[inference] Add cancelation support for chatComplete and output (elas…

…tic#203108)

## Summary

Fix elastic#200757

Add cancelation support for `chatComplete` and `output`, based on an
abort signal.

### Examples

#### response mode

```ts
import { isInferenceRequestAbortedError } from '@kbn/inference-common';

try {
  const abortController = new AbortController();
  const chatResponse = await inferenceClient.chatComplete({
    connectorId: 'some-gen-ai-connector',
    abortSignal: abortController.signal,
    messages: [{ role: MessageRole.User, content: 'Do something' }],
  });
} catch(e) {
  if(isInferenceRequestAbortedError(e)) {
    // request was aborted, do something
  } else {
    // was another error, do something else
  }
}

// elsewhere
abortController.abort()
```

#### stream mode

```ts
import { isInferenceRequestAbortedError } from '@kbn/inference-common';

const abortController = new AbortController();
const events$ = inferenceClient.chatComplete({
  stream: true,
  connectorId: 'some-gen-ai-connector',
  abortSignal: abortController.signal,
  messages: [{ role: MessageRole.User, content: 'Do something' }],
});

events$.subscribe({
  next: (event) => {
    // do something
  },
  error: (err) => {
    if(isInferenceRequestAbortedError(e)) {
      // request was aborted, do something
    } else {
      // was another error, do something else
    }
  }
});

abortController.abort();
```

(cherry picked from commit 0b74f62)

.github/CODEOWNERS

@@ -1423,7 +1423,7 @@ x-pack/test/**/deployment_agnostic/ @elastic/appex-qa #temporarily to monitor te
 #CC# /x-pack/plugins/global_search_providers/ @elastic/kibana-core
 
 # AppEx AI Infra
-/x-pack/plugins/inference @elastic/appex-ai-infra @elastic/obs-ai-assistant @elastic/security-generative-ai
+/x-pack/platform/plugins/shared/inference @elastic/appex-ai-infra @elastic/obs-ai-assistant @elastic/security-generative-ai
 /x-pack/test/functional_gen_ai/inference @elastic/appex-ai-infra
 
 # AppEx Platform Services Security

x-pack/platform/packages/shared/ai-infra/inference-common/index.ts

@@ -84,11 +84,14 @@ export {
   type InferenceTaskErrorEvent,
   type InferenceTaskInternalError,
   type InferenceTaskRequestError,
+  type InferenceTaskAbortedError,
   createInferenceInternalError,
   createInferenceRequestError,
+  createInferenceRequestAbortedError,
   isInferenceError,
   isInferenceInternalError,
   isInferenceRequestError,
+  isInferenceRequestAbortedError,
 } from './src/errors';
 
 export { truncateList } from './src/truncate_list';

x-pack/platform/packages/shared/ai-infra/inference-common/src/chat_complete/api.ts

@@ -93,6 +93,10 @@ export type ChatCompleteOptions<
    * Function calling mode, defaults to "native".
    */
   functionCalling?: FunctionCallingMode;
+  /**
+   * Optional signal that can be used to forcefully abort the request.
+   */
+  abortSignal?: AbortSignal;
 } & TToolOptions;
 
 /**

x-pack/platform/packages/shared/ai-infra/inference-common/src/errors.ts

@@ -13,6 +13,7 @@ import { InferenceTaskEventBase, InferenceTaskEventType } from './inference_task
 export enum InferenceTaskErrorCode {
   internalError = 'internalError',
   requestError = 'requestError',
+  abortedError = 'requestAborted',
 }
 
 /**
@@ -46,16 +47,37 @@ export type InferenceTaskErrorEvent = InferenceTaskEventBase<InferenceTaskEventT
   };
 };
 
+/**
+ * Inference error thrown when an unexpected internal error occurs while handling the request.
+ */
 export type InferenceTaskInternalError = InferenceTaskError<
   InferenceTaskErrorCode.internalError,
   Record<string, any>
 >;
 
