Files
mesh-delivery/modules/mesh-delivery-checker/internal/check/bounded.go
T

80 lines
2.2 KiB
Go

package check
import (
"fmt"
"sort"
"sync"
"sync/atomic"
"git.novox.be/novox/mesh-delivery/sdk/buildstep"
)
// ReadWorkers is how many values a read tool asks the bus for at once. Each value is a round trip from the tool through the
// runtime to the bus, so reading a bucket of thousands of keys one after the other outlasts the 30 s a tool call is given
// (issue 1827, as the delivery view's issue 1945). It is a copy of the view's: a few lines are not worth a group delivery
// through mesh-sdk (rules-are-weighed).
const ReadWorkers = 16
// MaxReads bounds the values one call of a read tool reads; past it the answer says it was cut and how to narrow it.
const MaxReads = 1000
// parallel runs read(i) for i in [0, n), at most ReadWorkers at a time, and answers the first error; once one failed no
// further read starts.
func parallel(n int, read func(i int) error) error {
var (
next atomic.Int64
failed atomic.Bool
once sync.Once
first error
wg sync.WaitGroup
)
for w := 0; w < min(ReadWorkers, n); w++ {
wg.Add(1)
go func() {
defer wg.Done()
for !failed.Load() {
i := int(next.Add(1) - 1)
if i >= n {
return
}
if err := read(i); err != nil {
once.Do(func() { first = err })
failed.Store(true)
}
}
}()
}
wg.Wait()
return first
}
// capKeys keeps the first MaxReads keys and answers a note when it cut the rest, "" otherwise.
func capKeys(keys []string, narrow string) ([]string, string) {
if len(keys) <= MaxReads {
return keys, ""
}
return keys[:MaxReads], fmt.Sprintf("read %d of %d matching keys and stopped; %s", MaxReads, len(keys), narrow)
}
// newestFirst sorts step keys (<node>.<id>) by id, newest first: an id is the time in base 36, then six hex digits, so the
// longer id is the later and equal lengths compare as text. A key that is no step key goes last.
func newestFirst(keys []string) {
id := func(k string) (string, bool) {
_, id, err := buildstep.ParseStepKey(k)
return id, err == nil
}
sort.Slice(keys, func(i, j int) bool {
a, aok := id(keys[i])
b, bok := id(keys[j])
switch {
case aok != bok:
return aok
case len(a) != len(b):
return len(a) > len(b)
case a != b:
return a > b
}
return keys[i] > keys[j]
})
}