Files
mesh-controller/internal/inventory/hold_test.go
T

94 lines
2.6 KiB
Go

//go:build integration
package inventory
import (
"errors"
"strings"
"testing"
"time"
)
// Composing and sending one node's declaration is serialised: a second holder waits for the first.
func TestHoldingANodeMakesTheNextHolderWait(t *testing.T) {
inv := fresh(t)
ctx := t.Context()
release, err := inv.HoldNodes(ctx, []string{"anchor", "laptop"})
if err != nil {
t.Fatal(err)
}
got := make(chan func(), 1)
go func() {
second, err := inv.HoldNodes(ctx, []string{"laptop"})
if err != nil {
t.Error(err)
got <- func() {}
return
}
got <- second
}()
select {
case <-got:
t.Fatal("a node held by one caller was held by another at the same time")
case <-time.After(300 * time.Millisecond):
}
// Another node is not held up.
other, err := inv.HoldNodes(ctx, []string{"joiner"})
if err != nil {
t.Fatal(err)
}
other()
release()
select {
case second := <-got:
second()
case <-time.After(5 * time.Second):
t.Fatal("releasing the node did not let the next holder in")
}
}
// A waiter pins no pool connection while it waits, and gives up after a bounded wait saying which
// node is busy.
func TestAWaiterPinsNoConnectionAndGivesUp(t *testing.T) {
inv := fresh(t)
ctx := t.Context()
release, err := inv.HoldNodes(ctx, []string{"anchor"})
if err != nil {
t.Fatal(err)
}
defer release()
savedWait, savedPoll := HoldWaitFor, HoldPoll
HoldWaitFor, HoldPoll = 1500*time.Millisecond, 50*time.Millisecond
defer func() { HoldWaitFor, HoldPoll = savedWait, savedPoll }()
pool := inv.store.Pool()
base := pool.Stat().AcquiredConns()
const waiters = 3
done := make(chan error, waiters)
for range waiters {
go func() {
_, err := inv.HoldNodes(ctx, []string{"anchor"})
done <- err
}()
}
// While they wait, the pool lends nothing to them for longer than a look: **pinned is held throughout**,
// so at some moment of the wait fewer than all of them hold one. Asked of the least seen over many
// looks, not of the most: a look that lands while every waiter is mid-query is a busy machine, not a
// pinned connection, and on a loaded one (the suite's packages at once, the race detector) it did land.
least := waiters
for range 100 {
time.Sleep(10 * time.Millisecond)
if n := int(pool.Stat().AcquiredConns() - base); n < least {
least = n
}
}
if least >= waiters {
t.Fatalf("%d waiters held %d connections at every look across their wait", waiters, least)
}
for range waiters {
if err := <-done; !errors.Is(err, ErrNodeBusy) || !strings.Contains(err.Error(), "anchor") {
t.Fatalf("a waiter did not give up naming the busy node: %v", err)
}
}
}