65 lines
2.3 KiB
Go
65 lines
2.3 KiB
Go
package kmsvc
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import (
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"context"
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"time"
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kafkamgmtv1 "forgejo.riotpiao.com/rock/kmsvc-proto/gen/kafkamgmt/v1"
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)
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// MaxReceiveMessages mirrors the server-side cap (design.md §2b).
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const MaxReceiveMessages = 10
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// MaxWaitTimeSeconds mirrors the server-side long-poll cap (design.md §2b).
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const MaxWaitTimeSeconds = 20
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// ReceiveOptions configures ReceiveMessage.
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type ReceiveOptions struct {
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// MaxNumberOfMessages caps how many messages are returned (1-10).
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MaxNumberOfMessages int32
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// WaitTimeSeconds requests SQS-style long polling (0-20). The server
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// blocks up to this long before returning an empty result.
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WaitTimeSeconds int32
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// VisibilityTimeoutSeconds overrides the queue's default visibility
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// timeout for the returned messages, if non-zero.
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VisibilityTimeoutSeconds int32
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}
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// ReceiveMessage long-polls queueName for up to opts.WaitTimeSeconds before
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// returning, then returns whatever messages (zero or more) are available.
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//
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// At-least-once delivery: a message may be redelivered (e.g. after the
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// caller's visibility timeout expires without DeleteMessage) — callers must
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// be idempotent or dedup on MessageID/MessageGroupID as appropriate.
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//
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// ctx's deadline is extended internally by a small margin beyond
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// WaitTimeSeconds so a slow network round trip doesn't truncate a poll that
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// the server was about to satisfy; this margin never extends the result
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// beyond what the caller's own ctx allows if ctx is already deadlined sooner.
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func (c *Client) ReceiveMessage(ctx context.Context, queueName string, opts ReceiveOptions) ([]Message, error) {
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callCtx := ctx
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if opts.WaitTimeSeconds > 0 {
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margin := 5 * time.Second
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deadline := time.Now().Add(time.Duration(opts.WaitTimeSeconds)*time.Second + margin)
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var cancel context.CancelFunc
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callCtx, cancel = context.WithDeadline(ctx, deadline)
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defer cancel()
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}
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resp, err := c.stub.ReceiveMessage(callCtx, &kafkamgmtv1.ReceiveMessageRequest{
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QueueName: queueName,
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MaxNumberOfMessages: opts.MaxNumberOfMessages,
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WaitTimeSeconds: opts.WaitTimeSeconds,
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VisibilityTimeoutSeconds: opts.VisibilityTimeoutSeconds,
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})
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if err != nil {
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return nil, mapError(err)
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}
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out := make([]Message, 0, len(resp.Messages))
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for _, m := range resp.Messages {
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out = append(out, toMessage(m))
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}
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return out, nil
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}
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