如何将Packer.io ISO_URL作为命令行参数传递

Question

我想将ISO_URL作为命令行参数进行传递。我试着效仿https://www.packer.io/docs/templates/user-variables.html的一个例子

我的变量部分看起来像

"variables": {
    "build_version": "1.0.0",
    "iso_checksum_type":"md5", 
    "iso_checksum":"453312bf56fc45669fec5ebc0f025ac7",
    "iso_url":"c:\fake.iso"
}

变量引用

   ...
  "iso_checksum": "{{user `iso_checksum`}}",
  "iso_checksum_type":"{{user `iso_checksum_type`}}",
  "iso_url": "{{user `iso_url`}}",
  ...

而build命令是

packer build -var 'iso_url=c:\debian.iso' packerio.json

但是，iso_url未被覆盖，打包程序正在尝试下载fake.iso

为什么？

确切的结果是

virtualbox-iso output will be in this color.

==> virtualbox-iso: Downloading or copying Guest additions
virtualbox-iso: Downloading or copying: file:///C:/Program%20Files/Oracle/VirtualBox/VBoxGuestAdditions.iso
==> virtualbox-iso: Downloading or copying ISO
virtualbox-iso: Downloading or copying: file:///c:/fake.iso
virtualbox-iso: Error downloading: GetFileAttributesEx c:/fake.iso: The system cannot find the file specified.
==> virtualbox-iso: ISO download failed.
Build 'virtualbox-iso' errored: ISO download failed.

==> Some builds didn't complete successfully and had errors:
--> virtualbox-iso: ISO download failed.

==> Builds finished but no artifacts were created.

Answer 1

解决方案是将单引号替换为双引号或省略引号。

packer build -var "iso_url=c:\debian.iso" packerio.json

或

packer build -var iso_url=c:\debian.iso packerio.json

此外，相对路径也适用

packer build -var iso_url=\subfolder_name\debian.iso packerio.json

感谢@RickardvonEssen为我指明了正确的方向。