Bug 1056865 - Add support for custom env file in Vagrant that is ignored by git (#4857)

.gitignore

@@ -5,6 +5,7 @@ node_modules/
 .vscode/
 yarn-error.log
 npm-error.log
+vagrant/env_local.sh
 
 # vi
 *.swp

docs/installation.md

@@ -127,6 +127,21 @@ To get started:
 - If you just wish to [run the tests](common_tasks.md#running-the-tests),
   you can stop now without performing the remaining steps.
 
+### Customizing Vagrant
+
+If you have some common settings you make in Vagrant (setting an alternate database, or your own
+pulse credentials, etc) then you can create a file that contains `alias`es and `function`s
+to setup those values in a file called `vagrant/env_local.sh`. Git will ignore this file and
+not check it in with your changes.
+
+<!-- prettier-ignore -->
+!!! warning
+    We highly recommend you do NOT ``export`` any values in this file, as it is a foot-gun.
+    If This could lead to a situation where one forgets certain settings were made in that file, and
+    is getting unexpected results in Vagrant.  These changes will persist, event after a
+    ``vagrant destroy``.  For this reason, only use ``alias`` and ``function`` entries, and execute
+    them when you need them.
+
 ### Starting a local Treeherder instance
 
 - Start a Django runserver instance inside the Vagrant VM, to serve the static UI and API requests:

docs/troubleshooting_vagrant.md

@@ -8,6 +8,11 @@
   > vagrant provision
   ```
 
+  Check if you have a file `/vagrant/env_local.sh`. If this file has any errors or is explicitly
+  exporting any environment variables, we recommend updating it so it only has entries of `alias`
+  and `function`.  
+  See [Customizing Vagrant](installation.md#customizing-vagrant)
+
   If that is still unsuccessful, you should attempt a `vagrant destroy` followed by another `vagrant up --provision`.
 
 - If you encounter an error saying _"mount.nfs: requested NFS version or transport protocol is not supported"_, you should restart the kernel server service using this sequence of commands:

vagrant/setup.sh

@@ -40,6 +40,11 @@ ln -sf "$SRC_DIR/vagrant/.profile" "$HOME/.profile"
 sudo ln -sf "$SRC_DIR/vagrant/env.sh" /etc/profile.d/treeherder.sh
 . vagrant/env.sh
 
+if [[ -f vagrant/env_local.sh ]]; then
+    echo '-----> Found custom local_env.sh'
+    sudo ln -sf "$SRC_DIR/vagrant/env_local.sh" /etc/profile.d/treeherder_local.sh
+fi
+
 if ! grep -qs 'node_11.x' /etc/apt/sources.list.d/nodesource.list; then
     echo '-----> Adding APT repository for Node.js'
     sudo curl -sSf https://deb.nodesource.com/gpgkey/nodesource.gpg.key -o /etc/apt/trusted.gpg.d/nodesource.asc