+/**
+ * Inference error thrown when the request was considered invalid.
+ *
+ * Some example of reasons for invalid requests would be:
+ * - no connector matching the provided connectorId
+ * - invalid connector type for the provided connectorId
+ */
 export type InferenceTaskRequestError = InferenceTaskError<
   InferenceTaskErrorCode.requestError,
   { status: number }
 >;
 
+/**
+ * Inference error thrown when the request was aborted.
+ *
+ * Request abortion occurs when providing an abort signal and firing it
+ * before the call to the LLM completes.
+ */
+export type InferenceTaskAbortedError = InferenceTaskError<
+  InferenceTaskErrorCode.abortedError,
+  { status: number }
+>;
+
 export function createInferenceInternalError(
   message = 'An internal error occurred',
   meta?: Record<string, any>
@@ -72,16 +94,38 @@ export function createInferenceRequestError(
   });
 }
 
+export function createInferenceRequestAbortedError(): InferenceTaskAbortedError {
+  return new InferenceTaskError(InferenceTaskErrorCode.abortedError, 'Request was aborted', {
+    status: 499,
+  });
+}
+
+/**
+ * Check if the given error is an {@link InferenceTaskError}
+ */
 export function isInferenceError(
   error: unknown
 ): error is InferenceTaskError<string, Record<string, any> | undefined> {
   return error instanceof InferenceTaskError;
 }
 
+/**
+ * Check if the given error is an {@link InferenceTaskInternalError}
+ */
 export function isInferenceInternalError(error: unknown): error is InferenceTaskInternalError {
   return isInferenceError(error) && error.code === InferenceTaskErrorCode.internalError;
 }
 
+/**
+ * Check if the given error is an {@link InferenceTaskRequestError}
+ */
 export function isInferenceRequestError(error: unknown): error is InferenceTaskRequestError {
   return isInferenceError(error) && error.code === InferenceTaskErrorCode.requestError;
 }
+
+/**
+ * Check if the given error is an {@link InferenceTaskAbortedError}
+ */
+export function isInferenceRequestAbortedError(error: unknown): error is InferenceTaskAbortedError {
+  return isInferenceError(error) && error.code === InferenceTaskErrorCode.abortedError;
+}

x-pack/platform/packages/shared/ai-infra/inference-common/src/output/api.ts

@@ -96,7 +96,10 @@ export interface OutputOptions<
    * Defaults to false.
    */
   stream?: TStream;
-
+  /**
+   * Optional signal that can be used to forcefully abort the request.
+   */
+  abortSignal?: AbortSignal;
   /**
    * Optional configuration for retrying the call if an error occurs.
    */

