Initial QSfera import

Server/vendor/go-micro.dev/v4/registry/cache/README.md

@@ -0,0 +1,31 @@
+# Registry Cache
+
+Cache is a library that provides a caching layer for the go-micro [registry](https://godoc.org/github.com/micro/go-micro/registry#Registry).
+
+If you're looking for caching in your microservices use the [selector](https://micro.mu/docs/fault-tolerance.html#caching-discovery).
+
+## Interface
+
+```go
+// Cache is the registry cache interface
+type Cache interface {
+	// embed the registry interface
+	registry.Registry
+	// stop the cache watcher
+	Stop()
+}
+```
+
+## Usage
+
+```go
+import (
+	"github.com/micro/go-micro/registry"
+	"github.com/micro/go-micro/registry/cache"
+)
+
+r := registry.NewRegistry()
+cache := cache.New(r)
+
+services, _ := cache.GetService("my.service")
+```

Server/vendor/go-micro.dev/v4/registry/cache/cache.go

@@ -0,0 +1,515 @@
+// Package cache provides a registry cache
+package cache
+
+import (
+	"math"
+	"math/rand"
+	"sync"
+	"time"
+
+	"golang.org/x/sync/singleflight"
+
+	log "go-micro.dev/v4/logger"
+	"go-micro.dev/v4/registry"
+	util "go-micro.dev/v4/util/registry"
+)
+
+// Cache is the registry cache interface.
+type Cache interface {
+	// embed the registry interface
+	registry.Registry
+	// stop the cache watcher
+	Stop()
+}
+
+type Options struct {
+	Logger log.Logger
+	// TTL is the cache TTL
+	TTL time.Duration
+}
+
+type Option func(o *Options)
+
+type cache struct {
+	opts Options
+
+	registry.Registry
+	// status of the registry
+	// used to hold onto the cache
+	// in failure state
+	status error
+	// used to prevent cache breakdwon
+	sg      singleflight.Group
+	cache   map[string][]*registry.Service
+	ttls    map[string]time.Time
+	nttls   map[string]map[string]time.Time // node ttls
+	watched map[string]bool
+
+	// used to stop the cache
+	exit chan bool
+
+	// indicate whether its running
+	watchedRunning map[string]bool
+
+	// registry cache
+	sync.RWMutex
+}
+
+var (
+	DefaultTTL = time.Minute
+)
+
+func backoff(attempts int) time.Duration {
+	if attempts == 0 {
+		return time.Duration(0)
+	}
+	return time.Duration(math.Pow(10, float64(attempts))) * time.Millisecond
+}
+
+func (c *cache) getStatus() error {
+	c.RLock()
+	defer c.RUnlock()
+	return c.status
+}
+
+func (c *cache) setStatus(err error) {
+	c.Lock()
+	c.status = err
+	c.Unlock()
+}
+
+// isValid checks if the service is valid.
+func (c *cache) isValid(services []*registry.Service, ttl time.Time) bool {
+	// no services exist
+	if len(services) == 0 {
+		return false
+	}
+
+	// ttl is invalid
+	if ttl.IsZero() {
+		return false
+	}
+
+	// time since ttl is longer than timeout
+	if time.Since(ttl) > 0 {
+		return false
+	}
+
+	// a node did not get updated
+	for _, s := range services {
+		for _, n := range s.Nodes {
+			nttl := c.nttls[s.Name][n.Id]
+			if time.Since(nttl) > 0 {
+				delete(c.nttls, s.Name)
+				return false
+			}
+		}
+	}
+
+	// ok
+	return true
+}
+
+func (c *cache) quit() bool {
+	select {
+	case <-c.exit:
+		return true
+	default:
+		return false
+	}
+}
+
+func (c *cache) del(service string) {
+	// don't blow away cache in error state
+	if err := c.status; err != nil {
+		return
+	}
+	// otherwise delete entries
+	delete(c.cache, service)
+	delete(c.ttls, service)
+	delete(c.nttls, service)
+}
+
+func (c *cache) get(service string) ([]*registry.Service, error) {
+	// read lock
+	c.RLock()
+
+	// check the cache first
+	services := c.cache[service]
+	// get cache ttl
+	ttl := c.ttls[service]
+	// make a copy
+	cp := util.Copy(services)
+
+	// got services, nodes && within ttl so return cache
+	if c.isValid(cp, ttl) {
+		c.RUnlock()
+		// return services
+		return cp, nil
+	}
+
