/
shellspout.go
90 lines (81 loc) · 2.12 KB
/
shellspout.go
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// Copyright 2013 Vastech SA (PTY) LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package gostorm
import (
"fmt"
"github.com/jsgilmore/gostorm/core"
"io"
"sync"
)
type ShellSpout interface {
Go()
Exit()
Initialise(spoutConn core.SpoutConn)
}
type shellSpoutImpl struct {
sync.Mutex
spoutConn core.SpoutConn
spout Spout
cleaned bool
}
func NewShellSpout(spout Spout) ShellSpout {
return &shellSpoutImpl{
spout: spout,
}
}
func (this *shellSpoutImpl) Initialise(spoutConn core.SpoutConn) {
this.spoutConn = spoutConn
this.spoutConn.Connect()
this.spout.Open(this.spoutConn.Context(), this.spoutConn)
}
func (this *shellSpoutImpl) Go() {
for {
// This lock prevents the spout exit function being called
// concurrently with another function. The lock is above the
// ReadSpoutMsg to ensure that any messages read from the spout
// in channel will make it to the spout before exit is called.
command, id, err := this.spoutConn.ReadSpoutMsg()
if err == io.EOF {
this.Exit()
return
}
if err != nil {
panic(err)
}
this.Lock()
if this.cleaned && command != "next" {
panic(fmt.Sprintf("ShellSpout: %s message sent to cleaned up spout", command))
}
switch command {
case "next":
this.spout.NextTuple()
case "ack":
this.spout.Acked(id)
case "fail":
this.spout.Failed(id)
default:
panic(fmt.Sprintf("ShellSpout: Unknown command received from Storm: %s", command))
}
this.spoutConn.SendSync()
this.Unlock()
}
}
func (this *shellSpoutImpl) Exit() {
this.Lock()
defer this.Unlock()
if !this.cleaned {
this.spout.Exit()
this.cleaned = true
}
}