x-pack/platform/plugins/shared/inference/README.md

@@ -221,6 +221,75 @@ const toolCall = toolCalls[0];
 // process the tool call and eventually continue the conversation with the LLM
 ```
 
+#### Request cancellation
+
+Request cancellation can be done by passing an abort signal when calling the API. Firing the signal
+before the request completes will cause the abortion, and the API call will throw an error.
+
+```ts
+const abortController = new AbortController();
+
+const chatResponse = await inferenceClient.chatComplete({
+  connectorId: 'some-gen-ai-connector',
+  abortSignal: abortController.signal,
+  messages: [{ role: MessageRole.User, content: 'Do something' }],
+});
+
+// from elsewhere / before the request completes and the promise resolves:
+
+abortController.abort();
+```
+
+The `isInferenceRequestAbortedError` helper function, exposed from `@kbn/inference-common`, can be used easily identify those errors:
+
+```ts
+import { isInferenceRequestAbortedError } from '@kbn/inference-common';
+
+try {
+  const abortController = new AbortController();
+  const chatResponse = await inferenceClient.chatComplete({
+    connectorId: 'some-gen-ai-connector',
+    abortSignal: abortController.signal,
+    messages: [{ role: MessageRole.User, content: 'Do something' }],
+  });
+} catch(e) {
+  if(isInferenceRequestAbortedError(e)) {
+    // request was aborted, do something
+  } else {
+    // was another error, do something else
+  }
+}
+```
+
+The approach is very similar for stream mode:
+
+```ts
+import { isInferenceRequestAbortedError } from '@kbn/inference-common';
+
+const abortController = new AbortController();
+const events$ = inferenceClient.chatComplete({
+  stream: true,
+  connectorId: 'some-gen-ai-connector',
+  abortSignal: abortController.signal,
+  messages: [{ role: MessageRole.User, content: 'Do something' }],
+});
+
+events$.subscribe({
+  next: (event) => {
+    // do something
+  },
+  error: (err) => {
+    if(isInferenceRequestAbortedError(e)) {
+      // request was aborted, do something
+    } else {
+      // was another error, do something else
+    }
+  }
+});
+
+abortController.abort();
+```
+
 ### `output` API
 
 `output` is a wrapper around the `chatComplete` API that is catered towards a specific use case: having the LLM output a structured response, based on a schema.

x-pack/platform/plugins/shared/inference/common/output/create_output_api.test.ts

@@ -196,4 +196,26 @@ describe('createOutputApi', () => {
       ).toThrowError('Retry options are not supported in streaming mode');
     });
   });
+
+  it('propagates the abort signal when provided', async () => {
+    chatComplete.mockResolvedValue(Promise.resolve({ content: 'content', toolCalls: [] }));
+
+    const output = createOutputApi(chatComplete);
+
+    const abortController = new AbortController();
+
+    await output({
+      id: 'id',
+      connectorId: '.my-connector',
+      input: 'input message',
+      abortSignal: abortController.signal,
+    });
+
+    expect(chatComplete).toHaveBeenCalledTimes(1);
+    expect(chatComplete).toHaveBeenCalledWith(
+      expect.objectContaining({
+        abortSignal: abortController.signal,
+      })
+    );
+  });
 });

x-pack/platform/plugins/shared/inference/common/output/create_output_api.ts

@@ -34,6 +34,7 @@ export function createOutputApi(chatCompleteApi: ChatCompleteAPI) {
     previousMessages,
     functionCalling,
     stream,
+    abortSignal,
     retry,
   }: DefaultOutputOptions): OutputCompositeResponse<string, ToolSchema | undefined, boolean> {
     if (stream && retry !== undefined) {
@@ -52,6 +53,7 @@ export function createOutputApi(chatCompleteApi: ChatCompleteAPI) {
       connectorId,
       stream,
       functionCalling,
+      abortSignal,
       system,
       messages,
       ...(schema
@@ -113,6 +115,7 @@ export function createOutputApi(chatCompleteApi: ChatCompleteAPI) {
               input,
               schema,
               system,
+              abortSignal,
               previousMessages: messages.concat(
                 {
                   role: MessageRole.Assistant as const,

x-pack/platform/plugins/shared/inference/server/chat_complete/adapters/bedrock/bedrock_claude_adapter.test.ts

@@ -325,5 +325,24 @@ describe('bedrockClaudeAdapter', () => {
       expect(tools).toEqual([]);
       expect(system).toEqual(addNoToolUsageDirective('some system instruction'));
