pax_global_header00006660000000000000000000000064126430373500014515gustar00rootroot0000000000000052 comment=8ddce2a84170772b95dd5d576c48d517b22cac63 gls-4.2.0/000077500000000000000000000000001264303735000123055ustar00rootroot00000000000000gls-4.2.0/LICENSE000066400000000000000000000020471264303735000133150ustar00rootroot00000000000000Copyright (c) 2013, Space Monkey, Inc. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. gls-4.2.0/README.md000066400000000000000000000067551264303735000136010ustar00rootroot00000000000000gls === Goroutine local storage ### IMPORTANT NOTE ### It is my duty to point you to https://blog.golang.org/context, which is how Google solves all of the problems you'd perhaps consider using this package for at scale. One downside to Google's approach is that *all* of your functions must have a new first argument, but after clearing that hurdle everything else is much better. If you aren't interested in this warning, read on. ### Huhwaht? Why? ### Every so often, a thread shows up on the [golang-nuts](https://groups.google.com/d/forum/golang-nuts) asking for some form of goroutine-local-storage, or some kind of goroutine id, or some kind of context. There are a few valid use cases for goroutine-local-storage, one of the most prominent being log line context. One poster was interested in being able to log an HTTP request context id in every log line in the same goroutine as the incoming HTTP request, without having to change every library and function call he was interested in logging. This would be pretty useful. Provided that you could get some kind of goroutine-local-storage, you could call [log.SetOutput](http://golang.org/pkg/log/#SetOutput) with your own logging writer that checks goroutine-local-storage for some context information and adds that context to your log lines. But alas, Andrew Gerrand's typically diplomatic answer to the question of goroutine-local variables was: > We wouldn't even be having this discussion if thread local storage wasn't > useful. But every feature comes at a cost, and in my opinion the cost of > threadlocals far outweighs their benefits. They're just not a good fit for > Go. So, yeah, that makes sense. That's a pretty good reason for why the language won't support a specific and (relatively) unuseful feature that requires some runtime changes, just for the sake of a little bit of log improvement. But does Go require runtime changes? ### How it works ### Go has pretty fantastic introspective and reflective features, but one thing Go doesn't give you is any kind of access to the stack pointer, or frame pointer, or goroutine id, or anything contextual about your current stack. It gives you access to your list of callers, but only along with program counters, which are fixed at compile time. But it does give you the stack. So, we define 16 special functions and embed base-16 tags into the stack using the call order of those 16 functions. Then, we can read our tags back out of the stack looking at the callers list. We then use these tags as an index into a traditional map for implementing this library. ### What are people saying? ### "Wow, that's horrifying." "This is the most terrible thing I have seen in a very long time." "Where is it getting a context from? Is this serializing all the requests? What the heck is the client being bound to? What are these tags? Why does he need callers? Oh god no. No no no." ### Docs ### Please see the docs at http://godoc.org/github.com/jtolds/gls ### Related ### If you're okay relying on the string format of the current runtime stacktrace including a unique goroutine id (not guaranteed by the spec or anything, but very unlikely to change within a Go release), you might be able to squeeze out a bit more performance by using this similar library, inspired by some code Brad Fitzpatrick wrote for debugging his HTTP/2 library: https://github.com/tylerb/gls (in contrast, jtolds/gls doesn't require any knowledge of the string format of the runtime stacktrace, which probably adds unnecessary overhead). gls-4.2.0/context.go000066400000000000000000000100751264303735000143230ustar00rootroot00000000000000// Package gls