On Ferrets and Gophers - Speaker Deck

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On Ferrets and Gophers Introducing FerretDB Alexey Palazhchenko GDG Berlin Golang 2022-01-12

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About me

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About me

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About me

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About me

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About me

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About me

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MongoDB

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MongoDB • Great Developer Experience

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MongoDB • Great Developer Experience • Used to send iPads to community members

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MongoDB • Great Developer Experience • Used to send iPads to community members • Reliability

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MongoDB • Great Developer Experience • Used to send iPads to community members • Reliability • Performance

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MongoDB • Great Developer Experience • Used to send iPads to community members • Reliability • Performance • Scalability

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MongoDB • Great Developer Experience • Used to send iPads to community members • Reliability • Performance • Scalability

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MongoDB • Great Developer Experience • Used to send iPads to community members • Reliability • Performance • Scalability • … does too much?

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MongoDB • Great Developer Experience • Used to send iPads to community members • Reliability • Performance • Scalability • … does too much? • License change

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Not a legal advice

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Not a legal advice

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AGPL v3 SSPL

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AGPL v3 • «If you modify the Program» SSPL

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AGPL v3 • «If you modify the Program» • «All users interacting with it remotely through a computer network» SSPL

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AGPL v3 • «If you modify the Program» • «All users interacting with it remotely through a computer network» • «Interacting» is not a term SSPL

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AGPL v3 • «If you modify the Program» • «All users interacting with it remotely through a computer network» • «Interacting» is not a term • «Corresponding Source» SSPL

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AGPL v3 • «If you modify the Program» • «All users interacting with it remotely through a computer network» • «Interacting» is not a term • «Corresponding Source» • «Including scripts to control those activities» • «If you make the functionality of the Program» • «available to third parties as a service» • «includes, without limitation, […]»  very broad, but not very clear • «Service Source Code» • «including, without limitation, management software, user interfaces, application program interfaces, […], all such that a user could run an instance of the service using the Service Source Code you make available.» SSPL

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SSPL FAQ

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SSPL FAQ

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The SSPL is Not   an Open Source License

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The SSPL is Not   an Open Source License https://opensource.org/node/1099

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Protocol speci fi cation license

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FerretDB

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FerretDB • MongoDB protocol proxy for PostgreSQL

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FerretDB • MongoDB protocol proxy for PostgreSQL • Accepts unmodi fi ed client connections

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FerretDB • MongoDB protocol proxy for PostgreSQL • Accepts unmodi fi ed client connections • Parses BSON queries

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FerretDB • MongoDB protocol proxy for PostgreSQL • Accepts unmodi fi ed client connections • Parses BSON queries • Converts them to SQL

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FerretDB • MongoDB protocol proxy for PostgreSQL • Accepts unmodi fi ed client connections • Parses BSON queries • Converts them to SQL • Sends them to PostgreSQL

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FerretDB • MongoDB protocol proxy for PostgreSQL • Accepts unmodi fi ed client connections • Parses BSON queries • Converts them to SQL • Sends them to PostgreSQL • Apache 2.0 licensed

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PostgreSQL

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PostgreSQL • Reliable

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PostgreSQL • Reliable • Performant

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PostgreSQL • Reliable • Performant • Scalable

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PostgreSQL • Reliable • Performant • Scalable • Feature-rich

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MangoDB Day

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MangoDB Day

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Why Go 1.18?

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Why Go 1.18? Generics

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Why Go 1.18? Generics Fuzzing

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Why Go 1.18? Generics Fuzzing

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Generics

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Generics • Generics do not work there; let's go back to interfaces

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Generics • Generics do not work there; let's go back to interfaces • Let me extract a small example for meetup

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Generics • Generics do not work there; let's go back to interfaces • Let me extract a small example for meetup • Hm, that's not that bad

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BSON Document

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BSON Document • Ordered map

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BSON Document • Ordered map • Keys – string, values – any BSON value, including other documents

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BSON Document • Ordered map • Keys – string, values – any BSON value, including other documents • The central data structure in FerretDB

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Interfaces type BSONType interface { bsontype() // sealed } type Int int func (Int) bsontype() {} type String string func (String) bsontype() {}

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Interfaces type BSONType interface { bsontype() // sealed } type Int int func (Int) bsontype() {} type String string func (String) bsontype() {} type Document struct { m map[string]BSONType keys []string } func (*Document) bsontype() {}

