fix: allow Nixster to be used from within an environment shell

Author: nokome

package-lock.json

@@ -42,6 +42,7 @@
     "@types/mkdirp": "^0.5.2",
     "@types/sprintf-js": "^1.1.1",
     "@types/stream-to-promise": "^2.2.0",
+    "@types/tmp": "0.0.33",
     "@types/yargs": "^12.0.5",
     "all-contributors-cli": "^5.7.0",
     "jest": "^23.6.0",
@@ -64,6 +65,7 @@
     "mkdirp": "^0.5.1",
     "node-pty": "^0.8.0",
     "sprintf-js": "^1.1.2",
+    "tmp": "0.0.33",
     "yargs": "^12.0.5"
   }
 }

package.json

@@ -9,6 +9,7 @@ import mkdirp from 'mkdirp'
 import * as pty from 'node-pty'
 // @ts-ignore
 import spawn from 'await-spawn'
+import tmp from 'tmp'
 import yaml from 'js-yaml'
 
 import * as nix from './nix'
@@ -341,13 +342,31 @@ export default class Environment {
    */
   async enter (command: string = '', pure: boolean = true) {
     const shellName = os.platform() === 'win32' ? 'powershell.exe' : 'bash'
-    const shellArgs = ['--noprofile', '--norc']
+    const shellArgs = ['--noprofile']
 
+    // Path to the shell executable. We need to do this
+    // because the environment may not actually have any shell
+    // in it, in which case, when using `pure` a shell won't be available.
     let shellPath = await spawn('which', [shellName])
     shellPath = shellPath.toString().trim()
+
+    // Inject Nixster into the environment as an alias so we can use it
+    // there without polluting the environment with additional binaries.
+    // During development you'll need to use ---pure=false so that
+    // node is available to run Nixster. In production, when a user
+    // has installed a binary, this shouldn't be necessary
+    let nixsterPath = await spawn('which', ['nixster'])
+    const tempRcFile = tmp.fileSync()
+    fs.writeFileSync(tempRcFile.name, `alias nixster="${nixsterPath.toString().trim()}"\n`)
+    shellArgs.push('--rcfile', tempRcFile.name)
 
+    // Environment variables
     let vars = await this.vars(pure)
     vars = Object.assign(vars, {
+      // Let Nixster know which environment we're in.
+      NIXSTER_ENV: this.name,
+      // Customise the bash prompt so that the user know that they are in
+      // a Nixster environment and which one.
       PS1: '☆ ' + chalk.green.bold(this.name) + ':' + chalk.blue('\\w') + '$ '
     })
 

src/Environment.ts

@@ -91,7 +91,7 @@ yargs
         type: 'array'
       })
       .option('removes', {
-        describe: 'Remove packages from environment',
+        describe: 'Remove packages to environment',
         alias: 'r',
         type: 'array'
       })
@@ -430,7 +430,7 @@ function output (value: any, argv: any = {}, prettifier?: (value: any) => string
  * Add output options to a command.
  *
  * The aim of this approach is to have a consistent
- * and convenient way for users to be able to specify
+ * and convieient way for users to be able to specify
  * the output format across commands.
  *
  * Formats can be specified explicitly e.g.
@@ -483,7 +483,7 @@ function outputOptions (yargs: any) {
  * Create a diagnostic message for the user
  *
  * @param message Message to display
- * @param emoji Emoji to prefix the display
+ * @param emoji Emjoi to prefix the display
  */
 function diag (message: string, emoji: string) {
   if (process.stderr.isTTY && emoji) process.stderr.write(emoji + '  ')