Some minor refactoring of azcore (#20291)

Moved ARM resource ID types and helpers to an internal package so they
can be leveraged elsewhere.  The public versions are type-aliased to the
matching internal implementations.
policyFunc has moved to the shared package so it can be used elsewhere.
Sanitizing of URLs has been split into its own function.
Moved a func-local constant to the shared package.

sdk/azcore/arm/internal/resource/resource_identifier.go

@@ -0,0 +1,224 @@
+//go:build go1.18
+// +build go1.18
+
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package resource
+
+import (
+	"fmt"
+	"strings"
+)
+
+const (
+	providersKey             = "providers"
+	subscriptionsKey         = "subscriptions"
+	resourceGroupsLowerKey   = "resourcegroups"
+	locationsKey             = "locations"
+	builtInResourceNamespace = "Microsoft.Resources"
+)
+
+// RootResourceID defines the tenant as the root parent of all other ResourceID.
+var RootResourceID = &ResourceID{
+	Parent:       nil,
+	ResourceType: TenantResourceType,
+	Name:         "",
+}
+
+// ResourceID represents a resource ID such as `/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/myRg`.
+// Don't create this type directly, use ParseResourceID instead.
+type ResourceID struct {
+	// Parent is the parent ResourceID of this instance.
+	// Can be nil if there is no parent.
+	Parent *ResourceID
+
+	// SubscriptionID is the subscription ID in this resource ID.
+	// The value can be empty if the resource ID does not contain a subscription ID.
+	SubscriptionID string
+
+	// ResourceGroupName is the resource group name in this resource ID.
+	// The value can be empty if the resource ID does not contain a resource group name.
+	ResourceGroupName string
+
+	// Provider represents the provider name in this resource ID.
+	// This is only valid when the resource ID represents a resource provider.
+	// Example: `/subscriptions/00000000-0000-0000-0000-000000000000/providers/Microsoft.Insights`
+	Provider string
+
+	// Location is the location in this resource ID.
+	// The value can be empty if the resource ID does not contain a location name.
+	Location string
+
+	// ResourceType represents the type of this resource ID.
+	ResourceType ResourceType
+
+	// Name is the resource name of this resource ID.
+	Name string
+
+	isChild     bool
+	stringValue string
+}
+
+// ParseResourceID parses a string to an instance of ResourceID
+func ParseResourceID(id string) (*ResourceID, error) {
+	if len(id) == 0 {
+		return nil, fmt.Errorf("invalid resource ID: id cannot be empty")
+	}
+
+	if !strings.HasPrefix(id, "/") {
+		return nil, fmt.Errorf("invalid resource ID: resource id '%s' must start with '/'", id)
+	}
+
+	parts := splitStringAndOmitEmpty(id, "/")
+
+	if len(parts) < 2 {
+		return nil, fmt.Errorf("invalid resource ID: %s", id)
+	}
+
+	if !strings.EqualFold(parts[0], subscriptionsKey) && !strings.EqualFold(parts[0], providersKey) {
+		return nil, fmt.Errorf("invalid resource ID: %s", id)
+	}
+
+	return appendNext(RootResourceID, parts, id)
+}
+
+// String returns the string of the ResourceID
+func (id *ResourceID) String() string {
+	if len(id.stringValue) > 0 {
+		return id.stringValue
+	}
+
+	if id.Parent == nil {
+		return ""
+	}
+
+	builder := strings.Builder{}
+	builder.WriteString(id.Parent.String())
+
+	if id.isChild {
+		builder.WriteString(fmt.Sprintf("/%s", id.ResourceType.lastType()))
+		if len(id.Name) > 0 {
+			builder.WriteString(fmt.Sprintf("/%s", id.Name))
+		}
+	} else {
+		builder.WriteString(fmt.Sprintf("/providers/%s/%s/%s", id.ResourceType.Namespace, id.ResourceType.Type, id.Name))
+	}
+
+	id.stringValue = builder.String()
+
+	return id.stringValue
+}
+
