Node Explorer: prompt to add nodes to SSH config file for VSCode remotes list

package.json

@@ -179,6 +179,11 @@
           "when": "(view == node-explorer-view && viewItem == peer-root) || (view == node-explorer-view && viewItem == peer-file-explorer-dir-root)",
           "group": "2_settings@3"
         },
+        {
+          "command": "tailscale.node.addToSSHConfig",
+          "when": "(view == node-explorer-view && viewItem == peer-root) || (view == node-explorer-view && viewItem == peer-file-explorer-dir-root)",
+          "group": "2_settings@3"
+        },
         {
           "command": "tailscale.node.copyIPv4",
           "when": "view == node-explorer-view && viewItem == peer-root",
@@ -331,6 +336,10 @@
         "command": "tailscale.node.setRootDir",
         "title": "Change root directory"
       },
+      {
+        "command": "tailscale.node.addToSSHConfig",
+        "title": "Add to SSH config file"
+      },
       {
         "command": "tailscale.openExternal",
         "title": "Open External Link"
@@ -491,5 +500,8 @@
     "*.{json,md,yml}": [
       "prettier --write"
     ]
+  },
+  "dependencies": {
+    "ssh-config": "^4.4.0"
   }
 }

src/config-manager.ts

@@ -5,6 +5,8 @@ import * as path from 'path';
 interface Host {
   user: string;
   rootDir: string;
+  persistToSSHConfig?: boolean;
+  differentUserFromSSHConfig?: boolean;
 }
 
 interface Config {

src/node-explorer-provider.ts

@@ -11,6 +11,7 @@ import { getUsername } from './utils/host';
 import { FileSystemProvider } from './filesystem-provider';
 import { trimSuffix } from './utils';
 import { EXTENSION_NS } from './constants';
+import { addToSSHConfig, syncSSHConfig } from './utils/sshconfig';
 
 /**
  * Anatomy of the TreeView
@@ -52,6 +53,7 @@ export class NodeExplorerProvider
     this.registerRenameCommand();
     this.registerOpenNodeDetailsCommand();
     this.registerOpenRemoteCodeCommand();
+    this.registerAddToSSHConfigCommand();
     this.registerOpenTerminalCommand();
     this.registerRefresh();
     this.registerOpenDocsLink();
@@ -620,6 +622,10 @@ export class NodeExplorerProvider
       async (node: PeerRoot | FileExplorer) => {
         const { addr, path } = extractAddrAndPath(node);
 
+        if (addr && this.configManager.config.hosts?.[addr].persistToSSHConfig !== false) {
+          await syncSSHConfig(addr, this.configManager);
+        }
+
         if (node instanceof PeerRoot && addr) {
           vscode.commands.executeCommand('vscode.newWindow', {
             remoteAuthority: `ssh-remote+${addr}`,
@@ -640,6 +646,16 @@ export class NodeExplorerProvider
     );
   }
 
+  registerAddToSSHConfigCommand() {
+    vscode.commands.registerCommand('tailscale.node.addToSSHConfig', async (node: PeerRoot) => {
+      addToSSHConfig(
+        this.configManager,
+        node.Address,
+        getUsername(this.configManager, node.Address)
+      );
+    });
+  }
+
   registerOpenNodeDetailsCommand() {
     vscode.commands.registerCommand('tailscale.node.openDetailsLink', async (node: PeerRoot) => {
       vscode.env.openExternal(