     });
+
+    it('propagates the abort signal when provided', () => {
+      const abortController = new AbortController();
+
+      bedrockClaudeAdapter.chatComplete({
+        logger,
+        executor: executorMock,
+        messages: [{ role: MessageRole.User, content: 'question' }],
+        abortSignal: abortController.signal,
+      });
+
+      expect(executorMock.invoke).toHaveBeenCalledTimes(1);
+      expect(executorMock.invoke).toHaveBeenCalledWith({
+        subAction: 'invokeStream',
+        subActionParams: expect.objectContaining({
+          signal: abortController.signal,
+        }),
+      });
+    });
   });
 });

x-pack/platform/plugins/shared/inference/server/chat_complete/adapters/bedrock/bedrock_claude_adapter.ts

@@ -26,7 +26,7 @@ import { processCompletionChunks } from './process_completion_chunks';
 import { addNoToolUsageDirective } from './prompts';
 
 export const bedrockClaudeAdapter: InferenceConnectorAdapter = {
-  chatComplete: ({ executor, system, messages, toolChoice, tools }) => {
+  chatComplete: ({ executor, system, messages, toolChoice, tools, abortSignal }) => {
     const noToolUsage = toolChoice === ToolChoiceType.none;
 
     const subActionParams = {
@@ -36,6 +36,7 @@ export const bedrockClaudeAdapter: InferenceConnectorAdapter = {
       toolChoice: toolChoiceToBedrock(toolChoice),
       temperature: 0,
       stopSequences: ['\n\nHuman:'],
+      signal: abortSignal,
     };
 
     return from(

x-pack/platform/plugins/shared/inference/server/chat_complete/adapters/gemini/gemini_adapter.test.ts

@@ -402,5 +402,24 @@ describe('geminiAdapter', () => {
       expect(tapFn).toHaveBeenCalledWith({ chunk: 1 });
       expect(tapFn).toHaveBeenCalledWith({ chunk: 2 });
     });
+
+    it('propagates the abort signal when provided', () => {
+      const abortController = new AbortController();
+
+      geminiAdapter.chatComplete({
+        logger,
+        executor: executorMock,
+        messages: [{ role: MessageRole.User, content: 'question' }],
+        abortSignal: abortController.signal,
+      });
+
+      expect(executorMock.invoke).toHaveBeenCalledTimes(1);
+      expect(executorMock.invoke).toHaveBeenCalledWith({
+        subAction: 'invokeStream',
+        subActionParams: expect.objectContaining({
+          signal: abortController.signal,
+        }),
+      });
+    });
   });
 });

x-pack/platform/plugins/shared/inference/server/chat_complete/adapters/gemini/gemini_adapter.ts

@@ -22,7 +22,7 @@ import { processVertexStream } from './process_vertex_stream';
 import type { GenerateContentResponseChunk, GeminiMessage, GeminiToolConfig } from './types';
 
 export const geminiAdapter: InferenceConnectorAdapter = {
-  chatComplete: ({ executor, system, messages, toolChoice, tools }) => {
+  chatComplete: ({ executor, system, messages, toolChoice, tools, abortSignal }) => {
     return from(
       executor.invoke({
         subAction: 'invokeStream',
@@ -32,6 +32,7 @@ export const geminiAdapter: InferenceConnectorAdapter = {
           tools: toolsToGemini(tools),
           toolConfig: toolChoiceToConfig(toolChoice),
           temperature: 0,
+          signal: abortSignal,
           stopSequences: ['\n\nHuman:'],
         },
       })

x-pack/platform/plugins/shared/inference/server/chat_complete/adapters/openai/openai_adapter.test.ts

@@ -77,6 +77,7 @@ describe('openAIAdapter', () => {
         };
       });
     });
+
     it('correctly formats messages ', () => {
       openAIAdapter.chatComplete({
         ...defaultArgs,
@@ -254,6 +255,25 @@ describe('openAIAdapter', () => {
       expect(getRequest().stream).toBe(true);
       expect(getRequest().body.stream).toBe(true);
     });
+
+    it('propagates the abort signal when provided', () => {
+      const abortController = new AbortController();
+
+      openAIAdapter.chatComplete({
+        logger,
+        executor: executorMock,
+        messages: [{ role: MessageRole.User, content: 'question' }],
+        abortSignal: abortController.signal,
+      });
+
+      expect(executorMock.invoke).toHaveBeenCalledTimes(1);
+      expect(executorMock.invoke).toHaveBeenCalledWith({
+        subAction: 'stream',
+        subActionParams: expect.objectContaining({
+          signal: abortController.signal,
+        }),
+      });
+    });
   });
 
   describe('when handling the response', () => {