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Interfaces func (d *Document) Set(key string, value BSONType) { if _, ok := d.m[key]; !ok { d.keys = append(d.keys, key) } d.m[key] = value }

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Interfaces d.Set("foo", Int(42))

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Interfaces d.Set("foo", Int(42)) d.Set("qux", nil)

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Generics type BSONType interface { int | string | *Document }

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Generics type BSONType interface { int | string | *Document } type Document struct { m map[string]any keys []string }

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Generics func DocumentSet[T BSONType](d *Document, key string, value T) { if _, ok := d.m[key]; !ok { d.keys = append(d.keys, key) } d.m[key] = value }

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Generics DocumentSet(d, "foo", 42)

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Generics DocumentSet(d, "foo", 42) // DocumentSet(d, "qux", nil)

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Interfaces func MakeDocument(pairs ...BSONType) (*Document, error) { l := len(pairs) if l%2 != 0 { return nil, fmt.Errorf("%d arguments", l)

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Interfaces

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Interfaces MakeDocument(String("invalid number of arguments"))

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Interfaces MakeDocument(String("invalid number of arguments")) MakeDocument(Int(42), String("invalid key type"))

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Interfaces MakeDocument(String("invalid number of arguments")) MakeDocument(Int(42), String("invalid key type")) MakeDocument( String("foo"), Int(42), String("bar"), String("baz"), )

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Generics

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Generics func MakeDocument[T BSONType](key string, value T) *Document

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Generics func MakeDocument[T BSONType](key string, value T) *Document func MakeDocument2[T1, T2 BSONType](key1 string, value1 T1, key2 string, value2 T2) *Document

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Generics func MakeDocument[T BSONType](key string, value T) *Document func MakeDocument2[T1, T2 BSONType](key1 string, value1 T1, key2 string, value2 T2) *Document func MakeDocument3[T1, T2, T3 BSONType](key1 string, value1 T1, key2 string, value2 T2, key3 string, value3 T3) *Document

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Generics vs Interfaces

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Generics vs Interfaces • Better in some aspects

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Generics vs Interfaces • Better in some aspects • Worse in others

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Generics vs Interfaces • Better in some aspects • Worse in others • https://github.com/AlekSi/generics-vs-interfaces

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Use Generics?

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Use Generics?

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Fuzzing

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Fuzzing • testing/quick on steroids

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Fuzzing • testing/quick on steroids • https://go.dev/blog/fuzz-beta

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Fuzzing • testing/quick on steroids • https://go.dev/blog/fuzz-beta • MongoDB binary protocol parsing packages

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Fuzzing • testing/quick on steroids • https://go.dev/blog/fuzz-beta • MongoDB binary protocol parsing packages • They had fuzzing tests even before unit tests

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Fuzzing func FuzzDocument(f *testing.F) { fuzzBSON( f, documentTestCases, func() BSONType { return new(Document) }, ) }

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Fuzzing func fuzzBSON(f *testing.F, tcs []testCase, newF func() BSONType) { for _, tc := range tcs { f.Add(tc.b) } // f.Run(tc.name, func(t *testing.T) f.Fuzz(func(t *testing.T, b []byte) {

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Fuzzing func fuzzBSON(f *testing.F, tcs []testCase, newF func() BSONType) { for _, tc := range tcs { f.Add(tc.b) } // f.Run(tc.name, func(t *testing.T) f.Fuzz(func(t *testing.T, b []byte) { https://github.com/golang/go/issues/47413 👍

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Fuzzing

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Fuzzing • Found many bugs in FerretDB

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Fuzzing • Found many bugs in FerretDB • Found a few bugs in `go test -fuzz`

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Back to FerretDB

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Back to FerretDB • Can't wait for Go 1.18 release to make it easier for contributors

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Back to FerretDB • Can't wait for Go 1.18 release to make it easier for contributors • Speaking of contributors – our community is awesome!

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Back to FerretDB • Can't wait for Go 1.18 release to make it easier for contributors • Speaking of contributors – our community is awesome! • And FerretDB Inc. started hiring about 1 hour ago

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Links • https://www.ferretdb.io • https://github.com/FerretDB ⭐ • https://www.ferretdb.io/careers/ • https://github.com/AlekSi • @paaleksey • https://t.me/HowToGoWrong  (in Russian)