src/utils/sshconfig.ts

@@ -0,0 +1,122 @@
+import * as vscode from 'vscode';
+import * as SSHConfig from 'ssh-config';
+import * as os from 'os';
+import { ConfigManager } from '../config-manager';
+import { getUsername } from './host';
+
+function sshConfigFilePath() {
+  const filePath = vscode.workspace.getConfiguration('remote').get<string>('SSH.configFile');
+  return filePath
+    ? vscode.Uri.file(filePath)
+    : vscode.Uri.joinPath(vscode.Uri.file(os.homedir()), './.ssh/config');
+}
+
+async function readSSHConfig() {
+  const configStr = await vscode.workspace.fs
+    .readFile(sshConfigFilePath())
+    .then((a) => Buffer.from(a).toString('utf-8'));
+
+  const config = SSHConfig.parse(configStr);
+
+  const hosts = config
+    // find all the hosts
+    .filter((line): line is SSHConfig.Directive => {
+      return (line as SSHConfig.Directive).param === 'Host';
+    })
+    // get all the host names
+    .flatMap((hostDirective) => hostDirective.value)
+    // get their effective computed option values
+    // (this is necessary because a host might have multiple matching Host blocks,
+    // and the effective options are computed by combining all of them)
+    .map((h) => config.compute(h));
+
+  return { config, hosts };
+}
+
+export async function addToSSHConfig(configManager: ConfigManager, HostName: string, User: string) {
+  const { config, hosts } = await readSSHConfig();
+  const matchingHosts = hosts.filter((h) => h.HostName === HostName);
+  if (matchingHosts.length === 0) {
+    config.append({ Host: HostName, User, HostName });
+  } else {
+    const h = matchingHosts[0];
+    const cfgHost = typeof h.Host === 'string' ? h.Host : h.Host[0];
+    const section = config.find({ Host: cfgHost });
+    if (section && 'config' in section) {
+      let added = false;
+      for (const line of section.config) {
+        if (line.type === SSHConfig.LineType.DIRECTIVE && line.param === 'User') {
+          line.value = User;
+          added = true;
+          break;
+        }
+      }
+      if (!added) {
+        section.config.append({ User });
+      }
+    }
+  }
+  await vscode.workspace.fs.writeFile(
+    sshConfigFilePath(),
+    Buffer.from(SSHConfig.stringify(config))
+  );
+  configManager.setForHost(HostName, 'persistToSSHConfig', true);
+  configManager.setForHost(HostName, 'differentUserFromSSHConfig', false);
+}
+
+export async function syncSSHConfig(addr: string, configManager: ConfigManager) {
+  const { config, hosts } = await readSSHConfig();
+
+  const matchingHosts = hosts.filter((h) => h.HostName === addr);
+  const tsUsername = getUsername(configManager, addr);
+  if (matchingHosts.length === 0) {
+    const add = await vscode.window.showInformationMessage(
+      `Host ${addr} not found in SSH config file, would you like to add it?`,
+      'Yes',
+      'No'
+    );
+    if (add === 'Yes') {
+      await addToSSHConfig(configManager, addr, tsUsername);
+    } else {
+      configManager.setForHost(addr, 'persistToSSHConfig', false);
+    }
+  } else if (!configManager.config.hosts?.[addr].differentUserFromSSHConfig) {
+    for (const h of matchingHosts) {
+      const cfgUsername = typeof h.User === 'string' ? h.User : h.User[0];
+      const cfgHost = typeof h.Host === 'string' ? h.Host : h.Host[0];
+      if (cfgUsername !== tsUsername) {
+        const editHost = await vscode.window.showInformationMessage(
+          `The SSH config file specifies a username (${cfgUsername}) for host ${addr} that
+          is different from the SSH user configured in the Tailscale extension (${tsUsername}). Would you
+          like to update one of them?`,
+          'Update extension',
+          'Update SSH config',
+          'Do nothing'
+        );
+        if (editHost === 'Update extension') {
+          configManager.setForHost(addr, 'user', cfgUsername);
+          configManager.setForHost(addr, 'differentUserFromSSHConfig', false);
+        } else if (editHost === 'Update SSH config') {
+          const section = config.find({ Host: cfgHost });
+          if (section && 'config' in section) {
+            for (const line of section.config) {
+              if (line.type === SSHConfig.LineType.DIRECTIVE && line.param === 'User') {
+                line.value = tsUsername;
+                break;
+              }
+            }
+            await vscode.workspace.fs.writeFile(
+              sshConfigFilePath(),
+              Buffer.from(SSHConfig.stringify(config))
+            );
+            configManager.setForHost(addr, 'differentUserFromSSHConfig', false);
+          }
+        } else {
+          configManager.setForHost(addr, 'differentUserFromSSHConfig', true);
+        }
+      }
+      // according to man ssh_config, ssh uses the first matching entry, so we can break here
+      break;
+    }
+  }
+}

yarn.lock

@@ -5501,6 +5501,11 @@ sql-summary@^1.0.1:
   resolved "https://registry.npmjs.org/sql-summary/-/sql-summary-1.0.1.tgz"
   integrity sha512-IpCr2tpnNkP3Jera4ncexsZUp0enJBLr+pHCyTweMUBrbJsTgQeLWx1FXLhoBj/MvcnUQpkgOn2EY8FKOkUzww==
 
+ssh-config@^4.4.0:
+  version "4.4.0"
+  resolved "https://registry.yarnpkg.com/ssh-config/-/ssh-config-4.4.0.tgz#5fcc595d941661101f0fda8113149e72fc4a4c5d"
+  integrity sha512-W+AAUSsBirHyXqYBUtZ4l0FBAPH/jnklA0KPBfBuBiJVD8LT4LoQST4MCGPziZJYTVvzFmrgrr7j2JWyl/rPIg==
+
 ssh2@^1.14.0:
   version "1.14.0"
   resolved "https://registry.yarnpkg.com/ssh2/-/ssh2-1.14.0.tgz#8f68440e1b768b66942c9e4e4620b2725b3555bb"