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// Copyright [2019] LinkedIn Corp. 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.
package goavro
import (
"bytes"
"encoding/binary"
"encoding/json"
"fmt"
"math"
"strconv"
)
var (
// MaxBlockCount is the maximum number of data items allowed in a single
// block that will be decoded from a binary stream, whether when reading
// blocks to decode an array or a map, or when reading blocks from an OCF
// stream. This check is to ensure decoding binary data will not cause the
// library to over allocate RAM, potentially creating a denial of service on
// the system.
//
// If a particular application needs to decode binary Avro data that
// potentially has more data items in a single block, then this variable may
// be modified at your discretion.
MaxBlockCount = int64(math.MaxInt32)
// MaxBlockSize is the maximum number of bytes that will be allocated for a
// single block of data items when decoding from a binary stream. This check
// is to ensure decoding binary data will not cause the library to over
// allocate RAM, potentially creating a denial of service on the system.
//
// If a particular application needs to decode binary Avro data that
// potentially has more bytes in a single block, then this variable may be
// modified at your discretion.
MaxBlockSize = int64(math.MaxInt32)
)
// Codec supports decoding binary and text Avro data to Go native data types,
// and conversely encoding Go native data types to binary or text Avro data. A
// Codec is created as a stateless structure that can be safely used in multiple
// go routines simultaneously.
type Codec struct {
soeHeader []byte // single-object-encoding header
schemaOriginal string
schemaCanonical string
typeName *name
nativeFromTextual func([]byte) (interface{}, []byte, error)
binaryFromNative func([]byte, interface{}) ([]byte, error)
nativeFromBinary func([]byte) (interface{}, []byte, error)
textualFromNative func([]byte, interface{}) ([]byte, error)
Rabin uint64
}
// codecBuilder holds the 3 kinds of codec builders so they can be
// replaced if needed
// and so they can be passed down the call stack during codec building
type codecBuilder struct {
mapBuilder func(st map[string]*Codec, enclosingNamespace string, schemaMap map[string]interface{}, cb *codecBuilder) (*Codec, error)
stringBuilder func(st map[string]*Codec, enclosingNamespace string, typeName string, schemaMap map[string]interface{}, cb *codecBuilder) (*Codec, error)
sliceBuilder func(st map[string]*Codec, enclosingNamespace string, schemaArray []interface{}, cb *codecBuilder) (*Codec, error)
}
// NewCodec returns a Codec used to translate between a byte slice of either
// binary or textual Avro data and native Go data.
//
// Creating a `Codec` is fast, but ought to be performed exactly once per Avro
// schema to process. Once a `Codec` is created, it may be used multiple times
// to convert data between native form and binary Avro representation, or
// between native form and textual Avro representation.
//
// A particular `Codec` can work with only one Avro schema. However,
// there is no practical limit to how many `Codec`s may be created and
// used in a program. Internally a `Codec` is merely a named tuple of
// four function pointers, and maintains no runtime state that is mutated
// after instantiation. In other words, `Codec`s may be safely used by
// many go routines simultaneously, as your program requires.
//
// codec, err := goavro.NewCodec(`
// {
// "type": "record",
// "name": "LongList",
// "fields" : [
// {"name": "next", "type": ["null", "LongList"], "default": null}
// ]
// }`)
// if err != nil {
// fmt.Println(err)
// }
func NewCodec(schemaSpecification string) (*Codec, error) {
return NewCodecFrom(schemaSpecification, &codecBuilder{
buildCodecForTypeDescribedByMap,
buildCodecForTypeDescribedByString,
buildCodecForTypeDescribedBySlice,
})
}
func NewCodecForStandardJSON(schemaSpecification string) (*Codec, error) {
return NewCodecFrom(schemaSpecification, &codecBuilder{
buildCodecForTypeDescribedByMap,
buildCodecForTypeDescribedByString,
buildCodecForTypeDescribedBySliceJSON,
})
}
func NewCodecFrom(schemaSpecification string, cb *codecBuilder) (*Codec, error) {
var schema interface{}
if err := json.Unmarshal([]byte(schemaSpecification), &schema); err != nil {
return nil, fmt.Errorf("cannot unmarshal schema JSON: %s", err)
}
// bootstrap a symbol table with primitive type codecs for the new codec
st := newSymbolTable()
c, err := buildCodec(st, nullNamespace, schema, cb)
if err != nil {
return nil, err
}
c.schemaCanonical, err = parsingCanonicalForm(schema, "", make(map[string]string))
if err != nil {
return nil, err // should not get here because schema was validated above
}
c.Rabin = rabin([]byte(c.schemaCanonical))
