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* first draft for event system - includes example Signed-off-by: jkoberg <jkoberg@owncloud.com> * add event middleware Signed-off-by: jkoberg <jkoberg@owncloud.com> * events: distinguish grantee userid and groupid Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de> * seperate consumer from publisher Signed-off-by: jkoberg <jkoberg@owncloud.com> * code review suggestions Signed-off-by: jkoberg <jkoberg@owncloud.com> * simplify example Signed-off-by: jkoberg <jkoberg@owncloud.com> * add changelog Signed-off-by: jkoberg <jkoberg@owncloud.com> * make nats server configurable Signed-off-by: jkoberg <jkoberg@owncloud.com> * add license headers Signed-off-by: jkoberg <jkoberg@owncloud.com> * cheat the linter Signed-off-by: jkoberg <jkoberg@owncloud.com> Co-authored-by: Jörn Friedrich Dreyer <jfd@butonic.de>
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| Enhancement: introduce events | ||
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| This will introduce events into the system. Events are a simple way to bring information from | ||
| one service to another. Read `pkg/events/example` and subfolders for more information | ||
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| https://github.com/cs3org/reva/pull/2522 | ||
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| // Copyright 2018-2021 CERN | ||
| // | ||
| // 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. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
| // | ||
| // In applying this license, CERN does not waive the privileges and immunities | ||
| // granted to it by virtue of its status as an Intergovernmental Organization | ||
| // or submit itself to any jurisdiction. | ||
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| package eventsmiddleware | ||
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| import ( | ||
| collaboration "github.com/cs3org/go-cs3apis/cs3/sharing/collaboration/v1beta1" | ||
| "github.com/cs3org/reva/pkg/events" | ||
| ) | ||
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| // ShareCreated converts response to event | ||
| func ShareCreated(r *collaboration.CreateShareResponse) events.ShareCreated { | ||
| e := events.ShareCreated{ | ||
| Sharer: r.Share.Creator, | ||
| GranteeUserID: r.Share.GetGrantee().GetUserId(), | ||
| GranteeGroupID: r.Share.GetGrantee().GetGroupId(), | ||
| ItemID: r.Share.ResourceId, | ||
| CTime: r.Share.Ctime, | ||
| } | ||
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| return e | ||
| } |
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| // Copyright 2018-2021 CERN | ||
| // | ||
| // 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. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
| // | ||
| // In applying this license, CERN does not waive the privileges and immunities | ||
| // granted to it by virtue of its status as an Intergovernmental Organization | ||
| // or submit itself to any jurisdiction. | ||
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| package eventsmiddleware | ||
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| import ( | ||
| "context" | ||
| "fmt" | ||
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| "go-micro.dev/v4/util/log" | ||
| "google.golang.org/grpc" | ||
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| "github.com/asim/go-micro/plugins/events/nats/v4" | ||
| collaboration "github.com/cs3org/go-cs3apis/cs3/sharing/collaboration/v1beta1" | ||
| "github.com/cs3org/reva/pkg/events" | ||
| "github.com/cs3org/reva/pkg/events/server" | ||
| "github.com/cs3org/reva/pkg/rgrpc" | ||
| ) | ||
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| const ( | ||
| defaultPriority = 200 | ||
| ) | ||
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| func init() { | ||
| rgrpc.RegisterUnaryInterceptor("eventsmiddleware", NewUnary) | ||
| } | ||
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| // NewUnary returns a new unary interceptor that emits events when needed | ||
| // no lint because of the switch statement that should be extendable | ||
| //nolint:gocritic | ||
| func NewUnary(m map[string]interface{}) (grpc.UnaryServerInterceptor, int, error) { | ||
| publisher, err := publisherFromConfig(m) | ||
| if err != nil { | ||
| return nil, 0, err | ||
| } | ||
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| interceptor := func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) { | ||
| res, err := handler(ctx, req) | ||
| if err != nil { | ||
| return res, err | ||
| } | ||
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| var ev interface{} | ||
| switch v := res.(type) { | ||
| case *collaboration.CreateShareResponse: | ||
| ev = ShareCreated(v) | ||
| } | ||
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| if ev != nil { | ||
| if err := events.Publish(publisher, ev); err != nil { | ||
| log.Error(err) | ||
| } | ||
| } | ||
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| return res, nil | ||
| } | ||
| return interceptor, defaultPriority, nil | ||
| } | ||
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| // NewStream returns a new server stream interceptor | ||
| // that creates the application context. | ||
| func NewStream() grpc.StreamServerInterceptor { | ||
| interceptor := func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error { | ||
| // TODO: Use ss.RecvMsg() and ss.SendMsg() to send events from a stream | ||
| return handler(srv, ss) | ||
| } | ||
| return interceptor | ||
| } | ||
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| func publisherFromConfig(m map[string]interface{}) (events.Publisher, error) { | ||
| typ := m["type"].(string) | ||
| switch typ { | ||
| default: | ||
| return nil, fmt.Errorf("stream type '%s' not supported", typ) | ||
| case "nats": | ||
| address := m["address"].(string) | ||
| cid := m["clusterID"].(string) | ||
| return server.NewNatsStream(nats.Address(address), nats.ClusterID(cid)) | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,107 @@ | ||
| // Copyright 2018-2021 CERN | ||
| // | ||
