forked from apache/beam
/
hash.go
65 lines (56 loc) · 2.06 KB
/
hash.go
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// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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 passert
import (
"crypto/md5"
"encoding/base64"
"fmt"
"sort"
"github.com/apache/beam/sdks/go/pkg/beam"
"github.com/apache/beam/sdks/go/pkg/beam/internal/errors"
)
// Hash validates that the incoming PCollection<string> has the given size and
// base64-encoded MD5 hash code. It buffers the entire PCollection in memory
// and sorts it for determinism.
func Hash(s beam.Scope, col beam.PCollection, name, hash string, size int) {
s = s.Scope(fmt.Sprintf("passert.Hash(%v)", name))
keyed := beam.AddFixedKey(s, col)
grouped := beam.GroupByKey(s, keyed)
beam.ParDo0(s, &hashFn{Name: name, Size: size, Hash: hash}, grouped)
}
type hashFn struct {
Name string `json:"name,omitempty"`
Size int `json:"size,omitempty"`
Hash string `json:"hash,omitempty"`
}
func (f *hashFn) ProcessElement(_ int, lines func(*string) bool) error {
var col []string
var str string
for lines(&str) {
col = append(col, str)
}
sort.Strings(col)
md5W := md5.New()
for _, str := range col {
if _, err := md5W.Write([]byte(str)); err != nil {
panic(err) // cannot fail
}
}
hash := base64.StdEncoding.EncodeToString(md5W.Sum(nil))
if f.Size != len(col) || f.Hash != hash {
return errors.Errorf("passert.Hash(%v) = (%v,%v), want (%v,%v)", f.Name, len(col), hash, f.Size, f.Hash)
}
return nil
}