+func newResourceID(parent *ResourceID, resourceTypeName string, resourceName string) *ResourceID {
+	id := &ResourceID{}
+	id.init(parent, chooseResourceType(resourceTypeName, parent), resourceName, true)
+	return id
+}
+
+func newResourceIDWithResourceType(parent *ResourceID, resourceType ResourceType, resourceName string) *ResourceID {
+	id := &ResourceID{}
+	id.init(parent, resourceType, resourceName, true)
+	return id
+}
+
+func newResourceIDWithProvider(parent *ResourceID, providerNamespace, resourceTypeName, resourceName string) *ResourceID {
+	id := &ResourceID{}
+	id.init(parent, NewResourceType(providerNamespace, resourceTypeName), resourceName, false)
+	return id
+}
+
+func chooseResourceType(resourceTypeName string, parent *ResourceID) ResourceType {
+	if strings.EqualFold(resourceTypeName, resourceGroupsLowerKey) {
+		return ResourceGroupResourceType
+	} else if strings.EqualFold(resourceTypeName, subscriptionsKey) && parent != nil && parent.ResourceType.String() == TenantResourceType.String() {
+		return SubscriptionResourceType
+	}
+
+	return parent.ResourceType.AppendChild(resourceTypeName)
+}
+
+func (id *ResourceID) init(parent *ResourceID, resourceType ResourceType, name string, isChild bool) {
+	if parent != nil {
+		id.Provider = parent.Provider
+		id.SubscriptionID = parent.SubscriptionID
+		id.ResourceGroupName = parent.ResourceGroupName
+		id.Location = parent.Location
+	}
+
+	if resourceType.String() == SubscriptionResourceType.String() {
+		id.SubscriptionID = name
+	}
+
+	if resourceType.lastType() == locationsKey {
+		id.Location = name
+	}
+
+	if resourceType.String() == ResourceGroupResourceType.String() {
+		id.ResourceGroupName = name
+	}
+
+	if resourceType.String() == ProviderResourceType.String() {
+		id.Provider = name
+	}
+
+	if parent == nil {
+		id.Parent = RootResourceID
+	} else {
+		id.Parent = parent
+	}
+	id.isChild = isChild
+	id.ResourceType = resourceType
+	id.Name = name
+}
+
+func appendNext(parent *ResourceID, parts []string, id string) (*ResourceID, error) {
+	if len(parts) == 0 {
+		return parent, nil
+	}
+
+	if len(parts) == 1 {
+		// subscriptions and resourceGroups are not valid ids without their names
+		if strings.EqualFold(parts[0], subscriptionsKey) || strings.EqualFold(parts[0], resourceGroupsLowerKey) {
+			return nil, fmt.Errorf("invalid resource ID: %s", id)
+		}
+
+		// resourceGroup must contain either child or provider resource type
+		if parent.ResourceType.String() == ResourceGroupResourceType.String() {
+			return nil, fmt.Errorf("invalid resource ID: %s", id)
+		}
+
+		return newResourceID(parent, parts[0], ""), nil
+	}
+
+	if strings.EqualFold(parts[0], providersKey) && (len(parts) == 2 || strings.EqualFold(parts[2], providersKey)) {
+		//provider resource can only be on a tenant or a subscription parent
+		if parent.ResourceType.String() != SubscriptionResourceType.String() && parent.ResourceType.String() != TenantResourceType.String() {
+			return nil, fmt.Errorf("invalid resource ID: %s", id)
+		}
+
+		return appendNext(newResourceIDWithResourceType(parent, ProviderResourceType, parts[1]), parts[2:], id)
+	}
+
+	if len(parts) > 3 && strings.EqualFold(parts[0], providersKey) {
+		return appendNext(newResourceIDWithProvider(parent, parts[1], parts[2], parts[3]), parts[4:], id)
+	}
+
+	if len(parts) > 1 && !strings.EqualFold(parts[0], providersKey) {
+		return appendNext(newResourceID(parent, parts[0], parts[1]), parts[2:], id)
+	}
+
+	return nil, fmt.Errorf("invalid resource ID: %s", id)
+}
+
+func splitStringAndOmitEmpty(v, sep string) []string {
+	r := make([]string, 0)
+	for _, s := range strings.Split(v, sep) {
+		if len(s) == 0 {
+			continue
+		}
+		r = append(r, s)
+	}
+
+	return r
+}

