Deployment strategy

[hut8]

Ideally deployments should work like this:

• Somehow get a binary in the right directory on the server (/home/ghc/ghc-app/bin/)
• It should be named ghc-app-<sha1> where the sha1 is the first few hex-encoded bytes
• Binding should always be done with SO_REUSEADDR
• Side idea: bind each build to its own port that is derived from the SHA1 of the binary (Python 3):

app_bytes = open(r'path/to/ghc-app', 'rb').read()
app_hash = hashlib.sha1(app_bytes).digest()
port = int.from_bytes(app_hash, 'big') % (65535 - 1024)

• Start the binary as a child process of the deployment thing listening on a test port on localhost (9001 maybe, since it's over 9000)
• Run some basic tests on that to make sure it returns /stats for example
• Kill the test process
• Switch the link to ghc-app to the new build
• Make a note of the old ghc-app's PID
• Start the new ghc-app just like the old one, again using SO_REUSEADDR. So then two processes listen on the same port.
• Kill old ghc-app