Convert Packer definition to HCL2

This rewrites the packer JSON files to use the HCL2 language support
added in 1.5 and stabilized in 1.7. The initial conversion was performed
using the `hcl2_upgrade` command but quite a lot of custom work has been
done on top of that.

A base shared definition for the VM is created that defines all the
shared options (CPU, memory, SSH stuff, etc) and then that is
specialized in the `build` block for each `source`, this is where the
differences between Ubuntu and Mint are specified.

Additionally, we now store version information as complex objects that
meet our needs a bit more closely. This is required because some of the
interpolation that we did in JSON is no longer available.

As I was reviewing the VirtualBox builder config I also moved a few
things from manual `VBoxManage` commands to actual packer definitions
but some of those could have been done in the JSON format as well.

Author: laurelmay

.github/workflows/lint.yml

@@ -37,9 +37,6 @@ jobs:
       - name: Install dependencies
         run: |
           pip3 install demjson3
-      - name: Run jsonlint
-        run: |
-          jsonlint packer/*json
       - name: Install Hashicorp repo
         run: >
           wget -O- https://apt.releases.hashicorp.com/gpg | gpg --dearmor |

.gitignore

@@ -7,5 +7,4 @@
 
 # Packer-related binaries
 packer/packer_cache/*
-packer/artifacts_mint/*
-packer/artifacts_ubuntu/*
+packer/artifacts*/*

README.md

@@ -143,10 +143,10 @@ Linux and Windows hosts, but feedback on other platforms is always welcome.
 
 Due to difficulties with Packer packaging, this VM is frequently built with the
 latest version of Packer available directly from Hashicorp. Check the
-`mint-build.json` file for the current minimum version required.
+`main.pkr.hcl` file for the current minimum version required.
 
 Once the prerequisites are installed, change into the `cs-vm-build/packer`
-directory and execute `packer build mint-build.json`. This will take a
+directory and execute `packer build -only "*.mint" .`. This will take a
 considerable amount of time, depending on host resources available, but should
 output progress indicators along the way.
 
@@ -164,15 +164,31 @@ specify `dsound` for Windows, `coreaudio` for Mac.
 ### Building beta images
 
 A large number of variables can be overridden at once by passing a `var-file`
-to Packer. An example of this is provided as `beta-vars.json`, and can be used
+to Packer. An example of this is provided as `mint-beta.pkrvars.hcl`, and can be used
 like this:
 
-`packer build -var-file=beta-vars.json mint-build.json`
+`packer build -var-file=mint-beta.pkrvars.hcl -only "*.mint" .`
 
 Packer allows further overrides, with precedence given to the last option in the
 command. For example, to build a beta image on Windows, use this command:
 
-`packer build -var-file=beta-vars.json -var 'audio=dsound' mint-build.json`
+`packer build -var-file=mint-beta.pkrvars.hcl -var 'audio=dsound' -only "*.mint" .`
+
+### Building Ubuntu images
+
+Native support is available for creating an Ubuntu variant of the image (and in
+fact, all previous commands have specifically excluded Ubuntu image builds). By
+default, the `packer` configuration will build both a Mint and Ubuntu VM. Try it
+with:
+
+`packer build .`
+
+Much as with the previous commands, you can build only an ubuntu-based image by
+running:
+
+`packer build -only "*.ubuntu" .`
+
+Support for building beta variants of Ubuntu images is not currently supported.
 
 ## Contributing
 

packer/beta-vars.json

@@ -0,0 +1,7 @@
+semester = "Fa22"
+
+mint_version = {
+  version = "21"
+  name = "vanessa"
+  beta = true
+}