mgmt.go

package servicebus

//	MIT License
//
//	Copyright (c) Microsoft Corporation. All rights reserved.
//
//	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

import (
	"bytes"
	"context"
	"encoding/xml"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/http/httputil"
	"strings"
	"time"

	"github.com/Azure/azure-amqp-common-go/v3/auth"
	"github.com/devigned/tab"
)

const (
	serviceBusSchema = "http://schemas.microsoft.com/netservices/2010/10/servicebus/connect"
	schemaInstance   = "http://www.w3.org/2001/XMLSchema-instance"
	atomSchema       = "http://www.w3.org/2005/Atom"
	applicationXML   = "application/xml"
)

type (
	// entityManager provides CRUD functionality for Service Bus entities (Queues, Topics, Subscriptions...)
	entityManager struct {
		tokenProvider auth.TokenProvider
		Host          string
		mwStack       []MiddlewareFunc
	}

	// BaseEntityDescription provides common fields which are part of Queues, Topics and Subscriptions
	BaseEntityDescription struct {
		InstanceMetadataSchema *string `xml:"xmlns:i,attr,omitempty"`
		ServiceBusSchema       *string `xml:"xmlns,attr,omitempty"`
	}

	managementError struct {
		XMLName xml.Name `xml:"Error"`
		Code    int      `xml:"Code"`
		Detail  string   `xml:"Detail"`
	}

	// CountDetails has current active (and other) messages for queue/topic.
	CountDetails struct {
		XMLName                        xml.Name `xml:"CountDetails"`
		ActiveMessageCount             *int32   `xml:"ActiveMessageCount,omitempty"`
		DeadLetterMessageCount         *int32   `xml:"DeadLetterMessageCount,omitempty"`
		ScheduledMessageCount          *int32   `xml:"ScheduledMessageCount,omitempty"`
		TransferDeadLetterMessageCount *int32   `xml:"TransferDeadLetterMessageCount,omitempty"`
		TransferMessageCount           *int32   `xml:"TransferMessageCount,omitempty"`
	}

	// EntityStatus enumerates the values for entity status.
	EntityStatus string

	// MiddlewareFunc allows a consumer of the entity manager to inject handlers within the request / response pipeline
	//
	// The example below adds the atom xml content type to the request, calls the next middleware and returns the
	// result.
	//
	// addAtomXMLContentType MiddlewareFunc = func(next RestHandler) RestHandler {
	//		return func(ctx context.Context, req *http.Request) (res *http.Response, e error) {
	//			if req.Method != http.MethodGet && req.Method != http.MethodHead {
	//				req.Header.Add("content-Type", "application/atom+xml;type=entry;charset=utf-8")
	//			}
	//			return next(ctx, req)
	//		}
	//	}
	MiddlewareFunc func(next RestHandler) RestHandler

	// RestHandler is used to transform a request and response within the http pipeline
	RestHandler func(ctx context.Context, req *http.Request) (*http.Response, error)
)

var (
	addAtomXMLContentType MiddlewareFunc = func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (res *http.Response, e error) {
			if req.Method != http.MethodGet && req.Method != http.MethodHead {
				req.Header.Add("content-Type", "application/atom+xml;type=entry;charset=utf-8")
			}
			return next(ctx, req)
		}
	}

	addAPIVersion201704 MiddlewareFunc = func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (*http.Response, error) {
			q := req.URL.Query()
			q.Add("api-version", "2017-04")
			req.URL.RawQuery = q.Encode()
			return next(ctx, req)
		}
	}

	applyTracing MiddlewareFunc = func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (*http.Response, error) {
			ctx, span := startConsumerSpanFromContext(ctx, "sb.Middleware.ApplyTracing")
			defer span.End()

			applyRequestInfo(span, req)
			res, err := next(ctx, req)
			applyResponseInfo(span, res)
			return res, err
		}
	}
)

const (
	// Active ...
	Active EntityStatus = "Active"
	// Creating ...
	Creating EntityStatus = "Creating"
	// Deleting ...
	Deleting EntityStatus = "Deleting"
	// Disabled ...
	Disabled EntityStatus = "Disabled"
	// ReceiveDisabled ...
	ReceiveDisabled EntityStatus = "ReceiveDisabled"
	// Renaming ...
	Renaming EntityStatus = "Renaming"
	// Restoring ...
	Restoring EntityStatus = "Restoring"
	// SendDisabled ...
	SendDisabled EntityStatus = "SendDisabled"
	// Unknown ...
	Unknown EntityStatus = "Unknown"
)

func (m *managementError) String() string {
	return fmt.Sprintf("Code: %d, Details: %s", m.Code, m.Detail)
}

// newEntityManager creates a new instance of an entityManager given a token provider and host
func newEntityManager(host string, tokenProvider auth.TokenProvider) *entityManager {
	return &entityManager{
		Host:          host,
		tokenProvider: tokenProvider,
		mwStack: []MiddlewareFunc{
			addAPIVersion201704,
			addAtomXMLContentType,
			addAuthorization(tokenProvider),
			applyTracing,
		},
	}
}

// Get performs an HTTP Get for a given entity path
func (em *entityManager) Get(ctx context.Context, entityPath string, mw ...MiddlewareFunc) (*http.Response, error) {
	ctx, span := em.startSpanFromContext(ctx, "sb.EntityManger.Get")
	defer span.End()

	return em.Execute(ctx, http.MethodGet, entityPath, http.NoBody, mw...)
}

// Put performs an HTTP PUT for a given entity path and body
func (em *entityManager) Put(ctx context.Context, entityPath string, body []byte, mw ...MiddlewareFunc) (*http.Response, error) {
	ctx, span := em.startSpanFromContext(ctx, "sb.EntityManger.Put")
	defer span.End()

	return em.Execute(ctx, http.MethodPut, entityPath, bytes.NewReader(body), mw...)
}

