Fix #17, ensure the keyfile is writable before creating a user

[jmink]

chef/chef-server#17 is the related issue.

This just ensures the file exists and is writable before creating the user.

Requires manual testing.

[stevendanna]

You likely want to rescue Errno::EACCES as well if we are worried about permissions.

[jmink]

Passed manual testing:

root@default-ubuntu-1204:/# chef-server-ctl user-create foo1 f1 oo foo1@test.com testtest --filename ./foo/file2.key
FATAL: File ./foo/file2.key is not writable.  Check permissions.
root@default-ubuntu-1204:/# chef-server-ctl user-create foo1 f1 oo foo1@test.com testtest --filename ./file2.key
File ./file2.key exists and can be written to.
root@default-ubuntu-1204:/#

[jmink]

Thanks for the comments @stevendanna. I like it a lot better now. The new version has also passed manual testing.

[stevendanna]

I'm confused on how this works for you.

irb(main):002:0> File.writable?("foo", "w")
ArgumentError: wrong number of arguments (2 for 1)
        from (irb):2:in `writable?'

Unfortunately, if the file doesn't exist, I believe that will return false even if the directory is writable:

 File.writable?("./nothinghere")
=> false

I couldn't find a function in the File class that does this, but I think you need something like:

File.exist?(config[:filename]) ? File.writable?(config[:filename]) : File.writable?(File.dirname(config[:filename]))

[jmink]

Thank you again @stevendanna. I was more careful with this test:

root@default-ubuntu-1204:/# chef-server-ctl user-create foo3 f3 oo foo3@test.com testtest --filename ./foo/file4.key
FATAL: File ./foo/file4.key is not writable. Check permissions.
root@default-ubuntu-1204:/# chef-server-ctl user-create foo3 f3 oo foo3@test.com testtest --filename ./file4.key
root@default-ubuntu-1204:/# chef-server-ctl user-create foo4 f4 oo foo4@test.com testtest --filename ./file4.key
root@default-ubuntu-1204:/# chef-server-ctl user-create foo4 f4 oo foo4@test.com testtest --filename ./file4.key
ERROR: Conflict
Response: User 'foo4' already exists
root@default-ubuntu-1204:/#

https://gist.github.com/jmink/e378fd5c408666d07d83

[stevendanna]

👍 Looks good to me.