Allow users to install the packer plugin with `packer init`

[ddelnano]

Allow users to install the packer plugin with `packer init`

[ddelnano]

Actually I closed this too soon. The documentation needs to be updated first.

[4censord]

I have done some tests:
with a known good plugin for comparison upcloud

packer {
  required_plugins {
   xenserver= {
      version = "= v0.3.0-dev9"
      source = "github.com/ddelnano/xenserver"
    }
   upcloud = {
      version = "= v1.0.0"
      source = "github.com/UpCloudLtd/upcloud"
    }
  }
}

PACKER_LOG=1 packer init centos8-init.pkr.hcl
produces [packer-init-log.txt](https://github.com/ddelnano/packer-plugin-xenserver/files/6133370/packer-
init-log.txt)

Looking at the logs, packer ist unable to match the right plugin executable for the provided version.

2021/03/12 23:27:06 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0-dev9_x5.0_linux_amd64.zip, wrong version, expected v0.3.0-dev9 

comparing to the known good, the only real difference is '-dev9'

packer-plugin-upcloud  _v1.0.0     _x5.0_linux_arm64.zip
packer-plugin-xenserver_v0.3.0-dev9_x5.0_linux_amd64.zip

Could you maybe have Github actions build the 'v0.3.0' tag for further testing?

[4censord]

If one manually populates the plugins dir,
packer still errors with
packer validate
Error: no plugin installed for github.com/ddelnano/xenserver = v0.3.0-dev9
packer init
could not find a local nor a remote checksum for plugin "github.com/ddelnano/xenserver" "= v0.3.0-dev9"
it looks as tho it doesnt like the '-dev9' designation

[ddelnano]

It doesn't seem to like the v0.3.0 release I made either.

I updated the "ignoring remote binary" log message and recompiled packer to see why it's not matching the file correctly and see that the file seems to be missing the 'v' prefix

2021/03/12 17:05:11 [DEBUG] github-getter: getting "https://github.com/ddelnano/packer-plugin-xenserver/releases/download/v0.3.0/packer-plugin-xenserver_v0.3.0_SHA256SUMS"
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_freebsd_arm.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_freebsd_arm64.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_linux_arm64.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_linux_arm.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_linux_386.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_darwin_amd64.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_darwin_arm64.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_freebsd_amd64.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_freebsd_386.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_windows_386.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_windows_amd64.zip, wrong version: '0.3.0' does not match expected v0.3.0
2021/03/12 17:05:11 [TRACE] Ignoring remote binary packer-plugin-xenserver_v0.3.0_x5.0_linux_amd64.zip, wrong version: '0.3.0' does not match expected v0.3.0
could not find a local nor a remote checksum for plugin "github.com/ddelnano/xenserver" "= v0.3.0"

[ddelnano]

Turns out this was a packer bug 😄

hashicorp/packer#10760 fixes this issue. Any packer plugin whose name contains a "v" (such as xenserVer) will experience this problem.

[ddelnano]

hashicorp/packer#10760 has been merged and will be released in packer 1.7.1. Once that version is released, I will close this.

[ddelnano]

This now works on packer 1.7.1!

ddelnano@ddelnano-desktop:~/go/src/github.com/xenserver/packer-builder-xenserver$ cat file.pkr.hcl
packer {
  required_plugins {
   xenserver= {
      version = ">= v0.3.0"
      source = "github.com/ddelnano/xenserver"
    }
  }
}

ddelnano@ddelnano-desktop:~/go/src/github.com/xenserver/packer-builder-xenserver$ packer1.7.1 init file.pkr.hcl
Installed plugin github.com/ddelnano/xenserver v0.3.2 in "/home/ddelnano/.packer.d/plugins/github.com/ddelnano/xenserver/packer-plugin-xenserver_v0.3.2_x5.0_linux_amd64"

[ddelnano]

In addition to updating the documentation to use packer init, we need to migrate all the json templates to hcl. That work is being done in #7.

[ddelnano]

Now that #7 is complete and I've updated the documentation (6005f12), this is complete.