// Delete performs an HTTP DELETE for a given entity path
func (em *entityManager) Delete(ctx context.Context, entityPath string, mw ...MiddlewareFunc) (*http.Response, error) {
	ctx, span := em.startSpanFromContext(ctx, "sb.EntityManger.Delete")
	defer span.End()

	return em.Execute(ctx, http.MethodDelete, entityPath, http.NoBody, mw...)
}

// Post performs an HTTP POST for a given entity path and body
func (em *entityManager) Post(ctx context.Context, entityPath string, body []byte, mw ...MiddlewareFunc) (*http.Response, error) {
	ctx, span := em.startSpanFromContext(ctx, "sb.EntityManger.Post")
	defer span.End()

	return em.Execute(ctx, http.MethodPost, entityPath, bytes.NewReader(body), mw...)
}

func (em *entityManager) Execute(ctx context.Context, method string, entityPath string, body io.Reader, mw ...MiddlewareFunc) (*http.Response, error) {
	ctx, span := em.startSpanFromContext(ctx, "sb.EntityManger.Execute")
	defer span.End()

	req, err := http.NewRequest(method, em.Host+strings.TrimPrefix(entityPath, "/"), body)
	if err != nil {
		tab.For(ctx).Error(err)
		return nil, err
	}

	final := func(_ RestHandler) RestHandler {
		return func(reqCtx context.Context, request *http.Request) (*http.Response, error) {
			client := &http.Client{
				Timeout: 60 * time.Second,
			}
			request = request.WithContext(reqCtx)
			return client.Do(request)
		}
	}

	mwStack := []MiddlewareFunc{final}
	sl := len(em.mwStack) - 1
	for i := sl; i >= 0; i-- {
		mwStack = append(mwStack, em.mwStack[i])
	}

	for i := len(mw) - 1; i >= 0; i-- {
		mwStack = append(mwStack, mw[i])
	}

	var h RestHandler
	for _, mw := range mwStack {
		h = mw(h)
	}

	return h(ctx, req)
}

// Use adds middleware to the middleware mwStack
func (em *entityManager) Use(mw ...MiddlewareFunc) {
	em.mwStack = append(em.mwStack, mw...)
}

// TokenProvider generates authorization tokens for communicating with the Service Bus management API
func (em *entityManager) TokenProvider() auth.TokenProvider {
	return em.tokenProvider
}

func addAuthorization(tp auth.TokenProvider) MiddlewareFunc {
	return func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (*http.Response, error) {
			signature, err := tp.GetToken(req.URL.String())
			if err != nil {
				return nil, err
			}

			req.Header.Add("Authorization", signature.Token)
			return next(ctx, req)
		}
	}
}

func addSupplementalAuthorization(supplementalURI string, tp auth.TokenProvider) MiddlewareFunc {
	return func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (*http.Response, error) {
			signature, err := tp.GetToken(supplementalURI)
			if err != nil {
				return nil, err
			}

			req.Header.Add("ServiceBusSupplementaryAuthorization", signature.Token)
			return next(ctx, req)
		}
	}
}

func addDeadLetterSupplementalAuthorization(targetURI string, tp auth.TokenProvider) MiddlewareFunc {
	return func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (response *http.Response, e error) {
			signature, err := tp.GetToken(targetURI)
			if err != nil {
				return nil, err
			}

			req.Header.Add("ServiceBusDlqSupplementaryAuthorization", signature.Token)
			return next(ctx, req)
		}
	}
}

// TraceReqAndResponseMiddleware will print the dump of the management request and response.
//
// This should only be used for debugging or educational purposes.
func TraceReqAndResponseMiddleware() MiddlewareFunc {
	return func(next RestHandler) RestHandler {
		return func(ctx context.Context, req *http.Request) (*http.Response, error) {
			if dump, err := httputil.DumpRequest(req, true); err == nil {
				fmt.Println(string(dump))
			}

			res, err := next(ctx, req)

			if dump, err := httputil.DumpResponse(res, true); err == nil {
				fmt.Println(string(dump))
			}

			return res, err
		}
	}
}

func isEmptyFeed(b []byte) bool {
	var emptyFeed queueFeed
	feedErr := xml.Unmarshal(b, &emptyFeed)
	return feedErr == nil && emptyFeed.Title == "Publicly Listed Services"
}

func xmlDoc(content []byte) []byte {
	return []byte(xml.Header + string(content))
}

// ptrBool takes a boolean and returns a pointer to that bool. For use in literal pointers, ptrBool(true) -> *bool
func ptrBool(toPtr bool) *bool {
	return &toPtr
}

// ptrString takes a string and returns a pointer to that string. For use in literal pointers,
// ptrString(fmt.Sprintf("..", foo)) -> *string
func ptrString(toPtr string) *string {
	return &toPtr
}

// durationTo8601Seconds takes a duration and returns a string period of whole seconds (int cast of float)
func durationTo8601Seconds(duration time.Duration) string {
	return fmt.Sprintf("PT%dS", duration/time.Second)
}

func formatManagementError(body []byte) error {
	var mgmtError managementError
	unmarshalErr := xml.Unmarshal(body, &mgmtError)
	if unmarshalErr != nil {
		return errors.New(string(body))
	}

	return fmt.Errorf("error code: %d, Details: %s", mgmtError.Code, mgmtError.Detail)
}