deferred-file-operations.md

Deferred file operations

To support self updating services, winsw offers a mechanism to perform file operations before the process you specified in the configuration file gets launched. This is often necessary because Windows prevents a file from being overwritten while it's in use.

To perform file operations, write a text file (in the UTF-8 encoding) at myapp.copies (that is, it's in the same directory as myapp.xml and myapp.exe but with a different file extension), and for each operation add one line:

• To move a file, write a line src>dst. If the dst file already exists it will be overwritten.

The success or failure of these operations will be recorded in the event log.

src and dst should be the full path to file, or you will see failed to copy file.

example:

c:\soft\sshd.exe.new>c:\bin\ssh.exe

The <download> element in the configuration file also provides an useful building block for a self updating service.