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Monorepo for Tangled
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5.9 kB · 251 lines
Go
at master
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import ( "context" "fmt" "net/http" "slices" "strconv" "strings" "sync" "sync/atomic" "time"
indigoxrpc "github.com/bluesky-social/indigo/xrpc" "tangled.org/core/api/tangled" "tangled.org/core/consts")
const ( versionProbeTimeout = 5 * time.Second versionProbeFresh = 5 * time.Minute versionProbeTrust = time.Hour versionProbeCacheMax = 4096)
type versionProbeEntry struct { version string probedAt time.Time}
type versionProbeCache struct { mu sync.Mutex entries map[string]versionProbeEntry}
func (c *versionProbeCache) get(host string) (versionProbeEntry, bool) { c.mu.Lock() defer c.mu.Unlock() e, ok := c.entries[host] return e, ok}
func (c *versionProbeCache) put(host, version string, at time.Time) { c.mu.Lock() defer c.mu.Unlock() if _, exists := c.entries[host]; !exists && len(c.entries) >= versionProbeCacheMax { c.evictLocked(at) } c.entries[host] = versionProbeEntry{version: version, probedAt: at}}
func (c *versionProbeCache) evictLocked(now time.Time) { oldestHost := "" var oldestAt time.Time for h, e := range c.entries { if now.Sub(e.probedAt) >= versionProbeTrust { delete(c.entries, h) continue } if oldestHost == "" || e.probedAt.Before(oldestAt) { oldestHost, oldestAt = h, e.probedAt } } if len(c.entries) >= versionProbeCacheMax && oldestHost != "" { delete(c.entries, oldestHost) }}
func (c *versionProbeCache) supports(now time.Time, host string, minMajor, minMinor int, failOpen bool, probe func() (string, bool)) bool { if e, ok := c.get(host); ok && now.Sub(e.probedAt) < versionProbeFresh { return atLeast(e.version, minMajor, minMinor) } if version, ok := probe(); ok { c.put(host, version, now) return atLeast(version, minMajor, minMinor) } if e, ok := c.get(host); ok && now.Sub(e.probedAt) < versionProbeTrust { return atLeast(e.version, minMajor, minMinor) } return failOpen}
var probeCache = &versionProbeCache{entries: map[string]versionProbeEntry{}}
type CapStatus int
const ( CapUnknown CapStatus = iota CapAbsent CapPresent)
type negEntry struct { status CapStatus until time.Time}
type NativeLatch interface { IsNative(host string) bool MarkNative(host string)}
type latchBox struct{ l NativeLatch }
type nativeGate struct { memo sync.Map negMemo sync.Map latch atomic.Pointer[latchBox] useOnce sync.Once now func() time.Time}
func (g *nativeGate) clock() time.Time { if g.now != nil { return g.now() } return time.Now()}
func (g *nativeGate) use(l NativeLatch) { g.useOnce.Do(func() { g.latch.Store(&latchBox{l: l}) })}
func (g *nativeGate) currentLatch() NativeLatch { if b := g.latch.Load(); b != nil { return b.l } return nil}
func (g *nativeGate) status(host string, probe func() CapStatus) CapStatus { if _, ok := g.memo.Load(host); ok { return CapPresent } if v, ok := g.negMemo.Load(host); ok { e := v.(negEntry) if g.clock().Before(e.until) { return e.status } g.negMemo.Delete(host) } if l := g.currentLatch(); l != nil && l.IsNative(host) { g.memo.Store(host, struct{}{}) return CapPresent } if s := probe(); s != CapPresent { g.negMemo.Store(host, negEntry{status: s, until: g.clock().Add(versionProbeFresh)}) return s } g.memo.Store(host, struct{}{}) if l := g.currentLatch(); l != nil { l.MarkNative(host) } return CapPresent}
var nativeProbeGate = &nativeGate{}
func UseNativeLatch(l NativeLatch) { nativeProbeGate.use(l)}
func KnotSupports114(ctx context.Context, host string, dev bool) bool { return knotSupportsVersion(ctx, host, dev, 1, 14, true)}
func KnotCapability(ctx context.Context, host string, dev bool, capability consts.Capability) CapStatus { return nativeProbeGate.status(host, func() CapStatus { return knotDeclares(ctx, host, dev, capability) })}
func KnotHasCapability(ctx context.Context, host string, dev bool, capability consts.Capability) bool { return KnotCapability(ctx, host, dev, capability) == CapPresent}
func knotDeclares(ctx context.Context, host string, dev bool, capability consts.Capability) CapStatus { scheme := "https" if dev { scheme = "http" } client := &indigoxrpc.Client{ Host: fmt.Sprintf("%s://%s", scheme, host), Client: &http.Client{Timeout: versionProbeTimeout}, }
ctx, cancel := context.WithTimeout(ctx, versionProbeTimeout) defer cancel()
resp, err := tangled.KnotVersion(ctx, client) if err != nil || resp == nil { return CapUnknown } if slices.Contains(resp.Capabilities, string(capability)) { return CapPresent } return CapAbsent}
func knotSupportsVersion(ctx context.Context, host string, dev bool, minMajor, minMinor int, failOpen bool) bool { return probeCache.supports(time.Now(), host, minMajor, minMinor, failOpen, func() (string, bool) { return probeVersion(ctx, host, dev) })}
func probeVersion(ctx context.Context, host string, dev bool) (string, bool) { scheme := "https" if dev { scheme = "http" } client := &indigoxrpc.Client{ Host: fmt.Sprintf("%s://%s", scheme, host), Client: &http.Client{Timeout: versionProbeTimeout}, }
ctx, cancel := context.WithTimeout(ctx, versionProbeTimeout) defer cancel()
resp, err := tangled.KnotVersion(ctx, client) if err != nil || resp == nil { return "", false } return resp.Version, true}
func atLeast(v string, minMajor, minMinor int) bool { v = strings.TrimSpace(v) v = strings.TrimPrefix(v, "v") if strings.HasPrefix(v, "(devel)") { return true } if v == "" { return false } parts := strings.SplitN(v, ".", 3) if len(parts) < 2 { return false } major, err := strconv.Atoi(parts[0]) if err != nil { return false } minorRaw := strings.SplitN(parts[1], "-", 2)[0] minor, err := strconv.Atoi(minorRaw) if err != nil { return false } return major > minMajor || (major == minMajor && minor >= minMinor)}