A fast Go avro codec

Overview

Install with:

go get github.com/hamba/avro/v2

Usage

type SimpleRecord struct {
	A int64  `avro:"a"`
	B string `avro:"b"`
}

schema, err := avro.Parse(`{
    "type": "record",
    "name": "simple",
    "namespace": "org.hamba.avro",
    "fields" : [
        {"name": "a", "type": "long"},
        {"name": "b", "type": "string"}
    ]
}`)
if err != nil {
	log.Fatal(err)
}

in := SimpleRecord{A: 27, B: "foo"}

data, err := avro.Marshal(schema, in)
if err != nil {
	log.Fatal(err)
}

fmt.Println(data)
// Outputs: [54 6 102 111 111]

out := SimpleRecord{}
err = avro.Unmarshal(schema, data, &out)
if err != nil {
	log.Fatal(err)
}

fmt.Println(out)
// Outputs: {27 foo}

More examples in the godoc.

Types Conversions

Avro	Go Struct	Go Interface
null	nil	nil
boolean	bool	bool
bytes	[]byte	[]byte
float	float32	float32
double	float64	float64
long	int64	int64
int	int, int32, int16, int8	int
string	string	string
array	[]T	[]interface{}
enum	string	string
fixed	[n]byte	[]byte
map	map[string]T{}	map[string]interface{}
record	struct	map[string]interface{}
union	see below	see below
int.date	time.Time	time.Time
int.time-millis	time.Duration	time.Duration
long.time-micros	time.Duration	time.Duration
long.timestamp-millis	time.Time	time.Time
long.timestamp-micros	time.Time	time.Time
bytes.decimal	*big.Rat	*big.Rat
fixed.decimal	*big.Rat	*big.Rat

Unions

The following union types are accepted: map[string]interface{}, *T and interface{}.

• map[string]interface{}: If the union value is nil, a nil map will be en/decoded. When a non-nil union value is encountered, a single key is en/decoded. The key is the avro type name, or scheam full name in the case of a named schema (enum, fixed or record).
• *T: This is allowed in a "nullable" union. A nullable union is defined as a two schema union, with one of the types being null (ie. ["null", "string"] or ["string", "null"]), in this case a *T is allowed, with T matching the conversion table above.
• interface{}: An interface can be provided and the type or name resolved. Primitive types are pre-registered, but named types, maps and slices will need to be registered with the Register function. In the case of arrays and maps the enclosed schema type or name is postfix to the type with a : separator, e.g "map:string". If any type cannot be resolved the map type above is used unless Config.UnionResolutionError is set to true in which case an error is returned.

TextMarshaler and TextUnmarshaler

The interfaces TextMarshaler and TextUnmarshaler are supported for a string schema type. The object will be tested first for implementation of these interfaces, in the case of a string schema, before trying regular encoding and decoding.

Recursive Structs

At this moment recursive structs are not supported. It is planned for the future.

Benchmark

Benchmark source code can be found at: https://github.com/nrwiersma/avro-benchmarks

BenchmarkGoAvroDecode-10       	  495176	      2413 ns/op	     418 B/op	      27 allocs/op
BenchmarkGoAvroEncode-10       	  420168	      2917 ns/op	     948 B/op	      63 allocs/op
BenchmarkGoGenAvroDecode-10    	  757150	      1552 ns/op	     728 B/op	      45 allocs/op
BenchmarkGoGenAvroEncode-10    	 1882940	       639.0 ns/op	     256 B/op	       3 allocs/op
BenchmarkHambaDecode-10        	 3138063	       383.0 ns/op	      64 B/op	       4 allocs/op
BenchmarkHambaEncode-10        	 4377513	       273.3 ns/op	     112 B/op	       1 allocs/op
BenchmarkLinkedinDecode-10     	 1000000	      1109 ns/op	    1688 B/op	      35 allocs/op
BenchmarkLinkedinEncode-10     	 2641016	       456.0 ns/op	     248 B/op	       5 allocs/op

Always benchmark with your own workload. The result depends heavily on the data input.

EXPERIMENTAL - Go structs generation

Go structs can be generated for you from the schema. The types generated follow the same logic in types conversions

Install the struct generator with:

go install github.com/hamba/avro/v2/cmd/avrogen@<version>

Example usage assuming there's a valid schema in in.avsc:

./app -pkg avro -o bla.go -tags json:snake,yaml:upper-camel in.avsc

Check the options and usage with -h:

avrogen -h

Or use it as a lib in internal commands, it's the gen package