77 lines
1.6 KiB
Go
77 lines
1.6 KiB
Go
package main
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import (
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"context"
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"sync"
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)
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type snapshotKey struct {
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NodeLimit int
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EdgeLimit int
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IncludeBNodes bool
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GraphQueryID string
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}
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type snapshotInflight struct {
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ready chan struct{}
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snapshot GraphResponse
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err error
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}
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type GraphSnapshotService struct {
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sparql *AnzoGraphClient
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cfg Config
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mu sync.Mutex
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cache map[snapshotKey]GraphResponse
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inflight map[snapshotKey]*snapshotInflight
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}
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func NewGraphSnapshotService(sparql *AnzoGraphClient, cfg Config) *GraphSnapshotService {
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return &GraphSnapshotService{
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sparql: sparql,
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cfg: cfg,
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cache: make(map[snapshotKey]GraphResponse),
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inflight: make(map[snapshotKey]*snapshotInflight),
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}
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}
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func (s *GraphSnapshotService) Get(ctx context.Context, nodeLimit int, edgeLimit int, graphQueryID string) (GraphResponse, error) {
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key := snapshotKey{NodeLimit: nodeLimit, EdgeLimit: edgeLimit, IncludeBNodes: s.cfg.IncludeBNodes, GraphQueryID: graphQueryID}
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s.mu.Lock()
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if snap, ok := s.cache[key]; ok {
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s.mu.Unlock()
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return snap, nil
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}
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if inf, ok := s.inflight[key]; ok {
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ready := inf.ready
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s.mu.Unlock()
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select {
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case <-ctx.Done():
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return GraphResponse{}, ctx.Err()
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case <-ready:
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return inf.snapshot, inf.err
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}
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}
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inf := &snapshotInflight{ready: make(chan struct{})}
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s.inflight[key] = inf
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s.mu.Unlock()
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snap, err := fetchGraphSnapshot(ctx, s.sparql, s.cfg, nodeLimit, edgeLimit, graphQueryID)
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s.mu.Lock()
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inf.snapshot = snap
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inf.err = err
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delete(s.inflight, key)
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if err == nil {
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s.cache[key] = snap
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}
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close(inf.ready)
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s.mu.Unlock()
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return snap, err
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}
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