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Package docs for lockset with an example. #8

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9 changes: 8 additions & 1 deletion go.work.sum
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Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,8 @@ github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4 h1:gQz4mCb
github.com/rogpeppe/fastuuid v1.2.0 h1:Ppwyp6VYCF1nvBTXL3trRso7mXMlRrw9ooo375wvi2s=
github.com/rogpeppe/go-internal v1.3.0 h1:RR9dF3JtopPvtkroDZuVD7qquD0bnHlKSqaQhgwt8yk=
github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72 h1:qLC7fQah7D6K1B0ujays3HV9gkFtllcxhzImRR7ArPQ=
github.com/spf13/cobra v1.7.0/go.mod h1:uLxZILRyS/50WlhOIKD7W6V5bgeIt+4sICxh6uRMrb0=
github.com/stretchr/objx v0.5.2 h1:xuMeJ0Sdp5ZMRXx/aWO6RZxdr3beISkG5/G/aIRr3pY=
Expand All @@ -79,20 +81,25 @@ golang.org/x/image v0.0.0-20190802002840-cff245a6509b h1:+qEpEAPhDZ1o0x3tHzZTQDA
golang.org/x/mobile v0.0.0-20190719004257-d2bd2a29d028 h1:4+4C/Iv2U4fMZBiMCc98MG1In4gJY5YRhtpDNeDeHWs=
golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
golang.org/x/net v0.14.0/go.mod h1:PpSgVXXLK0OxS0F31C1/tv6XNguvCrnXIDrFMspZIUI=
golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be h1:vEDujvNQGv4jgYKudGeI/+DAX4Jffq6hpD55MmoEvKs=
golang.org/x/oauth2 v0.0.0-20220622183110-fd043fe589d2 h1:+jnHzr9VPj32ykQVai5DNahi9+NSp7yYuCsl5eAQtL0=
golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2 h1:IRJeR9r1pYWsHKTRe/IInb7lYvbBVIqOgsX/u0mbOWY=
golang.org/x/telemetry v0.0.0-20240228155512-f48c80bd79b2/go.mod h1:TeRTkGYfJXctD9OcfyVLyj2J3IxLnKwHJR8f4D8a3YE=
golang.org/x/telemetry v0.0.0-20240521205824-bda55230c457 h1:zf5N6UOrA487eEFacMePxjXAJctxKmyjKUsjA11Uzuk=
golang.org/x/telemetry v0.0.0-20240521205824-bda55230c457/go.mod h1:pRgIJT+bRLFKnoM1ldnzKoxTIn14Yxz928LQRYYgIN0=
golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
golang.org/x/term v0.23.0/go.mod h1:DgV24QBUrK6jhZXl+20l6UWznPlwAHm1Q1mGHtydmSk=
golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
golang.org/x/text v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
golang.org/x/time v0.0.0-20191024005414-555d28b269f0 h1:/5xXl8Y5W96D+TtHSlonuFqGHIWVuyCkGJLwGh9JJFs=
golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
golang.org/x/tools v0.12.0/go.mod h1:Sc0INKfu04TlqNoRA1hgpFZbhYXHPr4V5DzpSBTPqQM=
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43 changes: 43 additions & 0 deletions lockset/executor_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -447,3 +447,46 @@ func TestDedup(t *testing.T) {
// Ensure that the source was not modified.
r.Equal(src, cpy)
}

func TestPhilosophers(t *testing.T) {
ctx := context.Background()

dine := func(ctx context.Context, chopsticks []string) error {
return nil
}

// Construct a new executor that will control access to resources identified by strings
exe := NewExecutor[string](GoRunner(ctx))

// log completion, for testing
log := make([]string, 0)
mu := sync.Mutex{}

monitoring := &Events[string]{
OnComplete: func(task Task[string], sinceScheduled time.Duration) {
mu.Lock()
defer mu.Unlock()
log = append(log, task.Keys()...)
},
}

exe.SetEvents(monitoring)

// Set up our tasks, with the usual dining-philosophers constraints: five actors, five "forks" labeled a-e
alice := TaskFunc([]string{"a", "b"}, dine)
bob := TaskFunc([]string{"b", "c"}, dine)
carol := TaskFunc([]string{"c", "d"}, dine)
dave := TaskFunc([]string{"d", "e"}, dine)
eve := TaskFunc([]string{"e", "a"}, dine)

aliceOut, _ := exe.Schedule(alice)
bobOut, _ := exe.Schedule(bob)
carolOut, _ := exe.Schedule(carol)
daveOut, _ := exe.Schedule(dave)
eveOut, _ := exe.Schedule(eve)

r := require.New(t)

r.NoError(Wait(ctx, []Outcome{aliceOut, bobOut, carolOut, daveOut, eveOut}))
r.Equal([]string{"a", "b", "b", "c", "c", "d", "d", "e", "e", "a"}, log)
}
34 changes: 32 additions & 2 deletions lockset/lockset.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,36 @@
//
// SPDX-License-Identifier: Apache-2.0

// Package lockset contains utilities for ordering access to
// potentially-overlapping resources.
/*
Package lockset contains utilities for ordering access to
potentially-overlapping resources.

A simplified dining philosophers problem might look like this:

// This function is a placeholder for work to be performed while holding zero or more resource locks
dine := func(ctx context.Context, forks []string) error { return nil }

// Construct a new executor that will control access to resources identified by strings
exe := NewExecutor[string](GoRunner(ctx))

// Set up our tasks. We have three tasks, each of which needs two resources labeled a-c
alice := TaskFunc([]string{"a", "b"}, dine)
bob := TaskFunc([]string{"b", "c"}, dine)
carol := TaskFunc([]string{"c", "a"}, dine)

// Schedule our tasks
aliceOut, _ := exe.Schedule(alice)
bobOut, _ := exe.Schedule(bob)
carolOut, _ := exe.Schedule(carol)

// wait until everyone is done
Wait(ctx, []Outcome{aliceOut, bobOut, carolOut})

You construct an Executor, which will coordinate tasks. Each Task needs zero or more "locks": these are not actually
mutexes, or even software objects per se, but are simply identifiers for the resource being protected under the lock.
When you Schedule a Task, you get an Outcome, which can be awaited.

Also included in this package is Queue, which implements the core lock-queueing logic, but is generic across value
types and could be used in other applications with similar dependency-planning needs.
*/
package lockset
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