`vhd inspect footer --path /path/to/disk.vhd` panics!

[colemickens]

$ go get github.com/Microsoft/azure-vhd-utils-for-go

$ azure-vhd-utils-for-go inspect footer /nix/store/igjb0w7jpjk43sxwk53l21mz118ivghn-azure-image/disk.vhd

panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x18 pc=0x47ebbb]

goroutine 1 [running]:
text/template.(*Template).ExecuteTemplate(0x0, 0x7f4c059961e8, 0xc82003c010, 0x8859d0, 0xa, 0x7fae20, 0xc8200205a0, 0x0, 0x0)
    /nix/store/zfjn6abbd49iyiai3fnvdnxjkqjqwxxi-go-1.5.3/share/go/src/text/template/exec.go:117 +0x3b
main.showVhdFooter(0xc8200c8640)
    /home/cole/code/gopkgs/src/github.com/Microsoft/azure-vhd-utils-for-go/vhdInspectCmdHandler.go:164 +0x6d0
github.com/codegangsta/cli.Command.Run(0x879370, 0x6, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8815b0, 0xf, 0x0, ...)
    /home/cole/code/gopkgs/src/github.com/codegangsta/cli/command.go:174 +0x1397
github.com/codegangsta/cli.(*App).RunAsSubcommand(0xc8200c83c0, 0xc8200c8280, 0x0, 0x0)
    /home/cole/code/gopkgs/src/github.com/codegangsta/cli/app.go:298 +0x11d4
github.com/codegangsta/cli.Command.startApp(0x879898, 0x7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8ccf60, 0x1d, 0x0, ...)
    /home/cole/code/gopkgs/src/github.com/codegangsta/cli/command.go:249 +0x74f
github.com/codegangsta/cli.Command.Run(0x879898, 0x7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8ccf60, 0x1d, 0x0, ...)
    /home/cole/code/gopkgs/src/github.com/codegangsta/cli/command.go:65 +0x79
github.com/codegangsta/cli.(*App).Run(0xc8200c8140, 0xc82000a0a0, 0x5, 0x5, 0x0, 0x0)
    /home/cole/code/gopkgs/src/github.com/codegangsta/cli/app.go:187 +0x1135
main.main()
    /home/cole/code/gopkgs/src/github.com/Microsoft/azure-vhd-utils-for-go/vhd.go:27 +0x2e0

goroutine 17 [syscall, locked to thread]:
runtime.goexit()
    /nix/store/zfjn6abbd49iyiai3fnvdnxjkqjqwxxi-go-1.5.3/share/go/src/runtime/asm_amd64.s:1721 +0x1

[anuchandy]

@colemickens just confirming are you using the latest bits, there was bug in locating template path which i fixed. I just pulled the latest code and tried. It worked

If you have an older version then you might want to remove 'azure-vhd-utils-for-go' from GOPATH/src/Microsoft before "go getting" the latest.

[colemickens]

I just destroyed my entire GOPATH and reran it. Still repros.

$ cd $GOPATH/src/github.com/Mirosoft/azure-vhd-utils-for-go

$ git log
[...]
commit f291a0767221c47a9413038b58a4bbfb3b62ab95
[...]
Date:   Sun Mar 6 21:22:04 2016 -0800
[...]

[anuchandy]

@colemickens could you try this:

1] cd $GOPATH/src/github.com/Mirosoft/azure-vhd-utils-for-go 2] go build 3] ./azure-vhd-utils-for-go inspect footer /nix/store/igjb0w7jpjk43sxwk53l21mz118ivghn-azure-image/disk.vhd

[colemickens]

Yup, that works.

[anuchandy]

cool! The issue is, when we do "go get azure-vhd-utils-for-go", it build the binary "azure-vhd-utils-for-go" and put it in "$GOPATH/bin". This binary is unable to locate the template path because it's relative in the source code.

[colemickens]

Yup, I have a similar problem with one of my projects. I'm currently solving it by distributing the binary + template folder in a docker container and encouraging people to run it that way, but that feels heavy for a tool like this. The other thing I'd considered was just embedding the template files as string constants in my Go source code, but I'm not crazy about that idea either.

[colemickens]

Thanks for the fast support!

[anuchandy]

Thanks for sharing your experience, I guess in case of this tool - reasonable solution is to include template file content as string constants, I will do that.

Let me know if you come across better way of handling this.

[anuchandy]

closing, this issue is addressed by moving the templates to source file.