This copies the evaluation logic from the current rules/ package.
The new engine handles the execution process from query string to final result.
It provides query timeout and cancellation and general flexibility for
future changes.
functions.go: Add evaluation implementation. Slight changes to in/out data but
not to the processing logic.
quantile.go: No changes.
analyzer.go: No changes.
engine.go: Actually new part. Mainly consists of evaluation methods
which were not changed.
setup_test.go: Copy of rules/helpers_test.go to setup test storage.
promql_test.go: Copy of rules/rules_test.go.
This commit creates a (so far unused) package. It contains the a custom
lexer/parser for the query language.
ast.go: New AST that interacts well with the parser.
lex.go: Custom lexer (new).
lex_test.go: Lexer tests (new).
parse.go: Custom parser (new).
parse_test.go: Parser tests (new).
functions.go: Changed function type, dummies for parser testing (barely changed/dummies).
printer.go: Adapted from rules/ and adjusted to new AST (mostly unchanged, few additions).
Also, clean up some things in the code (especially introduction of the
chunkLenWithHeader constant to avoid the same expression all over the place).
Benchmark results:
BEFORE
BenchmarkLoadChunksSequentially 5000 283580 ns/op 152143 B/op 312 allocs/op
BenchmarkLoadChunksRandomly 20000 82936 ns/op 39310 B/op 99 allocs/op
BenchmarkLoadChunkDescs 10000 110833 ns/op 15092 B/op 345 allocs/op
AFTER
BenchmarkLoadChunksSequentially 10000 146785 ns/op 152285 B/op 315 allocs/op
BenchmarkLoadChunksRandomly 20000 67598 ns/op 39438 B/op 103 allocs/op
BenchmarkLoadChunkDescs 20000 99631 ns/op 12636 B/op 192 allocs/op
Note that everything is obviously loaded from the page cache (as the
benchmark runs thousands of times with very small series files). In a
real-world scenario, I expect a larger impact, as the disk operations
will more often actually hit the disk. To load ~50 sequential chunks,
this reduces the iops from 100 seeks and 100 reads to 1 seek and 1
read.
The -config.file parameter isn't required or any more special than the
other flags. In order to avoid confusion, this change removes the
special mention again. Instead, the error message if a config file
couldn't be loaded is changed to mention the flag name.
This commit increases the usability by grouping flags based on their
first dot-separated group. Long flag descriptions are broken into lines
printed with indentation.
This commit allows to invoke the rule_checker with a chain of
filepaths as arguments. If no paths are provided it reads from standard
input.
The -rule-file flag remains for backward-compatibility.
On processing errors the return code is now 1. For bad arguments
the return code is now 2.