c.soeHeader = []byte{0xC3, 0x01, 0, 0, 0, 0, 0, 0, 0, 0}
binary.LittleEndian.PutUint64(c.soeHeader[2:], c.Rabin)
c.schemaOriginal = schemaSpecification
return c, nil
}
func newSymbolTable() map[string]*Codec {
return map[string]*Codec{
"boolean": {
typeName: &name{"boolean", nullNamespace},
schemaOriginal: "boolean",
schemaCanonical: "boolean",
binaryFromNative: booleanBinaryFromNative,
nativeFromBinary: booleanNativeFromBinary,
nativeFromTextual: booleanNativeFromTextual,
textualFromNative: booleanTextualFromNative,
},
"bytes": {
typeName: &name{"bytes", nullNamespace},
schemaOriginal: "bytes",
schemaCanonical: "bytes",
binaryFromNative: bytesBinaryFromNative,
nativeFromBinary: bytesNativeFromBinary,
nativeFromTextual: bytesNativeFromTextual,
textualFromNative: bytesTextualFromNative,
},
"double": {
typeName: &name{"double", nullNamespace},
schemaOriginal: "double",
schemaCanonical: "double",
binaryFromNative: doubleBinaryFromNative,
nativeFromBinary: doubleNativeFromBinary,
nativeFromTextual: doubleNativeFromTextual,
textualFromNative: doubleTextualFromNative,
},
"float": {
typeName: &name{"float", nullNamespace},
schemaOriginal: "float",
schemaCanonical: "float",
binaryFromNative: floatBinaryFromNative,
nativeFromBinary: floatNativeFromBinary,
nativeFromTextual: floatNativeFromTextual,
textualFromNative: floatTextualFromNative,
},
"int": {
typeName: &name{"int", nullNamespace},
schemaOriginal: "int",
schemaCanonical: "int",
binaryFromNative: intBinaryFromNative,
nativeFromBinary: intNativeFromBinary,
nativeFromTextual: intNativeFromTextual,
textualFromNative: intTextualFromNative,
},
"long": {
typeName: &name{"long", nullNamespace},
schemaOriginal: "long",
schemaCanonical: "long",
binaryFromNative: longBinaryFromNative,
nativeFromBinary: longNativeFromBinary,
nativeFromTextual: longNativeFromTextual,
textualFromNative: longTextualFromNative,
},
"null": {
typeName: &name{"null", nullNamespace},
schemaOriginal: "null",
schemaCanonical: "null",
binaryFromNative: nullBinaryFromNative,
nativeFromBinary: nullNativeFromBinary,
nativeFromTextual: nullNativeFromTextual,
textualFromNative: nullTextualFromNative,
},
"string": {
typeName: &name{"string", nullNamespace},
schemaOriginal: "string",
schemaCanonical: "string",
binaryFromNative: stringBinaryFromNative,
nativeFromBinary: stringNativeFromBinary,
nativeFromTextual: stringNativeFromTextual,
textualFromNative: stringTextualFromNative,
},
// Start of compiled logical types using format typeName.logicalType where there is
// no dependence on schema.
"long.timestamp-millis": {
typeName: &name{"long.timestamp-millis", nullNamespace},
schemaOriginal: "long",
schemaCanonical: "long",
nativeFromTextual: nativeFromTimeStampMillis(longNativeFromTextual),
binaryFromNative: timeStampMillisFromNative(longBinaryFromNative),
nativeFromBinary: nativeFromTimeStampMillis(longNativeFromBinary),
textualFromNative: timeStampMillisFromNative(longTextualFromNative),
},
"long.timestamp-micros": {
typeName: &name{"long.timestamp-micros", nullNamespace},
schemaOriginal: "long",
schemaCanonical: "long",
nativeFromTextual: nativeFromTimeStampMicros(longNativeFromTextual),
binaryFromNative: timeStampMicrosFromNative(longBinaryFromNative),
nativeFromBinary: nativeFromTimeStampMicros(longNativeFromBinary),
textualFromNative: timeStampMicrosFromNative(longTextualFromNative),
},
"int.time-millis": {
typeName: &name{"int.time-millis", nullNamespace},
schemaOriginal: "int",
schemaCanonical: "int",
nativeFromTextual: nativeFromTimeMillis(intNativeFromTextual),
binaryFromNative: timeMillisFromNative(intBinaryFromNative),
nativeFromBinary: nativeFromTimeMillis(intNativeFromBinary),
textualFromNative: timeMillisFromNative(intTextualFromNative),
},
"long.time-micros": {
typeName: &name{"long.time-micros", nullNamespace},
schemaOriginal: "long",
schemaCanonical: "long",
nativeFromTextual: nativeFromTimeMicros(longNativeFromTextual),
binaryFromNative: timeMicrosFromNative(longBinaryFromNative),
nativeFromBinary: nativeFromTimeMicros(longNativeFromBinary),
textualFromNative: timeMicrosFromNative(longTextualFromNative),
},
"int.date": {
typeName: &name{"int.date", nullNamespace},
schemaOriginal: "int",
schemaCanonical: "int",
nativeFromTextual: nativeFromDate(intNativeFromTextual),
binaryFromNative: dateFromNative(intBinaryFromNative),
nativeFromBinary: nativeFromDate(intNativeFromBinary),
textualFromNative: dateFromNative(intTextualFromNative),
},
}
}
// BinaryFromNative appends the binary encoded byte slice representation of the
// provided native datum value to the provided byte slice in accordance with the
// Avro schema supplied when creating the Codec. It is supplied a byte slice to
// which to append the binary encoded data along with the actual data to encode.