implements goroutine-local storage. package gls import ( "sync" ) const ( maxCallers = 64 ) var ( stackTagPool = &idPool{} mgrRegistry = make(map[*ContextManager]bool) mgrRegistryMtx sync.RWMutex ) // Values is simply a map of key types to value types. Used by SetValues to // set multiple values at once. type Values map[interface{}]interface{} // ContextManager is the main entrypoint for interacting with // Goroutine-local-storage. You can have multiple independent ContextManagers // at any given time. ContextManagers are usually declared globally for a given // class of context variables. You should use NewContextManager for // construction. type ContextManager struct { mtx sync.RWMutex values map[uint]Values } // NewContextManager returns a brand new ContextManager. It also registers the // new ContextManager in the ContextManager registry which is used by the Go // method. ContextManagers are typically defined globally at package scope. func NewContextManager() *ContextManager { mgr := &ContextManager{values: make(map[uint]Values)} mgrRegistryMtx.Lock() defer mgrRegistryMtx.Unlock() mgrRegistry[mgr] = true return mgr } // Unregister removes a ContextManager from the global registry, used by the // Go method. Only intended for use when you're completely done with a // ContextManager. Use of Unregister at all is rare. func (m *ContextManager) Unregister() { mgrRegistryMtx.Lock() defer mgrRegistryMtx.Unlock() delete(mgrRegistry, m) } // SetValues takes a collection of values and a function to call for those // values to be set in. Anything further down the stack will have the set // values available through GetValue. SetValues will add new values or replace // existing values of the same key and will not mutate or change values for // previous stack frames. // SetValues is slow (makes a copy of all current and new values for the new // gls-context) in order to reduce the amount of lookups GetValue requires. func (m *ContextManager) SetValues(new_values Values, context_call func()) { if len(new_values) == 0 { context_call() return } tags := readStackTags(1) m.mtx.Lock() values := new_values for _, tag := range tags { if existing_values, ok := m.values[tag]; ok { // oh, we found existing values, let's make a copy values = make(Values, len(existing_values)+len(new_values)) for key, val := range existing_values { values[key] = val } for key, val := range new_values { values[key] = val } break } } new_tag := stackTagPool.Acquire() m.values[new_tag] = values m.mtx.Unlock() defer func() { m.mtx.Lock() delete(m.values, new_tag) m.mtx.Unlock() stackTagPool.Release(new_tag) }() addStackTag(new_tag, context_call) } // GetValue will return a previously set value, provided that the value was set // by SetValues somewhere higher up the stack. If the value is not found, ok // will be false. func (m *ContextManager) GetValue(key interface{}) (value interface{}, ok bool) { tags := readStackTags(1) m.mtx.RLock() defer m.mtx.RUnlock() for _, tag := range tags { if values, ok := m.values[tag]; ok { value, ok := values[key] return value, ok } } return "", false } func (m *ContextManager) getValues() Values { tags := readStackTags(2) m.mtx.RLock() defer m.mtx.RUnlock() for _, tag := range tags { if values, ok := m.values[tag]; ok { return values } } return nil } // Go preserves ContextManager values and Goroutine-local-storage across new // goroutine invocations. The Go method makes a copy of all existing values on // all registered context managers and makes sure they are still set after // kicking off the provided function in a new goroutine. If you don't use this // Go method instead of the standard 'go' keyword, you will lose values in // ContextManagers, as goroutines have brand new stacks. func Go(cb func()) { mgrRegistryMtx.RLock() defer mgrRegistryMtx.RUnlock() for mgr, _ := range mgrRegistry { values := mgr.getValues() if len(values) > 0 { mgr_copy := mgr cb_copy := cb cb = func() { mgr_copy.SetValues(values, cb_copy) } } } go cb() } gls-4.2.0/context_test.go000066400000000000000000000053471264303735000153700ustar00rootroot00000000000000package gls import ( "fmt" "sync" "testing" ) func TestContexts(t *testing.T) { mgr1 := NewContextManager() mgr2 := NewContextManager() CheckVal := func(mgr *ContextManager, key, exp_val string) { val, ok := mgr.GetValue(key) if len(exp_val) == 0 { if ok { t.Fatalf("expected no value for key %s, got %s", key, val) } return } if !ok { t.Fatalf("expected value %s for key %s, got no value", exp_val, key) } if exp_val != val { t.Fatalf("expected value %s for key %s, got %s", exp_val, key, val) } } Check := func(exp_m1v1, exp_m1v2, exp_m2v1, exp_m2v2 string) { CheckVal(mgr1, "key1", exp_m1v1) CheckVal(mgr1, "key2", exp_m1v2) CheckVal(mgr2, "key1", exp_m2v1) CheckVal(mgr2, "key2", exp_m2v2) } Check("", "", "", "") mgr2.SetValues(Values{"key1": "val1c"}, func() { Check("", "", "val1c", "") mgr1.SetValues(Values{"key1": "val1a"}, func() { Check("val1a", "", "val1c", "") mgr1.SetValues(Values{"key2": "val1b"}, func() { Check("val1a", "val1b", "val1c", "") var wg sync.WaitGroup wg.Add(2) go func() { defer wg.Done() Check("", "", "", "") }() Go(func() { defer wg.Done() Check("val1a", "val1b", "val1c", "") }) wg.Wait() }) }) }) } func ExampleContextManager_SetValues() { var ( mgr = NewContextManager() request_id_key = GenSym() ) MyLog := func() { if request_id, ok := mgr.GetValue(request_id_key); ok { fmt.Println("My request id is:", request_id) } else { fmt.Println("No request id found") } } mgr.SetValues(Values{request_id_key: "12345"}, func() { MyLog() }) MyLog() // Output: My request id is: 12345 // No request id found } func ExampleGo() { var ( mgr = NewContextManager() request_id_key = GenSym() ) MyLog := func() { if request_id, ok := mgr.GetValue(request_id_key); ok { fmt.Println("My request id is:", request_id) } else { fmt.Println("No request id found") } } mgr.SetValues(Values{request_id_key: "12345"}, func() { var wg sync.WaitGroup wg.Add(1) go func() { defer wg.Done() MyLog() }() wg.Wait() wg.Add(1) Go(func() { defer wg.Done() MyLog() }) wg.Wait() }) // Output: No request id found // My request id is: 12345 } func BenchmarkGetValue(b *testing.B) { mgr := NewContextManager() mgr.SetValues(Values{"test_key": "test_val"}, func() { b.ResetTimer() for i := 0; i < b.N; i++ { val, ok := mgr.GetValue("test_key") if !ok || val != "test_val" { b.FailNow() } } }) } func BenchmarkSetValues(b *testing.B) { mgr := NewContextManager() for i := 0; i < b.N/2; i++ { mgr.SetValues(Values{"test_key": "test_val"}, func() { mgr.SetValues(Values{"test_key2": "test_val2"}, func() {}) }) } } gls-4.2.0/gen_sym.go000066400000000000000000000004411264303735000142740ustar00rootroot00000000000000package gls var ( symPool = &idPool{} ) // ContextKey is a throwaway value you can use as a key to a ContextManager type ContextKey struct{ id uint } // GenSym will return a brand new, never-before-used ContextKey func GenSym() ContextKey { return ContextKey{id: symPool.Acquire()} } gls-4.2.0/id_pool.go000066400000000000000000000011711264303735000142610ustar00rootroot00000000000000package gls // though this could probably be better at keeping ids smaller, the goal of // this class is to keep a registry of the smallest unique integer ids // per-process possible import ( "sync" ) type idPool struct { mtx sync.Mutex released []uint max_id uint } func (p *idPool) Acquire() (id uint) { p.mtx.Lock() defer p.mtx.Unlock() if len(p.released) > 0 { id = p.released[len(p.released)-1] p.released = p.released[:len(p.released)-1] return id } id = p.max_id p.max_id++ return id } func (p *idPool) Release(id uint) { p.mtx.Lock() defer p.mtx.Unlock() p.released = append(p.released, id) } gls-4.2.0/stack_tags.go000066400000000000000000000024031264303735000147560ustar00rootroot00000000000000package gls // so, basically, we're going to encode integer tags in base-16 on the stack const ( bitWidth = 4 ) func addStackTag(tag uint, context_call func()) { if context_call == nil { return } markS(tag, context_call) } func markS(tag uint, cb func()) { _m(tag, cb) } func mark0(tag uint, cb func()) { _m(tag, cb) } func mark1(tag uint, cb func()) { _m(tag, cb) } func mark2(tag uint, cb func()) { _m(tag, cb) } func mark3(tag uint, cb func()) { _m(tag, cb) } func mark4(tag uint, cb func()) { _m(tag, cb) } func mark5(tag uint, cb