+	// get does the actual request for a service and cache it
+	get := func(service string, cached []*registry.Service) ([]*registry.Service, error) {
+		// ask the registry
+		val, err, _ := c.sg.Do(service, func() (interface{}, error) {
+			return c.Registry.GetService(service)
+		})
+		services, _ := val.([]*registry.Service)
+		if err != nil {
+			// check the cache
+			if len(cached) > 0 {
+				// set the error status
+				c.setStatus(err)
+
+				// return the stale cache
+				return cached, nil
+			}
+			// otherwise return error
+			return nil, err
+		}
+
+		// reset the status
+		if err := c.getStatus(); err != nil {
+			c.setStatus(nil)
+		}
+
+		// cache results
+		cp := util.Copy(services)
+		c.Lock()
+		for _, s := range services {
+			c.updateNodeTTLs(service, s.Nodes)
+		}
+		c.set(service, services)
+		c.Unlock()
+
+		return cp, nil
+	}
+
+	// watch service if not watched
+	_, ok := c.watched[service]
+
+	// unlock the read lock
+	c.RUnlock()
+
+	// check if its being watched
+	if c.opts.TTL > 0 && !ok {
+		c.Lock()
+
+		// set to watched
+		c.watched[service] = true
+
+		// only kick it off if not running
+		if !c.watchedRunning[service] {
+			go c.run(service)
+		}
+
+		c.Unlock()
+	}
+
+	// get and return services
+	return get(service, cp)
+}
+
+func (c *cache) set(service string, services []*registry.Service) {
+	c.cache[service] = services
+	c.ttls[service] = time.Now().Add(c.opts.TTL)
+}
+
+func (c *cache) updateNodeTTLs(name string, nodes []*registry.Node) {
+	if c.nttls[name] == nil {
+		c.nttls[name] = make(map[string]time.Time)
+	}
+	for _, node := range nodes {
+		c.nttls[name][node.Id] = time.Now().Add(c.opts.TTL)
+	}
+}
+
+func (c *cache) update(res *registry.Result) {
+	if res == nil || res.Service == nil {
+		return
+	}
+
+	c.Lock()
+	defer c.Unlock()
+
+	// only save watched services
+	if _, ok := c.watched[res.Service.Name]; !ok {
+		return
+	}
+
+	services, ok := c.cache[res.Service.Name]
+	if !ok {
+		// we're not going to cache anything
+		// unless there was already a lookup
+		return
+	}
+
+	if len(res.Service.Nodes) == 0 {
+		switch res.Action {
+		case "delete":
+			c.del(res.Service.Name)
+		}
+		return
+	}
+
+	// existing service found
+	var service *registry.Service
+	var index int
+	for i, s := range services {
+		if s.Version == res.Service.Version {
+			service = s
+			index = i
+		}
+	}
+
+	switch res.Action {
+	case "create", "update":
+		c.updateNodeTTLs(res.Service.Name, res.Service.Nodes)
+		if service == nil {
+			c.set(res.Service.Name, append(services, res.Service))
+			return
+		}
+
+		// append old nodes to new service
+		for _, cur := range service.Nodes {
+			var seen bool
+			for _, node := range res.Service.Nodes {
+				if cur.Id == node.Id {
+					seen = true
+					break
+				}
+			}
+			if !seen {
+				res.Service.Nodes = append(res.Service.Nodes, cur)
+			}
+		}
+
+		services[index] = res.Service
+		c.set(res.Service.Name, services)
+	case "delete":
+		if service == nil {
+			return
+		}
+
+		var nodes []*registry.Node
+
+		// filter cur nodes to remove the dead one
+		for _, cur := range service.Nodes {
+			var seen bool
+			for _, del := range res.Service.Nodes {
+				if del.Id == cur.Id {
+					seen = true
+					break
+				}
+			}
+			if !seen {
+				nodes = append(nodes, cur)
+			}
+		}
+
+		// still got nodes, save and return
+		if len(nodes) > 0 {
+			service.Nodes = nodes
+			services[index] = service
+			c.set(service.Name, services)
+			return
+		}
+
+		// zero nodes left
+
+		// only have one thing to delete
+		// nuke the thing
+		if len(services) == 1 {
+			c.del(service.Name)
+			return
+		}
+
+		// still have more than 1 service
+		// check the version and keep what we know