| // 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. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
| // | ||
| // In applying this license, CERN does not waive the privileges and immunities | ||
| // granted to it by virtue of its status as an Intergovernmental Organization | ||
| // or submit itself to any jurisdiction. | ||
|
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| package events | ||
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| import ( | ||
| "log" | ||
| "reflect" | ||
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| "go-micro.dev/v4/events" | ||
| ) | ||
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| var ( | ||
| // MainQueueName is the name of the main queue | ||
| // All events will go through here as they are forwarded to the consumer via the | ||
| // group name | ||
| // TODO: "fan-out" so not all events go through the same queue? requires investigation | ||
| MainQueueName = "main-queue" | ||
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| // MetadatakeyEventType is the key used for the eventtype in the metadata map of the event | ||
| MetadatakeyEventType = "eventtype" | ||
| ) | ||
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| type ( | ||
| // Unmarshaller is the interface events need to fulfill | ||
| Unmarshaller interface { | ||
| Unmarshal([]byte) (interface{}, error) | ||
| } | ||
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| // Publisher is the interface publishers need to fulfill | ||
| Publisher interface { | ||
| Publish(string, interface{}, ...events.PublishOption) error | ||
| } | ||
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| // Consumer is the interface consumer need to fulfill | ||
| Consumer interface { | ||
| Consume(string, ...events.ConsumeOption) (<-chan events.Event, error) | ||
| } | ||
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| // Stream is the interface common to Publisher and Consumer | ||
| Stream interface { | ||
| Publish(string, interface{}, ...events.PublishOption) error | ||
| Consume(string, ...events.ConsumeOption) (<-chan events.Event, error) | ||
| } | ||
| ) | ||
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| // Consume returns a channel that will get all events that match the given evs | ||
| // group defines the service type: One group will get exactly one copy of a event that is emitted | ||
| // NOTE: uses reflect on initialization | ||
| func Consume(s Consumer, group string, evs ...Unmarshaller) (<-chan interface{}, error) { | ||
| c, err := s.Consume(MainQueueName, events.WithGroup(group)) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
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| registeredEvents := map[string]Unmarshaller{} | ||
| for _, e := range evs { | ||
| typ := reflect.TypeOf(e) | ||
| registeredEvents[typ.String()] = e | ||
| } | ||
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| outchan := make(chan interface{}) | ||
| go func() { | ||
| for { | ||
| e := <-c | ||
| et := e.Metadata[MetadatakeyEventType] | ||
| ev, ok := registeredEvents[et] | ||
| if !ok { | ||
| log.Printf("not registered: %s", et) | ||
| continue | ||
| } | ||
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| event, err := ev.Unmarshal(e.Payload) | ||
| if err != nil { | ||
| log.Printf("can't unmarshal event %v", err) | ||
| continue | ||
| } | ||
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| outchan <- event | ||
| } | ||
| }() | ||
| return outchan, nil | ||
| } | ||
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| // Publish publishes the ev to the MainQueue from where it is distributed to all subscribers | ||
| // NOTE: needs to use reflect on runtime | ||
| func Publish(s Publisher, ev interface{}) error { | ||
| evName := reflect.TypeOf(ev).String() | ||
| return s.Publish(MainQueueName, ev, events.WithMetadata(map[string]string{ | ||
| MetadatakeyEventType: evName, | ||
| })) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,60 @@ | ||
| // Copyright 2018-2021 CERN | ||
| // | ||
| // 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. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
| // | ||
| // In applying this license, CERN does not waive the privileges and immunities | ||
| // granted to it by virtue of its status as an Intergovernmental Organization | ||
| // or submit itself to any jurisdiction. | ||
|
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| // Package consumer contains an example implementation of an event consumer | ||
| package consumer | ||
|
|
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| import ( | ||
| "fmt" | ||
| "log" | ||
|
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| "github.com/cs3org/reva/pkg/events" | ||
| ) | ||
|
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| // Example consumes events from the queue | ||
| func Example(c events.Consumer) { | ||
| // Step 1 - which group does the consumer belong to? | ||
| // each group will get each event that is emitted, but only one member of the group will get it. | ||
| group := "test-consumer" | ||
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| // Step 2 - which events does the consumer listen too? | ||
| evs := []events.Unmarshaller{ | ||
| // for example created shares | ||
| events.ShareCreated{}, | ||
| } | ||
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| // Step 3 - create event channel | ||
| evChan, err := events.Consume(c, group, evs...) | ||
| if err != nil { | ||
| log.Fatal(err) | ||
| } | ||
|
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| // Step 4 - listen to events | ||
| for { | ||
| event := <-evChan | ||
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| // best to use type switch to differentiate events | ||
| switch v := event.(type) { | ||
| case events.ShareCreated: | ||
| fmt.Printf("%s) Share created: %+v\n", group, v) | ||
| default: | ||
| fmt.Printf("%s) Unregistered event: %+v\n", group, v) | ||
| } | ||
| } | ||
|
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| } |
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