100 lines
1.6 KiB
Go
100 lines
1.6 KiB
Go
package chain
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import (
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"bytes"
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"sync"
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"github.com/localhots/yeast/unit"
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)
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type (
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Chain struct {
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Flow Flow
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Links []unit.Caller
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}
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)
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const (
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LF = byte(10)
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)
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func (c *Chain) Call(data []byte) (resp []byte, err error) {
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switch c.Flow {
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case SequentialFlow:
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return c.processSequentially(data)
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case ParallelFlow:
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return c.processInParallel(data)
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case DelayedFlow:
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return c.processDelayed(data)
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default:
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panic("Unreachable")
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}
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}
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func (c *Chain) Units() []string {
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// Collecting unique unit names using map
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units := map[string]*struct{}{}
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for _, caller := range c.Links {
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for _, unit := range caller.Units() {
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units[unit] = nil
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}
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}
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// Extracting names to a slice
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uniq := []string{}
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for unit, _ := range units {
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uniq = append(uniq, unit)
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}
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return uniq
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}
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func (c *Chain) processSequentially(data []byte) (resp []byte, err error) {
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for _, caller := range c.Links {
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if resp, err = caller.Call(data); err != nil {
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return
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}
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}
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return
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}
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func (c *Chain) processInParallel(data []byte) (resp []byte, err error) {
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var (
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inbox = make(chan []byte) // This channel must be unbuffered
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buf bytes.Buffer
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wg sync.WaitGroup
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)
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for _, caller := range c.Links {
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wg.Add(1)
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go func() {
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if res, err := caller.Call(data); err == nil {
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inbox <- res
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}
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wg.Done()
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}()
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}
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go func() {
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wg.Wait()
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close(inbox)
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}()
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for {
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if res, ok := <-inbox; ok {
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buf.Write(res)
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buf.WriteByte(LF) // Add linebreak
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} else {
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break
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}
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}
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return buf.Bytes(), nil
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}
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func (c *Chain) processDelayed(data []byte) (resp []byte, err error) {
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for _, caller := range c.Links {
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go caller.Call(data)
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}
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return data, nil
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}
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