Improve DeepSeek request failure handling

.vscode/settings.json

@@ -1,5 +1,5 @@
 {
-  "typescript.tsdk": "node_modules/typescript/lib",
+  "js/ts.tsdk.path": "node_modules/typescript/lib",
   "editor.codeActionsOnSave": {
     "source.organizeImports": "explicit"
   }

package.json

@@ -35,6 +35,7 @@
     "chat"
   ],
   "activationEvents": [
+    "onUri",
     "onStartupFinished"
   ],
   "enabledApiProposals": [],

src/client/consts.ts

@@ -0,0 +1,123 @@
+import type {
+	ApiProviderId,
+	HttpErrorLinkDefinition,
+	HttpErrorLinkStatusKey,
+	NetworkErrorCategory,
+} from './types';
+import { EXTERNAL_URLS } from '../consts';
+
+export const OFFICIAL_DEEPSEEK_API_HOST = 'api.deepseek.com';
+export const MAX_DIAGNOSTIC_FIELD_LENGTH = 300;
+
+export const API_PROVIDER_HTTP_ERROR_LINKS: Readonly<
+	Record<HttpErrorLinkStatusKey, Readonly<Partial<Record<ApiProviderId, HttpErrorLinkDefinition>>>>
+> = {
+	401: {
+		deepseek: {
+			labelKey: 'error.action.createApiKey',
+			url: EXTERNAL_URLS.deepseek.apiKeys,
+		},
+	},
+	402: {
+		deepseek: {
+			labelKey: 'error.action.viewUsage',
+			url: EXTERNAL_URLS.deepseek.usage,
+		},
+	},
+	'5xx': {
+		deepseek: {
+			labelKey: 'error.action.checkDeepSeekStatus',
+			url: EXTERNAL_URLS.deepseek.status,
+		},
+	},
+};
+
+/**
+ * Curated network error codes observed from Node.js fetch failures.
+ *
+ * Sources: Node errno / c-ares DNS codes (`NodeJS.ErrnoException.code`),
+ * Node TLS/OpenSSL error codes, and undici error `code` / `name` literals
+ * from the `undici-types` package bundled through `@types/node`.
+ *
+ * This is intentionally not exhaustive: unknown codes fall back to `generic`
+ * while still being shown to the user in the error message.
+ */
+export const NETWORK_ERROR_CATEGORY_BY_CODE = {
+	ENOTFOUND: 'dns',
+	EAI_AGAIN: 'dns',
+	ENODATA: 'dns',
+	ESERVFAIL: 'dns',
+	EFORMERR: 'dns',
+	ENONAME: 'dns',
+	EBADNAME: 'dns',
+	EBADQUERY: 'dns',
+	EBADFAMILY: 'dns',
+	EBADRESP: 'dns',
+	ENOTIMP: 'dns',
+	EREFUSED: 'dns',
+	ENOTINITIALIZED: 'dns',
+	ELOADIPHLPAPI: 'dns',
+	EADDRGETNETWORKPARAMS: 'dns',
+	ECONNREFUSED: 'unreachable',
+	ENETUNREACH: 'unreachable',
+	EHOSTUNREACH: 'unreachable',
+	EADDRNOTAVAIL: 'unreachable',
+	ENETDOWN: 'unreachable',
+	EHOSTDOWN: 'unreachable',
+	ECONNRESET: 'interrupted',
+	ECONNABORTED: 'interrupted',
+	ENETRESET: 'interrupted',
+	ENOTCONN: 'interrupted',
+	EPIPE: 'interrupted',
+	EOF: 'interrupted',
+	UND_ERR_SOCKET: 'interrupted',
+	SocketError: 'interrupted',
+	ETIMEDOUT: 'timeout',
+	ETIMEOUT: 'timeout',
+	ESOCKETTIMEDOUT: 'timeout',
+	UND_ERR_CONNECT_TIMEOUT: 'timeout',
+	UND_ERR_HEADERS_TIMEOUT: 'timeout',
+	UND_ERR_BODY_TIMEOUT: 'timeout',
+	ERR_TLS_HANDSHAKE_TIMEOUT: 'timeout',
+	TimeoutError: 'timeout',
+	ConnectTimeoutError: 'timeout',
+	HeadersTimeoutError: 'timeout',
+	BodyTimeoutError: 'timeout',
+	CERT_HAS_EXPIRED: 'tls',
+	CERT_NOT_YET_VALID: 'tls',
+	CERT_UNTRUSTED: 'tls',
+	CERT_REJECTED: 'tls',
+	CERT_SIGNATURE_FAILURE: 'tls',
+	SELF_SIGNED_CERT_IN_CHAIN: 'tls',
+	DEPTH_ZERO_SELF_SIGNED_CERT: 'tls',
+	UNABLE_TO_VERIFY_LEAF_SIGNATURE: 'tls',
+	UNABLE_TO_GET_ISSUER_CERT_LOCALLY: 'tls',
+	UNABLE_TO_GET_ISSUER_CERT: 'tls',
+	UNABLE_TO_GET_CRL: 'tls',
+	UNABLE_TO_DECRYPT_CERT_SIGNATURE: 'tls',
+	UNABLE_TO_DECRYPT_CRL_SIGNATURE: 'tls',
+	UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY: 'tls',
+	CRL_SIGNATURE_FAILURE: 'tls',
+	ERR_TLS_CERT_ALTNAME_INVALID: 'tls',
+	UND_ERR_PRX_TLS: 'tls',
+	SecureProxyConnectionError: 'tls',
+	ABORT_ERR: 'aborted',
+	AbortError: 'aborted',
+	UND_ERR_ABORTED: 'aborted',
+	ECANCELLED: 'aborted',
+	UND_ERR_HEADERS_OVERFLOW: 'protocol',
+	UND_ERR_RESPONSE: 'protocol',
+	UND_ERR_REQ_CONTENT_LENGTH_MISMATCH: 'protocol',
+	UND_ERR_RES_CONTENT_LENGTH_MISMATCH: 'protocol',
+	UND_ERR_RES_EXCEEDED_MAX_SIZE: 'protocol',
+	HTTPParserError: 'protocol',
+	HeadersOverflowError: 'protocol',
+	ResponseError: 'protocol',
+	ResponseContentLengthMismatchError: 'protocol',
+	ResponseExceededMaxSizeError: 'protocol',
+	ERR_INVALID_URL: 'configuration',
+	ERR_INVALID_ARG_TYPE: 'configuration',
+	ERR_INVALID_ARG_VALUE: 'configuration',
+	UND_ERR_INVALID_ARG: 'configuration',
+	InvalidArgumentError: 'configuration',
+} as const satisfies Record<string, NetworkErrorCategory>;