// On success, it returns a new byte slice with the encoded bytes appended, and
// a nil error value. On error, it returns the original byte slice, and the
// error message.
//
// func ExampleBinaryFromNative() {
// codec, err := goavro.NewCodec(`
// {
// "type": "record",
// "name": "LongList",
// "fields" : [
// {"name": "next", "type": ["null", "LongList"], "default": null}
// ]
// }`)
// if err != nil {
// fmt.Println(err)
// }
//
// // Convert native Go form to binary Avro data
// binary, err := codec.BinaryFromNative(nil, map[string]interface{}{
// "next": map[string]interface{}{
// "LongList": map[string]interface{}{
// "next": map[string]interface{}{
// "LongList": map[string]interface{}{
// // NOTE: May omit fields when using default value
// },
// },
// },
// },
// })
// if err != nil {
// fmt.Println(err)
// }
//
// fmt.Printf("%#v", binary)
// // Output: []byte{0x2, 0x2, 0x0}
// }
func (c *Codec) BinaryFromNative(buf []byte, datum interface{}) ([]byte, error) {
newBuf, err := c.binaryFromNative(buf, datum)
if err != nil {
return buf, err // if error, return original byte slice
}
return newBuf, nil
}
// NativeFromBinary returns a native datum value from the binary encoded byte
// slice in accordance with the Avro schema supplied when creating the Codec. On
// success, it returns the decoded datum, a byte slice containing the remaining
// undecoded bytes, and a nil error value. On error, it returns nil for
// the datum value, the original byte slice, and the error message.
//
// func ExampleNativeFromBinary() {
// codec, err := goavro.NewCodec(`
// {
// "type": "record",
// "name": "LongList",
// "fields" : [
// {"name": "next", "type": ["null", "LongList"], "default": null}
// ]
// }`)
// if err != nil {
// fmt.Println(err)
// }
//
// // Convert native Go form to binary Avro data
// binary := []byte{0x2, 0x2, 0x0}
//
// native, _, err := codec.NativeFromBinary(binary)
// if err != nil {
// fmt.Println(err)
// }
//
// fmt.Printf("%v", native)
// // Output: map[next:map[LongList:map[next:map[LongList:map[next:<nil>]]]]]
// }
func (c *Codec) NativeFromBinary(buf []byte) (interface{}, []byte, error) {
value, newBuf, err := c.nativeFromBinary(buf)
if err != nil {
return nil, buf, err // if error, return original byte slice
}
return value, newBuf, nil
}
// NativeFromSingle converts Avro data from Single-Object-Encoded format from
// the provided byte slice to Go native data types in accordance with the Avro
// schema supplied when creating the Codec. On success, it returns the decoded
// datum, along with a new byte slice with the decoded bytes consumed, and a nil
// error value. On error, it returns nil for the datum value, the original byte
// slice, and the error message.
//
// func decode(codec *goavro.Codec, buf []byte) error {
// datum, _, err := codec.NativeFromSingle(buf)
// if err != nil {
// return err
// }
// _, err = fmt.Println(datum)
// return err
// }
func (c *Codec) NativeFromSingle(buf []byte) (interface{}, []byte, error) {
fingerprint, newBuf, err := FingerprintFromSOE(buf)
if err != nil {
return nil, buf, err
}
if !bytes.Equal(buf[:len(c.soeHeader)], c.soeHeader) {
return nil, buf, ErrWrongCodec(fingerprint)
}
value, newBuf, err := c.nativeFromBinary(newBuf)
if err != nil {
return nil, buf, err // if error, return original byte slice
}
return value, newBuf, nil
}
// NativeFromTextual converts Avro data in JSON text format from the provided byte
// slice to Go native data types in accordance with the Avro schema supplied
// when creating the Codec. On success, it returns the decoded datum, along with
// a new byte slice with the decoded bytes consumed, and a nil error value. On
// error, it returns nil for the datum value, the original byte slice, and the
// error message.
