72 lines
2.3 KiB
Go
72 lines
2.3 KiB
Go
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package proxy
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import (
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"context"
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"time"
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"apps/backend/internal/svc"
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"github.com/zeromicro/go-zero/core/logx"
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)
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// proxyCharge tracks one reserved quota unit for a proxied upstream call.
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//
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// The key mode is resolved once by the caller and reused for both the reservation and the audit
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// event, because resolving separately reads member settings twice and a member editing their
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// keys in between would reserve against one mode and bill the other.
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type proxyCharge struct {
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svcCtx *svc.ServiceContext
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uid int64
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meter string
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mode string
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label string
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source string
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settled bool
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}
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// reserveQuota holds quota for an upcoming call. Pair it with `defer charge.Settle(ctx, &err)`
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// on a named error return so that failures refund instead of charging for nothing.
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func reserveQuota(ctx context.Context, svcCtx *svc.ServiceContext, uid int64, meter, mode, label, source string) (*proxyCharge, error) {
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if err := svcCtx.Usage.PrepareCallWithMode(ctx, uid, meter, mode); err != nil {
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return nil, err
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}
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return &proxyCharge{
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svcCtx: svcCtx, uid: uid, meter: meter, mode: mode, label: label, source: source,
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}, nil
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}
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// Settle commits the charge on success and refunds it on failure.
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func (c *proxyCharge) Settle(ctx context.Context, errp *error) {
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if errp != nil && *errp != nil {
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c.release(ctx)
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return
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}
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c.commit(ctx)
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}
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// commit writes the audit event. The upstream call already succeeded, so a failure here is
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// logged rather than returned: the member has their result and charging them is correct, but
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// losing the event must not be silent either.
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func (c *proxyCharge) commit(ctx context.Context) {
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if c == nil || c.settled {
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return
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}
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c.settled = true
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if _, err := c.svcCtx.Usage.RecordCall(ctx, c.uid, c.meter, c.mode, c.label, c.source); err != nil {
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logx.Errorf("usage record uid=%d meter=%s source=%s: %v", c.uid, c.meter, c.source, err)
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}
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}
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func (c *proxyCharge) release(ctx context.Context) {
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if c == nil || c.settled {
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return
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}
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c.settled = true
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// The request context is often already cancelled on the path being compensated for.
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rctx, cancel := context.WithTimeout(context.WithoutCancel(ctx), 5*time.Second)
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defer cancel()
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if err := c.svcCtx.Usage.ReleaseCall(rctx, c.uid, c.meter, c.mode); err != nil {
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logx.Errorf("usage release uid=%d meter=%s source=%s: %v", c.uid, c.meter, c.source, err)
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}
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}
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