func()) { _m(tag, cb) } func mark6(tag uint, cb func()) { _m(tag, cb) } func mark7(tag uint, cb func()) { _m(tag, cb) } func mark8(tag uint, cb func()) { _m(tag, cb) } func mark9(tag uint, cb func()) { _m(tag, cb) } func markA(tag uint, cb func()) { _m(tag, cb) } func markB(tag uint, cb func()) { _m(tag, cb) } func markC(tag uint, cb func()) { _m(tag, cb) } func markD(tag uint, cb func()) { _m(tag, cb) } func markE(tag uint, cb func()) { _m(tag, cb) } func markF(tag uint, cb func()) { _m(tag, cb) } var pc_lookup = make(map[uintptr]int8, 17) var mark_lookup [16]func(uint, func()) func _m(tag_remainder uint, cb func()) { if tag_remainder == 0 { cb() } else { mark_lookup[tag_remainder&0xf](tag_remainder>>bitWidth, cb) } } gls-4.2.0/stack_tags_js.go000066400000000000000000000042671264303735000154640ustar00rootroot00000000000000// +build js package gls // This file is used for GopherJS builds, which don't have normal runtime support import ( "regexp" "strconv" "strings" "github.com/gopherjs/gopherjs/js" ) var stackRE = regexp.MustCompile("\\s+at (\\S*) \\([^:]+:(\\d+):(\\d+)") func findPtr() uintptr { jsStack := js.Global.Get("Error").New().Get("stack").Call("split", "\n") for i := 1; i < jsStack.Get("length").Int(); i++ { item := jsStack.Index(i).String() matches := stackRE.FindAllStringSubmatch(item, -1) if matches == nil { return 0 } pkgPath := matches[0][1] if strings.HasPrefix(pkgPath, "$packages.github.com/jtolds/gls.mark") { line, _ := strconv.Atoi(matches[0][2]) char, _ := strconv.Atoi(matches[0][3]) x := (uintptr(line) << 16) | uintptr(char) return x } } return 0 } func init() { setEntries := func(f func(uint, func()), v int8) { var ptr uintptr f(0, func() { ptr = findPtr() }) pc_lookup[ptr] = v if v >= 0 { mark_lookup[v] = f } } setEntries(markS, -0x1) setEntries(mark0, 0x0) setEntries(mark1, 0x1) setEntries(mark2, 0x2) setEntries(mark3, 0x3) setEntries(mark4, 0x4) setEntries(mark5, 0x5) setEntries(mark6, 0x6) setEntries(mark7, 0x7) setEntries(mark8, 0x8) setEntries(mark9, 0x9) setEntries(markA, 0xa) setEntries(markB, 0xb) setEntries(markC, 0xc) setEntries(markD, 0xd) setEntries(markE, 0xe) setEntries(markF, 0xf) } func currentStack(skip int) (stack []uintptr) { jsStack := js.Global.Get("Error").New().Get("stack").Call("split", "\n") for i := skip + 2; i < jsStack.Get("length").Int(); i++ { item := jsStack.Index(i).String() matches := stackRE.FindAllStringSubmatch(item, -1) if matches == nil { return stack } line, _ := strconv.Atoi(matches[0][2]) char, _ := strconv.Atoi(matches[0][3]) x := (uintptr(line) << 16) | uintptr(char)&0xffff stack = append(stack, x) } return stack } func readStackTags(skip int) (tags []uint) { stack := currentStack(skip) var current_tag uint for _, pc := range stack { val, ok := pc_lookup[pc] if !ok { continue } if val < 0 { tags = append(tags, current_tag) current_tag = 0 continue } current_tag <<= bitWidth current_tag += uint(val) } return } gls-4.2.0/stack_tags_main.go000066400000000000000000000022731264303735000157670ustar00rootroot00000000000000// +build !js package gls // This file is used for standard Go builds, which have the expected runtime support import ( "reflect" "runtime" ) func init() { setEntries := func(f func(uint, func()), v int8) { pc_lookup[reflect.ValueOf(f).Pointer()] = v if v >= 0 { mark_lookup[v] = f } } setEntries(markS, -0x1) setEntries(mark0, 0x0) setEntries(mark1, 0x1) setEntries(mark2, 0x2) setEntries(mark3, 0x3) setEntries(mark4, 0x4) setEntries(mark5, 0x5) setEntries(mark6, 0x6) setEntries(mark7, 0x7) setEntries(mark8, 0x8) setEntries(mark9, 0x9) setEntries(markA, 0xa) setEntries(markB, 0xb) setEntries(markC, 0xc) setEntries(markD, 0xd) setEntries(markE, 0xe) setEntries(markF, 0xf) } func currentStack(skip int) []uintptr { stack := make([]uintptr, maxCallers) return stack[:runtime.Callers(3+skip, stack)] } func readStackTags(skip int) (tags []uint) { stack := currentStack(skip) var current_tag uint for _, pc := range stack { pc = runtime.FuncForPC(pc).Entry() val, ok := pc_lookup[pc] if !ok { continue } if val < 0 { tags = append(tags, current_tag) current_tag = 0 continue } current_tag <<= bitWidth current_tag += uint(val) } return }