M1 MacでAzure Functions Core Tools (Node.js版)が動かない件 (※ワークアラウンド)

# はじめに

<a href="https://qiita.com/kitazaki/items/b531c80b7d0c0411716e">LINE botをVS Codeで開発してAzure Functionsへデプロイするメモ (Node.js版)</a>
を書いたのですが、M1 Macで実行したところローカル環境で動作しませんでした。

Start Debugging[F5]で実行するとgrpc関連でエラーが出力されます。

```zsh
[2021-02-13T01:32:12.816Z] Debugger listening on ws://127.0.0.1:9229/f28a6986-09d1-4104-aae4-aa4ce42a3c82
[2021-02-13T01:32:12.824Z] For help, see: https://nodejs.org/en/docs/inspector
[2021-02-13T01:32:12.824Z] internal/modules/cjs/loader.js:883
[2021-02-13T01:32:12.824Z]   throw err;
[2021-02-13T01:32:12.824Z]   ^
[2021-02-13T01:32:12.825Z] Error: Cannot find module './Worker.js'
[2021-02-13T01:32:12.827Z] Expected directory: node-v83-darwin-arm64-unknown
[2021-02-13T01:32:12.827Z] Found: [node-v57-darwin-ia32-unknown, node-v57-darwin-x64-unknown, node-v57-linux-ia32-glibc, node-v57-linux-x64-glibc, node-v57-win32-ia32-unknown, node-v57-win32-x64-unknown, node-v64-darwin-ia32-unknown, node-v64-darwin-x64-unknown, node-v64-linux-ia32-glibc, node-v64-linux-x64-glibc, node-v64-win32-ia32-unknown, node-v64-win32-x64-unknown, node-v72-darwin-ia32-unknown, node-v72-darwin-x64-unknown, node-v72-linux-ia32-glibc, node-v72-linux-x64-glibc, node-v72-win32-ia32-unknown, node-v72-win32-x64-unknown, node-v83-darwin-ia32-unknown, node-v83-darwin-x64-unknown, node-v83-linux-ia32-glibc, node-v83-linux-x64-glibc, node-v83-win32-ia32-unknown, node-v83-win32-x64-unknown]
[2021-02-13T01:32:12.827Z] Exceeded language worker restart retry count for runtime:node. Shutting down and proactively recycling the Functions Host to recover
[2021-02-13T01:32:12.828Z] This problem can often be fixed by running "npm rebuild" on the current system
[2021-02-13T01:32:12.828Z] Original error: Cannot find module '/opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/grpc/src/node/extension_binary/node-v83-darwin-arm64-unknown/grpc_node.node'
[2021-02-13T01:32:12.829Z] Require stack:
[2021-02-13T01:32:12.829Z] - /opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/worker-bundle.js
[2021-02-13T01:32:12.829Z] - /opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/dist/src/nodejsWorker.js
[2021-02-13T01:32:12.831Z] Require stack:
[2021-02-13T01:32:12.831Z] - /opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/dist/src/nodejsWorker.js
[2021-02-13T01:32:12.831Z]     at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15)
[2021-02-13T01:32:12.831Z]     at Function.Module._load (internal/modules/cjs/loader.js:725:27)
[2021-02-13T01:32:12.831Z]     at Module.require (internal/modules/cjs/loader.js:952:19)
[2021-02-13T01:32:12.831Z]     at require (internal/modules/cjs/helpers.js:88:18)
[2021-02-13T01:32:12.869Z]     at Object.<anonymous> (/opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/dist/src/nodejsWorker.js:45:14)
[2021-02-13T01:32:12.869Z]     at Module._compile (internal/modules/cjs/loader.js:1063:30)
[2021-02-13T01:32:12.869Z]     at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
[2021-02-13T01:32:12.869Z]     at Module.load (internal/modules/cjs/loader.js:928:32)
[2021-02-13T01:32:12.875Z]     at Function.Module._load (internal/modules/cjs/loader.js:769:14)
[2021-02-13T01:32:12.875Z]     at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12) {
[2021-02-13T01:32:12.875Z]   code: 'MODULE_NOT_FOUND',
[2021-02-13T01:32:12.875Z]   requireStack: [
[2021-02-13T01:32:12.875Z]     '/opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/dist/src/nodejsWorker.js'
[2021-02-13T01:32:12.875Z]   ]
[2021-02-13T01:32:12.875Z] }
```

調べてみたところ本家でもissueが上がっていました。
https://github.com/Azure/azure-functions-core-tools/issues/2431

原因は出力内容からnode-v83-darwin-arm64-unknownが存在しないためです。
手動でgrpcモジュールをインストールしてリンクを貼れば動作しました。

```zsh
% npm init -y
% npm install grpc
% ln -s `pwd`/node_modules/grpc/src/node/extension_binary/node-v83-darwin-arm64-unknown /opt/homebrew/Cellar/azure-functions-core-tools@3/3.0.3284/workers/node/grpc/src/node/extension_binary
```

<B>※ Azure Functions Core Toolsをバージョンアップした場合には、再度リンクを貼り直す必要があります。バージョン番号(上記の例では3.0.3284)をインストールしたバージョンに合わせる必要があります。</B>