src/client.ts → src/client/core.ts

@@ -1,12 +1,13 @@
 import type { CancellationToken } from 'vscode';
-import { safeStringify } from './json';
-import { logger } from './logger';
+import { safeStringify } from '../json';
+import { logger } from '../logger';
 import type {
 	DeepSeekRequest,
 	DeepSeekStreamChunk,
 	DeepSeekToolCall,
 	StreamCallbacks,
-} from './types';
+} from '../types';
+import { createHttpError, normalizeRequestError } from './error';
 
 /**
  * Lightweight SSE-streaming DeepSeek API client.
@@ -53,15 +54,7 @@ export class DeepSeekClient {
 			});
 
 			if (!response.ok) {
-				const errorText = await response.text();
-				let errorMessage: string;
-				try {
-					const errorJson = JSON.parse(errorText);
-					errorMessage = errorJson.error?.message || errorJson.message || errorText;
-				} catch {
-					errorMessage = errorText;
-				}
-				throw new Error(`DeepSeek API error (${response.status}): ${errorMessage}`);
+				throw await createHttpError(response, this.baseUrl);
 			}
 
 			if (!response.body) {
@@ -178,7 +171,9 @@ export class DeepSeekClient {
 			if (isAbortError(error) && cancellationToken?.isCancellationRequested) {
 				return;
 			}
-			callbacks.onError(error instanceof Error ? error : new Error(String(error)));
+			const normalizedError = normalizeRequestError(error);
+			logger.error('DeepSeek request failed:', getDiagnosticMessage(normalizedError), error);
+			callbacks.onError(normalizedError);
 		} finally {
 			cancelListener?.dispose();
 		}
@@ -188,3 +183,9 @@ export class DeepSeekClient {
 function isAbortError(error: unknown): boolean {
 	return error instanceof Error && error.name === 'AbortError';
 }
+
+function getDiagnosticMessage(error: Error): string {
+	return 'diagnosticMessage' in error && typeof error.diagnosticMessage === 'string'
+		? error.diagnosticMessage
+		: error.message;
+}