Fix error messages (#102)

Author: jacoblee93

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/BadRequestException.kt

@@ -10,7 +10,7 @@ import kotlin.jvm.optionals.getOrNull
 
 class BadRequestException
 private constructor(private val headers: Headers, private val body: JsonValue, cause: Throwable?) :
-    LangChainServiceException("400: $body", cause) {
+    LangChainServiceException(formatMessage(400, body), cause) {
 
     override fun statusCode(): Int = 400
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/InternalServerException.kt

@@ -14,7 +14,7 @@ private constructor(
     private val headers: Headers,
     private val body: JsonValue,
     cause: Throwable?,
-) : LangChainServiceException("$statusCode: $body", cause) {
+) : LangChainServiceException(formatMessage(statusCode, body), cause) {
 
     override fun statusCode(): Int = statusCode
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/LangChainServiceException.kt

@@ -2,6 +2,7 @@
 
 package com.langchain.smith.errors
 
+import com.fasterxml.jackson.databind.ObjectMapper
 import com.langchain.smith.core.JsonValue
 import com.langchain.smith.core.http.Headers
 
@@ -14,4 +15,19 @@ protected constructor(message: String, cause: Throwable? = null) :
     abstract fun headers(): Headers
 
     abstract fun body(): JsonValue
+
+    companion object {
+
+        /** Formats a status code and [JsonValue] error body into an error message. */
+        @JvmStatic
+        fun formatMessage(statusCode: Int, body: JsonValue): String {
+            val bodyStr =
+                try {
+                    ObjectMapper().writeValueAsString(body)
+                } catch (_: Exception) {
+                    body.toString()
+                }
+            return "$statusCode: $bodyStr"
+        }
+    }
 }

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/NotFoundException.kt

@@ -10,7 +10,7 @@ import kotlin.jvm.optionals.getOrNull
 
 class NotFoundException
 private constructor(private val headers: Headers, private val body: JsonValue, cause: Throwable?) :
-    LangChainServiceException("404: $body", cause) {
+    LangChainServiceException(formatMessage(404, body), cause) {
 
     override fun statusCode(): Int = 404
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/PermissionDeniedException.kt

@@ -10,7 +10,7 @@ import kotlin.jvm.optionals.getOrNull
 
 class PermissionDeniedException
 private constructor(private val headers: Headers, private val body: JsonValue, cause: Throwable?) :
-    LangChainServiceException("403: $body", cause) {
+    LangChainServiceException(formatMessage(403, body), cause) {
 
     override fun statusCode(): Int = 403
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/RateLimitException.kt

@@ -10,7 +10,7 @@ import kotlin.jvm.optionals.getOrNull
 
 class RateLimitException
 private constructor(private val headers: Headers, private val body: JsonValue, cause: Throwable?) :
-    LangChainServiceException("429: $body", cause) {
+    LangChainServiceException(formatMessage(429, body), cause) {
 
     override fun statusCode(): Int = 429
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/UnauthorizedException.kt

@@ -10,7 +10,7 @@ import kotlin.jvm.optionals.getOrNull
 
 class UnauthorizedException
 private constructor(private val headers: Headers, private val body: JsonValue, cause: Throwable?) :
-    LangChainServiceException("401: $body", cause) {
+    LangChainServiceException(formatMessage(401, body), cause) {
 
     override fun statusCode(): Int = 401
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/UnexpectedStatusCodeException.kt

@@ -14,7 +14,7 @@ private constructor(
     private val headers: Headers,
     private val body: JsonValue,
     cause: Throwable?,
-) : LangChainServiceException("$statusCode: $body", cause) {
+) : LangChainServiceException(formatMessage(statusCode, body), cause) {
 
     override fun statusCode(): Int = statusCode
 

langsmith-java-core/src/main/kotlin/com/langchain/smith/errors/UnprocessableEntityException.kt

@@ -10,7 +10,7 @@ import kotlin.jvm.optionals.getOrNull
 
 class UnprocessableEntityException
 private constructor(private val headers: Headers, private val body: JsonValue, cause: Throwable?) :
-    LangChainServiceException("422: $body", cause) {
+    LangChainServiceException(formatMessage(422, body), cause) {
 
     override fun statusCode(): Int = 422
 

langsmith-java-core/src/test/kotlin/com/langchain/smith/errors/ServiceExceptionErrorMessageTest.kt

@@ -0,0 +1,60 @@
+package com.langchain.smith.errors
+
+import com.langchain.smith.client.okhttp.LangsmithOkHttpClient
+import com.langchain.smith.models.runs.Run
+import com.langchain.smith.models.runs.RunIngestBatchParams
+import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.assertThatThrownBy
+import org.junit.jupiter.api.Assumptions.assumeTrue
+import org.junit.jupiter.api.Test
+
+/**
+ * Verifies that service exception error messages contain the actual API error body rather than
+ * opaque strings like `[object Object]`.
+ *
+ * Run with:
+ * ```bash
+ * ./gradlew :langsmith-java-core:test --tests "com.langchain.smith.errors.ServiceExceptionErrorMessageTest"
+ * ```
+ */
+internal class ServiceExceptionErrorMessageTest {
+
+    @Test
+    fun forbiddenErrorContainsDetail() {
+        val client = LangsmithOkHttpClient.builder().apiKey("ls-invalid-key").build()
+
+        assertThatThrownBy { client.runs().ingestBatch() }
+            .isInstanceOf(PermissionDeniedException::class.java)
+            .satisfies({ e ->
+                val message = e.message ?: ""
+                assertThat(message).startsWith("403:")
+                assertThat(message).doesNotContain("[object Object]")
+                assertThat(message).contains("Forbidden")
+            })
+    }
+
+    @Test
+    fun badRequestErrorContainsDetail() {
+        assumeTrue(
+            !System.getenv("LANGSMITH_API_KEY").isNullOrBlank(),
+            "Skipping: LANGSMITH_API_KEY must be set",
+        )
+        val client = LangsmithOkHttpClient.fromEnv()
+
+        val params =
+            RunIngestBatchParams.builder()
+                .addPost(
+                    Run.builder().id("not-a-uuid").name("test").runType(Run.RunType.CHAIN).build()
+                )
+                .build()
+
+        assertThatThrownBy { client.runs().ingestBatch(params) }
+            .isInstanceOf(UnprocessableEntityException::class.java)
+            .satisfies({ e ->
+                val message = e.message ?: ""
+                assertThat(message).startsWith("422:")
+                assertThat(message).doesNotContain("[object Object]")
+                assertThat(message).contains("error")
+            })
+    }
+}