New `bool` modifier not working in recording rules

[juliusv]

For example, try the expression up > bool 0 with some up and down targets. It works fine in the expression browser, but in a recorded rule it acts like the bool isn't there.

[juliusv]

@brian-brazil @fabxc

[juliusv]

The status page also shows newup{} = up > 0 instead of newup{} = up > bool 0.

[juliusv]

So for the printed text, I guess we just need new printing logic in https://github.com/prometheus/prometheus/blob/master/promql/printer.go. Still doesn't explain the different evaluation behavior between rules and interactive queries though.

[juliusv]

Argh. The printer is indeed the culprit, it seems. Look at this line in recording.go:

https://github.com/prometheus/prometheus/blob/master/rules/recording.go#L47

IMO having to go through serializing and deserializing an expression again internally to evaluate it for a recording rule is quite a wart. Would it be possible to keep it in symbolic form instead and only use the printer-generated serializations for user-targeted output?

[fabxc]

This was a 'good for now' solution. We can certainly keep the AST node directly in rules.

[lock]

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