArray
 import eu.kevin.api.models.general.bank.BankResponse
 import eu.kevin.api.models.general.projectSettings.GetProjectSettingsResponse
+import eu.kevin.api.plugins.KtorClientMicrometerMetrics
 import io.ktor.client.*
 import io.ktor.client.request.*
 
@@ -21,7 +22,9 @@ class GeneralClient internal constructor(
     suspend fun getSupportedCountries(): List<String> =
         httpClient.get<ResponseArray<String>>(
             path = Endpoint.Paths.General.getSupportedCountries()
-        ).data
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.General.getSupportedCountries())
+        }.data
 
     /**
      * API Method: [Get supported banks](https://docs.kevin.eu/public/platform/v0.3#operation/getBanks)
@@ -33,6 +36,7 @@ class GeneralClient internal constructor(
             path = Endpoint.Paths.General.getSupportedBanks()
         ) {
             parameter("countryCode", countryCode)
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.General.getSupportedBanks())
         }.data
 
     /**
@@ -42,7 +46,9 @@ class GeneralClient internal constructor(
     suspend fun getSupportedBank(bankId: String): BankResponse =
         httpClient.get(
             path = Endpoint.Paths.General.getSupportedBank(bankId = bankId)
-        )
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.General.getSupportedBank("$"))
+        }
 
     /**
      * API Method: [Get supported bank by card number piece](https://docs.kevin.eu/public/platform/v0.3#operation/getBankByCardNumberPiece)
@@ -51,7 +57,9 @@ class GeneralClient internal constructor(
     suspend fun getSupportedBankByCardNumberPiece(cardNumberPiece: String): BankResponse =
         httpClient.get(
             path = Endpoint.Paths.General.getSupportedBankByCardNumberPiece(cardNumberPiece = cardNumberPiece)
-        )
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.General.getSupportedBankByCardNumberPiece("$"))
+        }
 
     /**
      * API Method: [Get payment methods](https://docs.kevin.eu/public/platform/v0.3#operation/getPaymentMethods)
@@ -60,7 +68,9 @@ class GeneralClient internal constructor(
     suspend fun getPaymentMethods(): List<String> =
         httpClient.get<ResponseArray<String>>(
             path = Endpoint.Paths.General.getPaymentMethods()
-        ).data
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.General.getPaymentMethods())
+        }.data
 
     /**
      * API Method: [Get project settings](https://docs.kevin.eu/public/platform/v0.3#operation/getProjectSettings)
@@ -69,5 +79,7 @@ class GeneralClient internal constructor(
     suspend fun getProjectSettings(): GetProjectSettingsResponse =
         httpClient.get(
             path = Endpoint.Paths.General.getProjectSettings()
-        )
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.General.getProjectSettings())
+        }
 }

src/main/kotlin/eu/kevin/api/services/payment/PaymentClient.kt

@@ -12,6 +12,7 @@ import eu.kevin.api.models.payment.paymentStatus.GetPaymentStatusResponse
 import eu.kevin.api.models.payment.refund.InitiatePaymentRefundRequest
 import eu.kevin.api.models.payment.refund.InitiatePaymentRefundRequestBody
 import eu.kevin.api.models.payment.refund.InitiatePaymentRefundResponse
+import eu.kevin.api.plugins.KtorClientMicrometerMetrics
 import io.ktor.client.*
 import io.ktor.client.request.*
 import io.ktor.http.*
@@ -51,6 +52,7 @@ class PaymentClient internal constructor(
                     webhookUrl?.let { append("Webhook-URL", it) }
                 }
             }
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Payment.initiatePayment())
         }.run {
             copy(
                 confirmLink = confirmLink?.let {
@@ -66,7 +68,9 @@ class PaymentClient internal constructor(
     suspend fun getPaymentStatus(request: GetPaymentStatusRequest): GetPaymentStatusResponse =
         httpClient.get(
             path = Endpoint.Paths.Payment.getPaymentStatus(paymentId = request.paymentId)
-        )
+        ) {
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Payment.getPaymentStatus("$"))
+        }
 
     /**
      * API Method: [Initiate payment refund](https://docs.kevin.eu/public/platform/v0.3#operation/initiatePaymentRefund)
@@ -82,5 +86,6 @@ class PaymentClient internal constructor(
                     webhookUrl?.let { append("Webhook-URL", it) }
                 }
             }
+            attributes.put(KtorClientMicrometerMetrics.pathAttributeKey, Endpoint.Paths.Payment.initiatePaymentRefund("$"))
         }
 }