+		var srvs []*registry.Service
+		for _, s := range services {
+			if s.Version != service.Version {
+				srvs = append(srvs, s)
+			}
+		}
+
+		// save
+		c.set(service.Name, srvs)
+	case "override":
+		if service == nil {
+			return
+		}
+
+		c.del(service.Name)
+	}
+}
+
+// run starts the cache watcher loop
+// it creates a new watcher if there's a problem.
+func (c *cache) run(service string) {
+	c.Lock()
+	c.watchedRunning[service] = true
+	c.Unlock()
+	logger := c.opts.Logger
+	// reset watcher on exit
+	defer func() {
+		c.Lock()
+		c.watched = make(map[string]bool)
+		c.watchedRunning[service] = false
+		c.Unlock()
+	}()
+
+	var a, b int
+
+	for {
+		// exit early if already dead
+		if c.quit() {
+			return
+		}
+
+		// jitter before starting
+		j := rand.Int63n(100)
+		time.Sleep(time.Duration(j) * time.Millisecond)
+
+		// create new watcher
+		w, err := c.Registry.Watch(registry.WatchService(service))
+		if err != nil {
+			if c.quit() {
+				return
+			}
+
+			d := backoff(a)
+			c.setStatus(err)
+
+			if a > 3 {
+				logger.Logf(log.DebugLevel, "rcache: ", err, " backing off ", d)
+				a = 0
+			}
+
+			time.Sleep(d)
+			a++
+
+			continue
+		}
+
+		// reset a
+		a = 0
+
+		// watch for events
+		if err := c.watch(w); err != nil {
+			if c.quit() {
+				return
+			}
+
+			d := backoff(b)
+			c.setStatus(err)
+
+			if b > 3 {
+				logger.Logf(log.DebugLevel, "rcache: ", err, " backing off ", d)
+				b = 0
+			}
+
+			time.Sleep(d)
+			b++
+
+			continue
+		}
+
+		// reset b
+		b = 0
+	}
+}
+
+// watch loops the next event and calls update
+// it returns if there's an error.
+func (c *cache) watch(w registry.Watcher) error {
+	// used to stop the watch
+	stop := make(chan bool)
+
+	// manage this loop
+	go func() {
+		defer w.Stop()
+
+		select {
+		// wait for exit
+		case <-c.exit:
+			return
+		// we've been stopped
+		case <-stop:
+			return
+		}
+	}()
+
+	for {
+		res, err := w.Next()
+		if err != nil {
+			close(stop)
+			return err
+		}
+
+		// reset the error status since we succeeded
+		if err := c.getStatus(); err != nil {
+			// reset status
+			c.setStatus(nil)
+		}
+
+		c.update(res)
+	}
+}
+
+func (c *cache) GetService(service string, opts ...registry.GetOption) ([]*registry.Service, error) {
+	// get the service
+	services, err := c.get(service)
+	if err != nil {
+		return nil, err
+	}
+
+	// if there's nothing return err
+	if len(services) == 0 {
+		return nil, registry.ErrNotFound
+	}
+
+	// return services
+	return services, nil
+}
+
+func (c *cache) Stop() {
+	c.Lock()
+	defer c.Unlock()
+
+	select {
+	case <-c.exit:
+		return
+	default:
+		close(c.exit)
+	}
+}
+
+func (c *cache) String() string {
+	return "cache"
+}
+
+// New returns a new cache.
+func New(r registry.Registry, opts ...Option) Cache {
+	rand.Seed(time.Now().UnixNano())
+
+	options := Options{
+		TTL:    DefaultTTL,
+		Logger: log.DefaultLogger,
+	}
+
+	for _, o := range opts {
+		o(&options)
+	}
+
+	return &cache{
+		Registry:       r,
+		opts:           options,
+		watched:        make(map[string]bool),
+		watchedRunning: make(map[string]bool),
+		cache:          make(map[string][]*registry.Service),
+		ttls:           make(map[string]time.Time),
+		nttls:          make(map[string]map[string]time.Time),
+		exit:           make(chan bool),
+	}
+}

Server/vendor/go-micro.dev/v4/registry/cache/options.go

@@ -0,0 +1,21 @@
+package cache
+
+import (
+	"time"
+
+	"go-micro.dev/v4/logger"
+)
+
+// WithTTL sets the cache TTL.
+func WithTTL(t time.Duration) Option {
+	return func(o *Options) {
+		o.TTL = t
+	}
+}
+
+// WithLogger sets the underline logger.
+func WithLogger(l logger.Logger) Option {
+	return func(o *Options) {
+		o.Logger = l
+	}
+}