gemini-cli/packages/core/src/services/shellExecutionService.ts

254 lines
8.2 KiB
TypeScript

/**
* @license
* Copyright 2025 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
import { spawn } from 'child_process';
import { TextDecoder } from 'util';
import os from 'os';
import stripAnsi from 'strip-ansi';
import { getCachedEncodingForBuffer } from '../utils/systemEncoding.js';
import { isBinary } from '../utils/textUtils.js';
const SIGKILL_TIMEOUT_MS = 200;
/** A structured result from a shell command execution. */
export interface ShellExecutionResult {
/** The raw, unprocessed output buffer. */
rawOutput: Buffer;
/** The combined, decoded stdout and stderr as a string. */
output: string;
/** The decoded stdout as a string. */
stdout: string;
/** The decoded stderr as a string. */
stderr: string;
/** The process exit code, or null if terminated by a signal. */
exitCode: number | null;
/** The signal that terminated the process, if any. */
signal: NodeJS.Signals | null;
/** An error object if the process failed to spawn. */
error: Error | null;
/** A boolean indicating if the command was aborted by the user. */
aborted: boolean;
/** The process ID of the spawned shell. */
pid: number | undefined;
}
/** A handle for an ongoing shell execution. */
export interface ShellExecutionHandle {
/** The process ID of the spawned shell. */
pid: number | undefined;
/** A promise that resolves with the complete execution result. */
result: Promise<ShellExecutionResult>;
}
/**
* Describes a structured event emitted during shell command execution.
*/
export type ShellOutputEvent =
| {
/** The event contains a chunk of output data. */
type: 'data';
/** The stream from which the data originated. */
stream: 'stdout' | 'stderr';
/** The decoded string chunk. */
chunk: string;
}
| {
/** Signals that the output stream has been identified as binary. */
type: 'binary_detected';
}
| {
/** Provides progress updates for a binary stream. */
type: 'binary_progress';
/** The total number of bytes received so far. */
bytesReceived: number;
};
/**
* A centralized service for executing shell commands with robust process
* management, cross-platform compatibility, and streaming output capabilities.
*
*/
export class ShellExecutionService {
/**
* Executes a shell command using `spawn`, capturing all output and lifecycle events.
*
* @param commandToExecute The exact command string to run.
* @param cwd The working directory to execute the command in.
* @param onOutputEvent A callback for streaming structured events about the execution, including data chunks and status updates.
* @param abortSignal An AbortSignal to terminate the process and its children.
* @returns An object containing the process ID (pid) and a promise that
* resolves with the complete execution result.
*/
static execute(
commandToExecute: string,
cwd: string,
onOutputEvent: (event: ShellOutputEvent) => void,
abortSignal: AbortSignal,
): ShellExecutionHandle {
const isWindows = os.platform() === 'win32';
const child = spawn(commandToExecute, [], {
cwd,
stdio: ['ignore', 'pipe', 'pipe'],
// Use bash unless in Windows (since it doesn't support bash).
// For windows, just use the default.
shell: isWindows ? true : 'bash',
// Use process groups on non-Windows for robust killing.
// Windows process termination is handled by `taskkill /t`.
detached: !isWindows,
env: {
...process.env,
GEMINI_CLI: '1',
},
});
const result = new Promise<ShellExecutionResult>((resolve) => {
// Use decoders to handle multi-byte characters safely (for streaming output).
let stdoutDecoder: TextDecoder | null = null;
let stderrDecoder: TextDecoder | null = null;
let stdout = '';
let stderr = '';
const outputChunks: Buffer[] = [];
let error: Error | null = null;
let exited = false;
let isStreamingRawContent = true;
const MAX_SNIFF_SIZE = 4096;
let sniffedBytes = 0;
const handleOutput = (data: Buffer, stream: 'stdout' | 'stderr') => {
if (!stdoutDecoder || !stderrDecoder) {
const encoding = getCachedEncodingForBuffer(data);
try {
stdoutDecoder = new TextDecoder(encoding);
stderrDecoder = new TextDecoder(encoding);
} catch {
// If the encoding is not supported, fall back to utf-8.
// This can happen on some platforms for certain encodings like 'utf-32le'.
stdoutDecoder = new TextDecoder('utf-8');
stderrDecoder = new TextDecoder('utf-8');
}
}
outputChunks.push(data);
// Binary detection logic. This only runs until we've made a determination.
if (isStreamingRawContent && sniffedBytes < MAX_SNIFF_SIZE) {
const sniffBuffer = Buffer.concat(outputChunks.slice(0, 20));
sniffedBytes = sniffBuffer.length;
if (isBinary(sniffBuffer)) {
// Change state to stop streaming raw content.
isStreamingRawContent = false;
onOutputEvent({ type: 'binary_detected' });
}
}
const decodedChunk =
stream === 'stdout'
? stdoutDecoder.decode(data, { stream: true })
: stderrDecoder.decode(data, { stream: true });
const strippedChunk = stripAnsi(decodedChunk);
if (stream === 'stdout') {
stdout += strippedChunk;
} else {
stderr += strippedChunk;
}
if (isStreamingRawContent) {
onOutputEvent({ type: 'data', stream, chunk: strippedChunk });
} else {
const totalBytes = outputChunks.reduce(
(sum, chunk) => sum + chunk.length,
0,
);
onOutputEvent({ type: 'binary_progress', bytesReceived: totalBytes });
}
};
child.stdout.on('data', (data) => handleOutput(data, 'stdout'));
child.stderr.on('data', (data) => handleOutput(data, 'stderr'));
child.on('error', (err) => {
const { stdout, stderr, finalBuffer } = cleanup();
error = err;
resolve({
error,
stdout,
stderr,
rawOutput: finalBuffer,
output: stdout + (stderr ? `\n${stderr}` : ''),
exitCode: 1,
signal: null,
aborted: false,
pid: child.pid,
});
});
const abortHandler = async () => {
if (child.pid && !exited) {
if (isWindows) {
spawn('taskkill', ['/pid', child.pid.toString(), '/f', '/t']);
} else {
try {
// Kill the entire process group (negative PID).
// SIGTERM first, then SIGKILL if it doesn't die.
process.kill(-child.pid, 'SIGTERM');
await new Promise((res) => setTimeout(res, SIGKILL_TIMEOUT_MS));
if (!exited) {
process.kill(-child.pid, 'SIGKILL');
}
} catch (_e) {
// Fall back to killing just the main process if group kill fails.
if (!exited) child.kill('SIGKILL');
}
}
}
};
abortSignal.addEventListener('abort', abortHandler, { once: true });
child.on('exit', (code: number, signal: NodeJS.Signals) => {
const { stdout, stderr, finalBuffer } = cleanup();
resolve({
rawOutput: finalBuffer,
output: stdout + (stderr ? `\n${stderr}` : ''),
stdout,
stderr,
exitCode: code,
signal,
error,
aborted: abortSignal.aborted,
pid: child.pid,
});
});
/**
* Cleans up a process (and it's accompanying state) that is exiting or
* erroring and returns output formatted output buffers and strings
*/
function cleanup() {
exited = true;
abortSignal.removeEventListener('abort', abortHandler);
if (stdoutDecoder) {
stdout += stripAnsi(stdoutDecoder.decode());
}
if (stderrDecoder) {
stderr += stripAnsi(stderrDecoder.decode());
}
const finalBuffer = Buffer.concat(outputChunks);
return { stdout, stderr, finalBuffer };
}
});
return { pid: child.pid, result };
}
}