refactor aggregate package (#9)

* rename advanced aggregate to EventSourced
* change aggregate factory to get rid of extra dependencies
* update tests with better examples and test case names
* provide excessive documentation and examples

.golangci.yml

@@ -31,10 +31,9 @@ linters:
     - durationcheck
     - errcheck
     - errchkjson
-    #- errname
+    - errname
     - errorlint
     - execinquery
-    #- errorsas
     - exhaustive
     - exportloopref
     #- forbidigo
@@ -68,7 +67,7 @@ linters:
     #- ireturn
     - ineffassign
     - lll
-    #- logrlint
+    - logrlint
     - maintidx
     - makezero
     - misspell
@@ -80,7 +79,7 @@ linters:
     - nolintlint
     - nonamedreturns
     - nosprintfhostport
-    #- paralleltest
+    - paralleltest
     - prealloc
     - predeclared
     - promlinter
@@ -94,7 +93,7 @@ linters:
     - tenv
     - testpackage
     - thelper
-    #- tparallel
+    - tparallel
     - typecheck
     - unconvert
     - unparam

Makefile

@@ -24,13 +24,17 @@ tools: ## install dev tools, linters, code generators, etc..
 	@echo -e "$(OK_COLOR)--> Installing tools from tools/tools.go$(NO_COLOR)"
 	@export GOBIN=$$PWD/tools/bin; export PATH=$$GOBIN:$$PATH; cat tools/tools.go | grep _ | awk -F'"' '{print $$2}' | xargs -tI % go install %
 
-lint: ## run linters
+lint: ## run linters for the current changes
 	@echo -e "$(OK_COLOR)--> Running linters$(NO_COLOR)"
 	@tools/bin/golangci-lint run
 
+lint-all: ## run linters
+	@echo -e "$(OK_COLOR)==> Linting$(NO_COLOR)"
+	golangci-lint run ./... --new-from-rev=""
+
 test: ## run  tests
 	@echo -e "$(OK_COLOR)--> Running unit tests$(NO_COLOR)"
-	go test -v --race --count=1 -coverprofile=coverage.tmp ./...
+	go test -v --race --count=1 -covermode atomic -coverprofile=coverage.tmp ./...
 	@set -euo pipefail && cat coverage.tmp | grep -v $(IGNORE_COVERAGE_FOR) > coverage.out && rm coverage.tmp
 
 coverage: test ## show test coverage report
@@ -55,4 +59,4 @@ help: ## show this help screen
 # To avoid unintended conflicts with file names, always add to .PHONY
 # unless there is a reason not to.
 # https://www.gnu.org/software/make/manual/html_node/Phony-Targets.html
-.PHONY: all deps tools lint test coverage fmt clean help
+.PHONY: all deps tools lint lint-all test coverage fmt clean help

aggregate/aggregate.go

@@ -0,0 +1,35 @@
+// Package aggregate provides a base implementation for event sourced aggregates.
+//
+// To create an event sourced aggregate, a user must define their own domain
+// aggregate that implements the cqrs.Aggregate interface. The user's domain
+// aggregate should define its own identifier type and event type.
+//
+// Additionally, command handlers and event appliers should be defined within
+// the user's domain aggregate. The command handlers handle commands and produce
+// events, while the event appliers apply events to update the aggregate's state.
+//
+// Once the user's domain aggregate is defined, it can be transformed into
+// a cqrs.ESAggregate using the aggregate.FromAggregate function. This function
+// automatically registers the command handlers and event appliers defined in
+// the user's domain aggregate.
+//
+// For a detailed example of how to use the aggregate package, please refer to
+// the Example function in the example_test.go file.
+//
+// More examples can be found in the examples directory.
+package aggregate
+
+import (
+	"errors"
+)
+
+var (
+	// ErrCommandHandlerNotFound is returned when a command handler is not found.
+	ErrCommandHandlerNotFound = errors.New("command handler not found")
+
+	// ErrEventApplierNotFound is returned when an event applier is not found.
+	ErrEventApplierNotFound = errors.New("event applier not found")
+
+	// ErrAggregateNotRegistered is returned when an aggregate is not registered in the factory.
+	ErrAggregateNotRegistered = errors.New("aggregate is not registered")
+)

aggregate/aggtest/aggregate.go

@@ -7,11 +7,9 @@ import (
 )
 
 var (
-	ErrItCanHappenOnceOnly                = errors.New("some business rule error occurred")
-	ErrMakeSomethingHandlerNotFound       = errors.New("handler for MakeSomethingHappen command is not found")
-	ErrOnSomethingHappenedApplierNotFound = errors.New("event applier for OnSomethingHappened event is not found")
+	ErrItCanHappenOnceOnly = errors.New("some business rule error occurred")
 
-	TestAggregateType = "mock.TestAggregate"
+	TestAggregateType = "mock.TestAggregate" //nolint:gochecknoglobals
 )
 
 type StringIdentifier string
@@ -20,40 +18,39 @@ func (i StringIdentifier) String() string {
 	return string(i)
 }
 
-// TestAggregate a pure aggregate (has no external dependencies or dark magic method) used for testing.
+// TestAggregate is a user-defined aggregate (has no external dependencies or dark magic methods) used for testing.
 type TestAggregate struct {
-	id      cqrs.Identifier
-	version int
-	aggType string
+	id Identifier
 
 	alreadyHappened bool
 }
 
 // NewTestAggregate creates a new instance of TestAggregate.
-func NewTestAggregate(ID cqrs.Identifier) *TestAggregate {
-	return &TestAggregate{id: ID}
+func NewTestAggregate(id cqrs.Identifier) *TestAggregate {
+	return &TestAggregate{id: id}
 }
 
 // AggregateID implements cqrs.Aggregate interface.
-func (a *TestAggregate) AggregateID() cqrs.Identifier {
+func (a *TestAggregate) AggregateID() Identifier {
 	return a.id
 }
 
 // AggregateType implements cqrs.Aggregate interface.
 func (a *TestAggregate) AggregateType() string {
-	return "mock.TestAggregate"
+	return TestAggregateType
 }
 
-func (a *TestAggregate) MakeSomethingHappen(c MakeSomethingHappen) ([]cqrs.DomainEvent, error) {
+func (a *TestAggregate) MakeSomethingHappen(_ MakeSomethingHappen) ([]Event, error) {
 	if a.alreadyHappened {
 		return nil, ErrItCanHappenOnceOnly
 	}
-	return []cqrs.DomainEvent{SomethingHappened{}}, nil
+
+	return []Event{SomethingHappened{}}, nil
 }
 
-func (a *TestAggregate) OnSomethingHappened(e SomethingHappened) {
+func (a *TestAggregate) OnSomethingHappened(_ SomethingHappened) {
 	a.alreadyHappened = true
 }
 
-func (a *TestAggregate) OnSomethingElseHappened(e SomethingElseHappened) {
+func (a *TestAggregate) OnSomethingElseHappened(_ SomethingElseHappened) {
 }