75 lines
2.1 KiB
Go
75 lines
2.1 KiB
Go
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package api
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import (
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"context"
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"net/http"
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"strings"
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"sync"
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"time"
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"github.com/ponzischeme89/memby/server/internal/appupdate"
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"github.com/ponzischeme89/memby/server/internal/store"
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)
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// updatePolicyCache keeps the policy in memory. It is read on every home request, and a
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// database round trip per home load to answer "nothing to say" would be wasteful.
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type updatePolicyCache struct {
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mu sync.RWMutex
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value appupdate.Policy
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}
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func (c *updatePolicyCache) get() appupdate.Policy {
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c.mu.RLock()
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defer c.mu.RUnlock()
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return c.value
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}
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func (c *updatePolicyCache) set(value appupdate.Policy) {
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c.mu.Lock()
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defer c.mu.Unlock()
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c.value = value
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}
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// LoadUpdatePolicy primes the cached policy. Called at boot and after every change.
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func (s *Server) LoadUpdatePolicy(ctx context.Context) error {
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policy, err := s.store.UpdatePolicy(ctx)
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if err != nil {
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return err
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}
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s.updatePolicy.set(policy)
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return nil
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}
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// WatchUpdatePolicy re-reads the policy periodically, so a change made directly in the
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// database is picked up without a restart.
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func (s *Server) WatchUpdatePolicy(ctx context.Context, interval time.Duration) {
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ticker := time.NewTicker(interval)
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defer ticker.Stop()
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for {
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select {
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case <-ctx.Done():
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return
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case <-ticker.C:
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if err := s.LoadUpdatePolicy(ctx); err != nil {
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s.log.Warn("update policy refresh failed", "error", err)
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}
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}
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}
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}
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// clientVersion reads the version a TV reports. Absent means an older build that predates
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// the header — [appupdate.Decide] treats that as "say nothing".
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func clientVersion(r *http.Request) string {
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return strings.TrimSpace(r.Header.Get("X-Memby-Version"))
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}
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// handleUpdate answers the client's version check.
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//
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// Its own endpoint rather than a field on /v1/home: the home payload is cached per user,
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// while this answer depends on the requesting client's version, so the two cannot share a
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// cache entry. It costs nothing — the policy is held in memory.
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func (s *Server) handleUpdate(w http.ResponseWriter, r *http.Request, _ store.Session) {
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decision := appupdate.Decide(s.updatePolicy.get(), clientVersion(r))
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writeJSON(w, http.StatusOK, decision)
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}
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