feat(instance): 为 instance exec 命令添加 --shell 和 --workdir 参数

- 新增 --shell 参数：支持指定使用的 shell（如 /bin/sh, /bin/bash），解决 Alpine 等镜像只有 sh 的问题
- 新增 --workdir 参数：支持自定义初始工作目录，解决默认强制进入 /code 目录的问题
- 新增 --no-workdir 参数：不 cd 到任何目录，直接使用容器的 WORKDIR
- 保持完全向后兼容：不传参数时行为与之前完全一致

问题背景：
1. 当前 instance exec 硬编码使用 bash，导致只有 sh 的镜像（如 Alpine）无法使用
2. 默认强制尝试进入 /code 目录，对于使用其他工作目录的容器不够灵活

解决方案：
1. --shell 参数允许用户指定 shell 类型，默认值为 bash
2. --workdir 参数支持三种模式：
   - 不指定：默认行为，尝试 cd /code || cd /
   - 指定路径：cd 到指定目录
   - 空字符串或 --no-workdir：不执行 cd，直接使用容器默认 WORKDIR

Signed-off-by: hugh.li <hugh.li@foxmail.com>

Author: hughcube

src/commands-help/instance.ts

@@ -10,10 +10,16 @@ export default {
 Examples with Yaml:
   $ s instance exec --instance-id c-6******-27c4833c325445879a28 --cmd "ls -lh"
   $ s instance exec --instance-id c-6******-27c4833c325445879a28
+  $ s instance exec --instance-id c-6******-27c4833c325445879a28 --shell /bin/sh
+  $ s instance exec --instance-id c-6******-27c4833c325445879a28 --workdir /app
+  $ s instance exec --instance-id c-6******-27c4833c325445879a28 --no-workdir
   $ s instance exec --instance-id \`s invoke  | grep "Invoke instanceId:" |  sed "s/.*: //"\`
 
 Examples with CLI:
-  $ s cli fc3 instance --instance-id c-64fec1fc-27c4833c325445879a28 --region cn-hangzhou --function-name test -a default`,
+  $ s cli fc3 instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --region cn-hangzhou --function-name test -a default
+  $ s cli fc3 instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --region cn-hangzhou --function-name test --shell /bin/sh -a default
+  $ s cli fc3 instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --region cn-hangzhou --function-name test --workdir / -a default
+  $ s cli fc3 instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --region cn-hangzhou --function-name test --no-workdir -a default`,
         summary: 'Execute a command in a instance',
         option: [
           [
@@ -23,6 +29,9 @@ Examples with CLI:
           ['--function-name <functionName>', '[C-Required] Specify function name'],
           ['--instance-id <instanceId>', '[Required] Specify function instance id'],
           ['--cmd <cmd>', '[Optional] Command string to be executed'],
+          ['--shell <shell>', '[Optional] Specify shell to use (e.g., /bin/sh, /bin/bash), default is bash'],
+          ['--workdir <workdir>', '[Optional] Specify initial working directory (e.g., /, /app). If not specified, defaults to /code or / as fallback'],
+          ['--no-workdir', '[Optional] Do not cd to any directory, use container\'s default WORKDIR. Same as --workdir ""'],
           ['--qualifier <qualifier>', '[Optional] Specify version or alias, default is LATEST'],
         ],
       },

src/subCommands/instance/index.ts

@@ -17,8 +17,8 @@ export default class Instance {
   constructor(readonly inputs: IInputs) {
     const opts = parseArgv(inputs.args, {
       alias: { help: 'h', 'assume-yes': 'y' },
-      boolean: ['help', 'y'],
-      string: ['region', 'function-name', 'qualifier'],
+      boolean: ['help', 'y', 'no-workdir'],
+      string: ['region', 'function-name', 'qualifier', 'shell', 'workdir'],
     });
     logger.debug(`Instance opts: ${JSON.stringify(opts)}`);
     const { region, _: subCommands } = opts;
@@ -58,6 +58,8 @@ export default class Instance {
   /**
    * s  instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --cmd "ls -lh"
    * s  instance exec --instance-id c-64fec1fc-27c4833c325445879a28
+   * s  instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --shell /bin/sh
+   * s  instance exec --instance-id c-64fec1fc-27c4833c325445879a28 --workdir /app
    * s  instance exec --instance-id `s invoke  | grep 'Invoke instanceId:' |  sed 's/.*: //'`
    */
   async exec() {
@@ -71,11 +73,26 @@ export default class Instance {
     }
     const qualifier = this.opts.qualifier || 'LATEST';
     const cmd = this.opts.cmd as string;
+    const shell = this.opts.shell || 'bash';
+    const workdir = this.opts.workdir;
+    const noWorkdir = this.opts['no-workdir'];
     let rawData = [];
     if (cmd) {
-      rawData = ['bash', '-c', cmd];
+      rawData = [shell, '-c', cmd];
     } else {
-      rawData = ['bash', '-c', '(cd /code ||  cd / ) && bash'];
+      // Build the default command based on workdir option
+      let defaultCmd: string;
+      if (noWorkdir || workdir === '') {
+        // --no-workdir flag or empty string: don't cd anywhere, use container's default WORKDIR
+        defaultCmd = shell;
+      } else if (workdir) {
+        // User specified a custom workdir
+        defaultCmd = `cd ${workdir} && ${shell}`;
+      } else {
+        // Default behavior (workdir undefined): try /code first, fallback to /
+        defaultCmd = `(cd /code || cd /) && ${shell}`;
+      }
+      rawData = [shell, '-c', defaultCmd];
     }
     await this.fcSdk.instanceExec(functionName, instanceId, rawData, qualifier, true);
   }