vitess.io/vitess@v0.16.2/go/vt/topo/decode.go (about)

     1  /*
     2  Copyright 2022 The Vitess Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package topo
    18  
    19  import (
    20  	"fmt"
    21  	"path"
    22  
    23  	"google.golang.org/protobuf/encoding/protojson"
    24  	"google.golang.org/protobuf/encoding/prototext"
    25  	"google.golang.org/protobuf/proto"
    26  
    27  	topodatapb "vitess.io/vitess/go/vt/proto/topodata"
    28  	vschemapb "vitess.io/vitess/go/vt/proto/vschema"
    29  )
    30  
    31  // DecodeContent uses the filename to imply a type, and proto-decodes
    32  // the right object, then echoes it as a string.
    33  func DecodeContent(filename string, data []byte, json bool) (string, error) {
    34  	name := path.Base(filename)
    35  	dir := path.Dir(filename)
    36  	var p proto.Message
    37  	switch name {
    38  	case CellInfoFile:
    39  		p = new(topodatapb.CellInfo)
    40  	case KeyspaceFile:
    41  		p = new(topodatapb.Keyspace)
    42  	case ShardFile:
    43  		p = new(topodatapb.Shard)
    44  	case VSchemaFile:
    45  		p = new(vschemapb.Keyspace)
    46  	case ShardReplicationFile:
    47  		p = new(topodatapb.ShardReplication)
    48  	case TabletFile:
    49  		p = new(topodatapb.Tablet)
    50  	case SrvVSchemaFile:
    51  		p = new(vschemapb.SrvVSchema)
    52  	case SrvKeyspaceFile:
    53  		p = new(topodatapb.SrvKeyspace)
    54  	case RoutingRulesFile:
    55  		p = new(vschemapb.RoutingRules)
    56  	default:
    57  		switch dir {
    58  		case "/" + GetExternalVitessClusterDir():
    59  			p = new(topodatapb.ExternalVitessCluster)
    60  		default:
    61  		}
    62  		if p == nil {
    63  			if json {
    64  				return "", fmt.Errorf("unknown topo protobuf type for %v", name)
    65  			}
    66  			return string(data), nil
    67  		}
    68  	}
    69  
    70  	if err := proto.Unmarshal(data, p); err != nil {
    71  		return string(data), err
    72  	}
    73  
    74  	var marshalled []byte
    75  	var err error
    76  	if json {
    77  		marshalled, err = protojson.Marshal(p)
    78  	} else {
    79  		marshalled, err = prototext.Marshal(p)
    80  	}
    81  	return string(marshalled), err
    82  }