12622512440

Committed 05 Jan 2025 07:58PM UTC coverage: 27.495% (-39.9%) from 67.361%

Build # 12622512440

Build Type

Pull #419

github

Committed by

web-flow

Commit Message

Merge b3c17d928 into ac3a97277

Pull Request Pull Request #419: fix(ci): update to up/download-artifact v4

Run Details

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0.0

/eventhandler/saga/eventhandler.go

// Copyright (c) 2016 - The Event Horizon authors.
//
// 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.

package saga

import (
        "context"
        "fmt"

        eh "github.com/looplab/eventhorizon"
)

// EventHandler is a CQRS saga handler to run a Saga implementation.
type EventHandler struct {
        saga           Saga
        commandHandler eh.CommandHandler
}

var _ = eh.EventHandler(&EventHandler{})

// Saga is an interface for a CQRS saga that listens to events and generate
// commands. It is used for any long lived transaction and can be used to react
// on multiple events.
type Saga interface {
        // SagaType returns the type of the saga.
        SagaType() Type

        // RunSaga handles an event in the saga that can return commands.
        // If an error is returned from the saga, the event will be run again.
        RunSaga(context.Context, eh.Event, eh.CommandHandler) error
}

// Type is the type of a saga, used as its unique identifier.
type Type string

// String returns the string representation of a saga type.
func (t Type) String() string {
        return string(t)
}

// Error is an error in the projector.
type Error struct {
        // Err is the error that happened when projecting the event.
        Err error
        // Saga is the saga where the error happened.
        Saga string
}

// Error implements the Error method of the errors.Error interface.
func (e *Error) Error() string {
        return fmt.Sprintf("%s: %s", e.Saga, e.Err)
}

// Unwrap implements the errors.Unwrap method.
func (e *Error) Unwrap() error {
        return e.Err
}

// Cause implements the github.com/pkg/errors Unwrap method.
func (e *Error) Cause() error {
        return e.Unwrap()
}

// NewEventHandler creates a new EventHandler.
func NewEventHandler(saga Saga, commandHandler eh.CommandHandler) *EventHandler {
        return &EventHandler{
                saga:           saga,
                commandHandler: commandHandler,
        }
}

// HandlerType implements the HandlerType method of the eventhorizon.EventHandler interface.
func (h *EventHandler) HandlerType() eh.EventHandlerType {
        return eh.EventHandlerType("saga_" + h.saga.SagaType())
}

// HandleEvent implements the HandleEvent method of the eventhorizon.EventHandler interface.
func (h *EventHandler) HandleEvent(ctx context.Context, event eh.Event) error {
        if event == nil {
                return &Error{
                        Err:  eh.ErrMissingEvent,
                        Saga: h.saga.SagaType().String(),
                }
        }

        // Run the saga which can issue commands on the provided command handler.
        if err := h.saga.RunSaga(ctx, event, h.commandHandler); err != nil {
                return &Error{
                        Err:  err,
                        Saga: h.saga.SagaType().String(),
                }
        }

        return nil
}

1	// Copyright (c) 2016 - The Event Horizon authors.
2	//
3	// Licensed under the Apache License, Version 2.0 (the "License");
4	// you may not use this file except in compliance with the License.
5	// You may obtain a copy of the License at
6	//
7	// http://www.apache.org/licenses/LICENSE-2.0
8	//
9	// Unless required by applicable law or agreed to in writing, software
10	// distributed under the License is distributed on an "AS IS" BASIS,
11	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12	// See the License for the specific language governing permissions and
13	// limitations under the License.
14
15	package saga
16
17	import (
18	"context"
19	"fmt"
20
21	eh "github.com/looplab/eventhorizon"
22	)
23
24	// EventHandler is a CQRS saga handler to run a Saga implementation.
25	type EventHandler struct {
26	saga Saga
27	commandHandler eh.CommandHandler
28	}
29
30	var _ = eh.EventHandler(&EventHandler{})
31
32	// Saga is an interface for a CQRS saga that listens to events and generate
33	// commands. It is used for any long lived transaction and can be used to react
34	// on multiple events.
35	type Saga interface {
36	// SagaType returns the type of the saga.
37	SagaType() Type
38
39	// RunSaga handles an event in the saga that can return commands.
40	// If an error is returned from the saga, the event will be run again.
41	RunSaga(context.Context, eh.Event, eh.CommandHandler) error
42	}
43
44	// Type is the type of a saga, used as its unique identifier.
45	type Type string
46
47	// String returns the string representation of a saga type.
48	func (t Type) String() string {	×
49	return string(t)	×
50	}	×
51
52	// Error is an error in the projector.
53	type Error struct {
54	// Err is the error that happened when projecting the event.
55	Err error
56	// Saga is the saga where the error happened.
57	Saga string
58	}
59
60	// Error implements the Error method of the errors.Error interface.
61	func (e *Error) Error() string {	×
62	return fmt.Sprintf("%s: %s", e.Saga, e.Err)	×
63	}	×
64
65	// Unwrap implements the errors.Unwrap method.
66	func (e *Error) Unwrap() error {	×
67	return e.Err	×
68	}	×
69
70	// Cause implements the github.com/pkg/errors Unwrap method.
71	func (e *Error) Cause() error {	×
72	return e.Unwrap()	×
73	}	×
74
75	// NewEventHandler creates a new EventHandler.
76	func NewEventHandler(saga Saga, commandHandler eh.CommandHandler) *EventHandler {	×
77	return &EventHandler{	×
78	saga: saga,	×
79	commandHandler: commandHandler,	×
80	}	×
81	}	×
82
83	// HandlerType implements the HandlerType method of the eventhorizon.EventHandler interface.
84	func (h *EventHandler) HandlerType() eh.EventHandlerType {	×
85	return eh.EventHandlerType("saga_" + h.saga.SagaType())	×
86	}	×
87
88	// HandleEvent implements the HandleEvent method of the eventhorizon.EventHandler interface.
89	func (h *EventHandler) HandleEvent(ctx context.Context, event eh.Event) error {	×
90	if event == nil {	×
91	return &Error{	×
92	Err: eh.ErrMissingEvent,	×
93	Saga: h.saga.SagaType().String(),	×
94	}	×
95	}	×
96
97	// Run the saga which can issue commands on the provided command handler.
98	if err := h.saga.RunSaga(ctx, event, h.commandHandler); err != nil {	×
99	return &Error{	×
100	Err: err,	×
101	Saga: h.saga.SagaType().String(),	×
102	}	×
103	}	×
104
105	return nil	×
106	}

looplab / eventhorizon / 12622512440

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