//
// func ExampleNativeFromTextual() {
// codec, err := goavro.NewCodec(`
// {
// "type": "record",
// "name": "LongList",
// "fields" : [
// {"name": "next", "type": ["null", "LongList"], "default": null}
// ]
// }`)
// if err != nil {
// fmt.Println(err)
// }
//
// // Convert native Go form to text Avro data
// text := []byte(`{"next":{"LongList":{"next":{"LongList":{"next":null}}}}}`)
//
// native, _, err := codec.NativeFromTextual(text)
// if err != nil {
// fmt.Println(err)
// }
//
// fmt.Printf("%v", native)
// // Output: map[next:map[LongList:map[next:map[LongList:map[next:<nil>]]]]]
// }
func (c *Codec) NativeFromTextual(buf []byte) (interface{}, []byte, error) {
value, newBuf, err := c.nativeFromTextual(buf)
if err != nil {
return nil, buf, err // if error, return original byte slice
}
return value, newBuf, nil
}
// SingleFromNative appends the single-object-encoding byte slice representation
// of the provided native datum value to the provided byte slice in accordance
// with the Avro schema supplied when creating the Codec. It is supplied a byte
// slice to which to append the header and binary encoded data, along with the
// actual data to encode. On success, it returns a new byte slice with the
// encoded bytes appended, and a nil error value. On error, it returns the
// original byte slice, and the error message.
//
// func ExampleSingleItemEncoding() {
// codec, err := goavro.NewCodec(`"int"`)
// if err != nil {
// fmt.Fprintf(os.Stderr, "%s\n", err)
// return
// }
//
// buf, err := codec.SingleFromNative(nil, 3)
// if err != nil {
// fmt.Fprintf(os.Stderr, "%s\n", err)
// return
// }
//
// fmt.Println(buf)
// // Output: [195 1 143 92 57 63 26 213 117 114 6]
// }
func (c *Codec) SingleFromNative(buf []byte, datum interface{}) ([]byte, error) {
newBuf, err := c.binaryFromNative(append(buf, c.soeHeader...), datum)
if err != nil {
return buf, err
}
return newBuf, nil
}
// TextualFromNative converts Go native data types to Avro data in JSON text format in
// accordance with the Avro schema supplied when creating the Codec. It is
// supplied a byte slice to which to append the encoded data and the actual data
// to encode. On success, it returns a new byte slice with the encoded bytes
// appended, and a nil error value. On error, it returns the original byte
// slice, and the error message.
//
// func ExampleTextualFromNative() {
// codec, err := goavro.NewCodec(`
// {
// "type": "record",
// "name": "LongList",
// "fields" : [
// {"name": "next", "type": ["null", "LongList"], "default": null}
// ]
// }`)
// if err != nil {
// fmt.Println(err)
// }
//
// // Convert native Go form to text Avro data
// text, err := codec.TextualFromNative(nil, map[string]interface{}{
// "next": map[string]interface{}{
// "LongList": map[string]interface{}{
// "next": map[string]interface{}{
// "LongList": map[string]interface{}{
// // NOTE: May omit fields when using default value
// },
// },
// },
// },
// })
// if err != nil {
// fmt.Println(err)
// }
//
// fmt.Printf("%s", text)
// // Output: {"next":{"LongList":{"next":{"LongList":{"next":null}}}}}
// }
func (c *Codec) TextualFromNative(buf []byte, datum interface{}) ([]byte, error) {
newBuf, err := c.textualFromNative(buf, datum)
if err != nil {
return buf, err // if error, return original byte slice
}
return newBuf, nil
}
// Schema returns the original schema used to create the Codec.
func (c *Codec) Schema() string {
return c.schemaOriginal
}
// CanonicalSchema returns the Parsing Canonical Form of the schema according to
// the Avro specification.
func (c *Codec) CanonicalSchema() string {
return c.schemaCanonical
}
// SchemaCRC64Avro returns a signed 64-bit integer Rabin fingerprint for the
// canonical schema. This method returns the signed 64-bit cast of the unsigned
// 64-bit schema Rabin fingerprint.
