Add LogQL AST walker #3991
Add LogQL AST walker #3991
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| return e.matchers | ||
| } | ||
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| func (e *matchersExpr) Shardable() bool { return true } | ||
| func (e *MatchersExpr) AppendMatchers(m []*labels.Matcher) { | ||
| e.matchers = append(e.matchers, m...) |
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I'm wondering if we should get the matchers just public. WDYT ?
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Yeah I like this suggestion more as well.
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AFAICS, none of the expression structs exposes any of their field public, e.g. some interesting field would be LiteralExpr.value, *AggrevationExpr.params, OffsetExpr.offset. IMHO ASTs are very sensitive to public scoping of internals. ASTs are often subject of optimizations and thus keeping fields private is a good choice to save your options for later. WDYT?
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I think ultimately we'll make those public if we move to another package.
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Let's move them to public when we and if we publish this to another package.
The follow-up for grafana#3991, it makes using LogQL syntax outside possible, it also makes LogRange implements Expr interface.
What this PR does / why we need it:
The following change set provides a simple extension that enables walking the LoqQL AST for parsed and valid LogQL expressions. This helps to build third-party tooling that can inspect and manipulate LogQL queries before hitting the target Loki query-frontend/querier (e.g. prom-label-proxy).
Furthermore this PR changes:
MatcherExprstruct includes a simpleAppendMatchersmethod to append new label matchers when executing the walking function.walkSampleExpris replaced byexpr.WalkWhich issue(s) this PR fixes:
Special notes for your reviewer:
Checklist
cc @cyriltovena @owen-d