Generated Configurations might miss some files

[Thomas-Gelf]

Expected Behavior

Generating a Configuration should be an absolutely safe all-or-nothing operation

Current Behavior

In case you manage it to interrupt config rendering, there is a small time window where Config Files are already stored, Config Checksum has been stored, but Config <<==>> File references are still incomplete. They're stored line by line. Nothing bad happens at the first shot, deployment does not happen - as you interrupted it.

However, when you render the configuration again with no configuration change in the meantime, Director will find a reference pointing to an configuration, which matches the config generated in memory. It will therefore just link the existing configuration. Now you get a reference to this broken config - and are allowed to deploy it.

This is VERY hard to reproduce, as there is only a short time frame where this race condition can occur. It usually does not happen in case you "Deploy" a configuration, as it will still deploy the correct config from memory. But it might happen when you first "Generate" a configuration, interrupt the process, "Generate" again, look at the generated Config (manually in the UI) and then "Deploy" that specific generated Config - which unfortunately broke in the DB at the very first shot.

Possible Solution

Storing a generated Configuration should be part of a transaction, and being either COMMITted or ROLLed BACK at once.

[Thomas-Gelf]

NB: the single (and potentially large) files should not be part of this transaction. This is about generated_config entries and linked generated_config_file_config references.

[Thomas-Gelf]

ref/NC/728457