//
// DEPRECATED: This method has been replaced by the Rabin structure Codec field
// and is provided for backward compatibility only.
func (c *Codec) SchemaCRC64Avro() int64 {
return int64(c.Rabin)
}
// convert a schema data structure to a codec, prefixing with specified
// namespace
func buildCodec(st map[string]*Codec, enclosingNamespace string, schema interface{}, cb *codecBuilder) (*Codec, error) {
switch schemaType := schema.(type) {
case map[string]interface{}:
return cb.mapBuilder(st, enclosingNamespace, schemaType, cb)
case string:
return cb.stringBuilder(st, enclosingNamespace, schemaType, nil, cb)
case []interface{}:
return cb.sliceBuilder(st, enclosingNamespace, schemaType, cb)
default:
return nil, fmt.Errorf("unknown schema type: %T", schema)
}
}
// Reach into the map, grabbing its "type". Use that to create the codec.
func buildCodecForTypeDescribedByMap(st map[string]*Codec, enclosingNamespace string, schemaMap map[string]interface{}, cb *codecBuilder) (*Codec, error) {
t, ok := schemaMap["type"]
if !ok {
return nil, fmt.Errorf("missing type: %v", schemaMap)
}
switch v := t.(type) {
case string:
// Already defined types may be abbreviated with its string name.
// EXAMPLE: "type":"array"
// EXAMPLE: "type":"enum"
// EXAMPLE: "type":"fixed"
// EXAMPLE: "type":"int"
// EXAMPLE: "type":"record"
// EXAMPLE: "type":"somePreviouslyDefinedCustomTypeString"
return cb.stringBuilder(st, enclosingNamespace, v, schemaMap, cb)
case map[string]interface{}:
return cb.mapBuilder(st, enclosingNamespace, v, cb)
case []interface{}:
return cb.sliceBuilder(st, enclosingNamespace, v, cb)
default:
return nil, fmt.Errorf("type ought to be either string, map[string]interface{}, or []interface{}; received: %T", t)
}
}
func buildCodecForTypeDescribedByString(st map[string]*Codec, enclosingNamespace string, typeName string, schemaMap map[string]interface{}, cb *codecBuilder) (*Codec, error) {
isLogicalType := false
searchType := typeName
// logicalType will be non-nil for those fields without a logicalType property set
if lt := schemaMap["logicalType"]; lt != nil {
isLogicalType = true
searchType = fmt.Sprintf("%s.%s", typeName, lt)
}
// NOTE: When codec already exists, return it. This includes both primitive and
// logicalType codecs added in NewCodec, and user-defined types, added while
// building the codec.
if cd, ok := st[searchType]; ok {
return cd, nil
}
// Avro specification allows abbreviation of type name inside a namespace.
if enclosingNamespace != "" {
if cd, ok := st[enclosingNamespace+"."+typeName]; ok {
return cd, nil
}
}
// There are only a small handful of complex Avro data types.
switch searchType {
case "array":
return makeArrayCodec(st, enclosingNamespace, schemaMap, cb)
case "enum":
return makeEnumCodec(st, enclosingNamespace, schemaMap)
case "fixed":
return makeFixedCodec(st, enclosingNamespace, schemaMap)
case "map":
return makeMapCodec(st, enclosingNamespace, schemaMap, cb)
case "record":
return makeRecordCodec(st, enclosingNamespace, schemaMap, cb)
case "bytes.decimal":
return makeDecimalBytesCodec(st, enclosingNamespace, schemaMap)
case "fixed.decimal":
return makeDecimalFixedCodec(st, enclosingNamespace, schemaMap)
default:
if isLogicalType {
delete(schemaMap, "logicalType")
return buildCodecForTypeDescribedByString(st, enclosingNamespace, typeName, schemaMap, cb)
}
return nil, fmt.Errorf("unknown type name: %q", searchType)
}
}
// notion of enclosing namespace changes when record, enum, or fixed create a
// new namespace, for child objects.
func registerNewCodec(st map[string]*Codec, schemaMap map[string]interface{}, enclosingNamespace string) (*Codec, error) {
n, err := newNameFromSchemaMap(enclosingNamespace, schemaMap)
if err != nil {
return nil, err
}
c := &Codec{typeName: n}
st[n.fullName] = c
return c, nil
}
// ErrWrongCodec is returned when an attempt is made to decode a single-object
// encoded value using the wrong codec.
type ErrWrongCodec uint64
func (e ErrWrongCodec) Error() string { return "wrong codec: " + strconv.FormatUint(uint64(e), 10) }
// ErrNotSingleObjectEncoded is returned when an attempt is made to decode a
// single-object encoded value from a buffer that does not have the correct
// magic prefix.
type ErrNotSingleObjectEncoded string
func (e ErrNotSingleObjectEncoded) Error() string {
return "cannot decode buffer as single-object encoding: " + string(e)
}
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