forked from benthosdev/benthos
/
decode.go
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/
decode.go
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// Copyright (c) 2018 Ashley Jeffs
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package processor
import (
"bytes"
"encoding/base64"
"fmt"
"io/ioutil"
"github.com/Jeffail/benthos/lib/log"
"github.com/Jeffail/benthos/lib/metrics"
"github.com/Jeffail/benthos/lib/response"
"github.com/Jeffail/benthos/lib/types"
)
//------------------------------------------------------------------------------
func init() {
Constructors[TypeDecode] = TypeSpec{
constructor: NewDecode,
description: `
Decodes parts of a message according to the selected scheme. Supported available
schemes are: base64.`,
}
}
//------------------------------------------------------------------------------
// DecodeConfig contains configuration fields for the Decode processor.
type DecodeConfig struct {
Scheme string `json:"scheme" yaml:"scheme"`
Parts []int `json:"parts" yaml:"parts"`
}
// NewDecodeConfig returns a DecodeConfig with default values.
func NewDecodeConfig() DecodeConfig {
return DecodeConfig{
Scheme: "base64",
Parts: []int{},
}
}
//------------------------------------------------------------------------------
type decodeFunc func(bytes []byte) ([]byte, error)
func base64Decode(b []byte) ([]byte, error) {
e := base64.NewDecoder(base64.StdEncoding, bytes.NewReader(b))
return ioutil.ReadAll(e)
}
func strToDecoder(str string) (decodeFunc, error) {
switch str {
case "base64":
return base64Decode, nil
}
return nil, fmt.Errorf("decode scheme not recognised: %v", str)
}
//------------------------------------------------------------------------------
// Decode is a processor that can selectively decode parts of a message
// following a chosen scheme.
type Decode struct {
conf DecodeConfig
fn decodeFunc
log log.Modular
stats metrics.Type
mCount metrics.StatCounter
mSucc metrics.StatCounter
mErr metrics.StatCounter
mSkipped metrics.StatCounter
mSent metrics.StatCounter
mSentParts metrics.StatCounter
}
// NewDecode returns a Decode processor.
func NewDecode(
conf Config, mgr types.Manager, log log.Modular, stats metrics.Type,
) (Type, error) {
cor, err := strToDecoder(conf.Decode.Scheme)
if err != nil {
return nil, err
}
return &Decode{
conf: conf.Decode,
fn: cor,
log: log.NewModule(".processor.decode"),
stats: stats,
mCount: stats.GetCounter("processor.decode.count"),
mSucc: stats.GetCounter("processor.decode.success"),
mErr: stats.GetCounter("processor.decode.error"),
mSkipped: stats.GetCounter("processor.decode.skipped"),
mSent: stats.GetCounter("processor.decode.sent"),
mSentParts: stats.GetCounter("processor.decode.parts.sent"),
}, nil
}
//------------------------------------------------------------------------------
// ProcessMessage applies the processor to a message, either creating >0
// resulting messages or a response to be sent back to the message source.
func (c *Decode) ProcessMessage(msg types.Message) ([]types.Message, types.Response) {
c.mCount.Incr(1)
newMsg := msg.Copy()
targetParts := c.conf.Parts
if len(targetParts) == 0 {
targetParts = make([]int, newMsg.Len())
for i := range targetParts {
targetParts[i] = i
}
}
for _, index := range targetParts {
part := msg.Get(index).Get()
newPart, err := c.fn(part)
if err == nil {
c.mSucc.Incr(1)
newMsg.Get(index).Set(newPart)
} else {
c.log.Errorf("Failed to decode message part: %v\n", err)
c.mErr.Incr(1)
}
}
if newMsg.Len() == 0 {
c.mSkipped.Incr(1)
return nil, response.NewAck()
}
c.mSent.Incr(1)
c.mSentParts.Incr(int64(newMsg.Len()))
msgs := [1]types.Message{newMsg}
return msgs[:], nil
}
//------------------------------------------------------------------------------