From 3f4a72354177175eea7d5ef98c3e06d09ebd1bfd Mon Sep 17 00:00:00 2001
From: Timothy Messier <tim.messier@gmail.com>
Date: Mon, 9 Oct 2023 19:36:51 +0000
Subject: [PATCH] feat(action): Add registrar for valid actions by resource

---
 internal/types/action/registrar.go          | 73 +++++++++++++++++++++
 internal/types/action/registrar_ext_test.go | 71 ++++++++++++++++++++
 2 files changed, 144 insertions(+)
 create mode 100644 internal/types/action/registrar.go
 create mode 100644 internal/types/action/registrar_ext_test.go

diff --git a/internal/types/action/registrar.go b/internal/types/action/registrar.go
new file mode 100644
index 0000000000..310079f4eb
--- /dev/null
+++ b/internal/types/action/registrar.go
@@ -0,0 +1,73 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package action
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/hashicorp/boundary/internal/types/resource"
+)
+
+type resourceActionSets struct {
+	individual ActionSet
+	collection ActionSet
+	valid      ActionSet
+}
+
+type byResource struct {
+	mu sync.RWMutex
+	m  map[resource.Type]*resourceActionSets
+}
+
+func (b *byResource) add(r resource.Type, individual ActionSet, collection ActionSet) error {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+
+	if b.m == nil {
+		b.m = make(map[resource.Type]*resourceActionSets)
+	}
+
+	_, ok := b.m[r]
+	if ok {
+		return fmt.Errorf("%s already registered", r)
+	}
+	b.m[r] = &resourceActionSets{
+		individual: individual,
+		collection: collection,
+		valid:      Union(individual, collection),
+	}
+
+	return nil
+}
+
+func (b *byResource) get(r resource.Type) (*resourceActionSets, error) {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	a, ok := b.m[r]
+	if !ok {
+		return nil, fmt.Errorf("resource not found: %s", r)
+	}
+	return a, nil
+}
+
+var byResourceRegistrar = &byResource{}
+
+// RegisterResource registers ActionSets for r. If RegisterResource is called
+// twice with the same resource, it panics.
+func RegisterResource(r resource.Type, individual ActionSet, collection ActionSet) {
+	if err := byResourceRegistrar.add(r, individual, collection); err != nil {
+		panic(err)
+	}
+}
+
+// ActionSetForResource returns the ActionSet registered for r
+// or an error if r has not been registered.
+func ActionSetForResource(r resource.Type) (ActionSet, error) {
+	a, err := byResourceRegistrar.get(r)
+	if err != nil {
+		return nil, err
+	}
+	return a.valid, nil
+}
diff --git a/internal/types/action/registrar_ext_test.go b/internal/types/action/registrar_ext_test.go
new file mode 100644
index 0000000000..9c42f6a76e
--- /dev/null
+++ b/internal/types/action/registrar_ext_test.go
@@ -0,0 +1,71 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package action_test
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/hashicorp/boundary/internal/types/action"
+	"github.com/hashicorp/boundary/internal/types/resource"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRegisterResource(t *testing.T) {
+	t.Run("Pancis", func(t *testing.T) {
+		// Ensure the resource is not registered yet
+		_, err := action.ActionSetForResource(resource.Session)
+		require.EqualError(t, err, "resource not found: session")
+
+		// Now register the resource
+		action.RegisterResource(resource.Session, action.NewActionSet(action.Read, action.Create), action.NewActionSet(action.List))
+		got, err := action.ActionSetForResource(resource.Session)
+		require.NoError(t, err)
+		assert.Equal(t, action.NewActionSet(action.Read, action.Create, action.List), got)
+
+		// Attempting to register the same resource again should panic
+		require.Panics(
+			t,
+			func() {
+				action.RegisterResource(resource.Session, action.NewActionSet(action.Update, action.Read, action.Create), action.NewActionSet(action.List))
+			},
+		)
+	})
+
+	// Run these after the Pancis test rely on resource.Session already being registered.
+	t.Run("ActionSetForResource", func(t *testing.T) {
+		cases := []struct {
+			name    string
+			res     resource.Type
+			want    action.ActionSet
+			wantErr error
+		}{
+			{
+				"NotRegistered",
+				resource.Target,
+				nil,
+				errors.New("resource not found: target"),
+			},
+			{
+				"Registered",
+				resource.Session,
+				action.NewActionSet(action.Read, action.Create, action.List),
+				nil,
+			},
+		}
+		for _, tc := range cases {
+			t.Run(tc.name, func(t *testing.T) {
+				got, err := action.ActionSetForResource(tc.res)
+				if tc.wantErr != nil {
+					require.EqualError(t, err, tc.wantErr.Error())
+					return
+				}
+
+				require.NoError(t, err)
+				assert.Equal(t, tc.want, got)
+			})
+		}
+	})
+}