Basic CHASM registry implementation (#7184)

## What changed?
<!-- Describe what has changed in this PR -->
Added basic CHASM registry implementation.

## Why?
<!-- Tell your future self why have you made these changes -->
CHASM project.

## How did you test it?
<!-- How have you verified this change? Tested locally? Added a unit
test? Checked in staging env? -->
Added new unit tests. `registry.go` has 100% coverage.

## Potential risks
<!-- Assuming the worst case, what can be broken when deploying this
change to production? -->
No risks.

## Documentation
<!-- Have you made sure this change doesn't falsify anything currently
stated in `docs/`? If significant
new behavior is added, have you described that in `docs/`? -->
Not yet.

## Is hotfix candidate?
<!-- Is this PR a hotfix candidate or does it require a notification to
be sent to the broader community? (Yes/No) -->
No.

chasm/component.go

@@ -22,6 +22,8 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
+//go:generate mockgen -copyright_file ../LICENSE -package $GOPACKAGE -source $GOFILE -destination component_mock.go
+
 package chasm
 
 import "context"

chasm/export_test.go

@@ -0,0 +1,41 @@
+// The MIT License
+//
+// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
+//
+// Copyright (c) 2020 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package chasm
+
+func (r *Registry) Component(fqn string) (*RegistrableComponent, bool) {
+	return r.component(fqn)
+}
+
+func (r *Registry) Task(fqn string) (*RegistrableTask, bool) {
+	return r.task(fqn)
+}
+
+func (r *Registry) ComponentFor(componentInstance any) (*RegistrableComponent, bool) {
+	return r.componentFor(componentInstance)
+}
+
+func (r *Registry) TaskFor(taskInstance any) (*RegistrableTask, bool) {
+	return r.taskFor(taskInstance)
+}

chasm/library.go

@@ -0,0 +1,50 @@
+// The MIT License
+//
+// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
+//
+// Copyright (c) 2020 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+//go:generate mockgen -copyright_file ../LICENSE -package $GOPACKAGE -source $GOFILE -destination library_mock.go
+
+package chasm
+
+type (
+	Library interface {
+		Name() string
+		Components() []*RegistrableComponent
+		Tasks() []*RegistrableTask
+		// Service()
+
+		mustEmbedUnimplementedLibrary()
+	}
+
+	UnimplementedLibrary struct{}
+)
+
+func (UnimplementedLibrary) Components() []*RegistrableComponent {
+	return nil
+}
+
+func (UnimplementedLibrary) Tasks() []*RegistrableTask {
+	return nil
+}
+
+func (UnimplementedLibrary) mustEmbedUnimplementedLibrary() {}

chasm/ref.go

@@ -28,6 +28,10 @@ import (
 	persistencespb "go.temporal.io/server/api/persistence/v1"
 )
 
+var (
+	defaultShardingFn = func(key EntityKey) string { return key.NamespaceID + "_" + key.EntityID }
+)
+
 type EntityKey struct {
 	NamespaceID string
 	BusinessID  string