sdk/azcore/arm/resource_identifier_test.go → sdk/azcore/arm/internal/resource/resource_identifier_test.go

@@ -4,7 +4,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-package arm
+package resource
 
 import "testing"
 

sdk/azcore/arm/internal/resource/resource_type.go

@@ -0,0 +1,114 @@
+//go:build go1.18
+// +build go1.18
+
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+package resource
+
+import (
+	"fmt"
+	"strings"
+)
+
+// SubscriptionResourceType is the ResourceType of a subscription
+var SubscriptionResourceType = NewResourceType(builtInResourceNamespace, "subscriptions")
+
+// ResourceGroupResourceType is the ResourceType of a resource group
+var ResourceGroupResourceType = NewResourceType(builtInResourceNamespace, "resourceGroups")
+
+// TenantResourceType is the ResourceType of a tenant
+var TenantResourceType = NewResourceType(builtInResourceNamespace, "tenants")
+
+// ProviderResourceType is the ResourceType of a provider
+var ProviderResourceType = NewResourceType(builtInResourceNamespace, "providers")
+
+// ResourceType represents an Azure resource type, e.g. "Microsoft.Network/virtualNetworks/subnets".
+// Don't create this type directly, use ParseResourceType or NewResourceType instead.
+type ResourceType struct {
+	// Namespace is the namespace of the resource type.
+	// e.g. "Microsoft.Network" in resource type "Microsoft.Network/virtualNetworks/subnets"
+	Namespace string
+
+	// Type is the full type name of the resource type.
+	// e.g. "virtualNetworks/subnets" in resource type "Microsoft.Network/virtualNetworks/subnets"
+	Type string
+
+	// Types is the slice of all the sub-types of this resource type.
+	// e.g. ["virtualNetworks", "subnets"] in resource type "Microsoft.Network/virtualNetworks/subnets"
+	Types []string
+
+	stringValue string
+}
+
+// String returns the string of the ResourceType
+func (t ResourceType) String() string {
+	return t.stringValue
+}
+
+// IsParentOf returns true when the receiver is the parent resource type of the child.
+func (t ResourceType) IsParentOf(child ResourceType) bool {
+	if !strings.EqualFold(t.Namespace, child.Namespace) {
+		return false
+	}
+	if len(t.Types) >= len(child.Types) {
+		return false
+	}
+	for i := range t.Types {
+		if !strings.EqualFold(t.Types[i], child.Types[i]) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// AppendChild creates an instance of ResourceType using the receiver as the parent with childType appended to it.
+func (t ResourceType) AppendChild(childType string) ResourceType {
+	return NewResourceType(t.Namespace, fmt.Sprintf("%s/%s", t.Type, childType))
+}
+
+// NewResourceType creates an instance of ResourceType using a provider namespace
+// such as "Microsoft.Network" and type such as "virtualNetworks/subnets".
+func NewResourceType(providerNamespace, typeName string) ResourceType {
+	return ResourceType{
+		Namespace:   providerNamespace,
+		Type:        typeName,
+		Types:       splitStringAndOmitEmpty(typeName, "/"),
+		stringValue: fmt.Sprintf("%s/%s", providerNamespace, typeName),
+	}
+}
+
+// ParseResourceType parses the ResourceType from a resource type string (e.g. Microsoft.Network/virtualNetworks/subsets)
+// or a resource identifier string.
+// e.g. /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/myRg/providers/Microsoft.Network/virtualNetworks/vnet/subnets/mySubnet)
+func ParseResourceType(resourceIDOrType string) (ResourceType, error) {
+	// split the path into segments
+	parts := splitStringAndOmitEmpty(resourceIDOrType, "/")
+
+	// There must be at least a namespace and type name
+	if len(parts) < 1 {
+		return ResourceType{}, fmt.Errorf("invalid resource ID or type: %s", resourceIDOrType)
+	}
+
+	// if the type is just subscriptions, it is a built-in type in the Microsoft.Resources namespace
+	if len(parts) == 1 {
+		// Simple resource type
+		return NewResourceType(builtInResourceNamespace, parts[0]), nil
+	} else if strings.Contains(parts[0], ".") {
+		// Handle resource types (Microsoft.Compute/virtualMachines, Microsoft.Network/virtualNetworks/subnets)
+		// it is a full type name
+		return NewResourceType(parts[0], strings.Join(parts[1:], "/")), nil
+	} else {
+		// Check if ResourceID
+		id, err := ParseResourceID(resourceIDOrType)
+		if err != nil {
+			return ResourceType{}, err
+		}
+		return NewResourceType(id.ResourceType.Namespace, id.ResourceType.Type), nil
+	}
+}
+
+func (t ResourceType) lastType() string {
+	return t.Types[len(t.Types)-1]
+}

sdk/azcore/arm/resource_type_test.go → sdk/azcore/arm/internal/resource/resource_type_test.go

@@ -4,7 +4,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-package arm
+package resource
 
 import (
 	"testing"