only fisrt backup success, second or more failed

[liuxu623]

Consul Template version

v0.21.1

Configuration

backup = true

Debug output

2019/08/31 09:11:40 [WARN] (runner) could not backup "/var/folders/xs/bc89864j0jlb53ty5lz6803m0000gn/T/125157687/724165418": link /var/folders/xs/bc89864j0jlb53ty5lz6803m0000gn/T/125157687/724165418 /var/folders/xs/bc89864j0jlb53ty5lz6803m0000gn/T/125157687/724165418.bak: file exists

Expected behavior

backup success

Actual behavior

backup failed

Steps to reproduce

References

• change backup to use os.Link #1265

[eikenb]

Thanks for the report @liuxu623, I'll get right on this.

[eikenb]

Thought this had test coverage, but it didn't. Sorry about that.

I've written a test and am debating the best fix. The most obvious seems to be to just remove the .bak version before doing the link but I'm taking a few to consider my options.

[eikenb]

I'm thinking the most robust solution will be to os.Rename .bak to .old.bak, then do the os.Link then, if the link is successful, os.Remove .old.bak. Each step is then atomic and won't break anything if one backup fails and won't lose the backup file if it fails (the .old.bak will hang around until a successful backup is made).