Merge pull request #10 from subomi/subomi/feat/improve-example

feat: improved examples and fixed migration bug

Author: subomi

example/basic/call_api.sh

@@ -2,25 +2,35 @@
 
 helpFunc() {
 	echo "Usage: $0 -r"
+	echo -e "\t-n Specify how many iterations we call the API."
 	echo -e "\t-r Specify request type, see options below:"
 	echo -e "\t   - lu: list users without versioning"
 	echo -e "\t   - lvu: list users with versioning"
 	exit 1
 }
 
-while getopts ":r:" opt; do
+n=1
+
+while getopts ":n:r:" opt; do
 	case "$opt" in
+		n)
+			n=$OPTARG
+			;;
 		r)
 			req="$OPTARG"
 
 			if [[ "$req" == "lu" ]]; then
-				curl -s localhost:9000/users \
-					-H "Content-Type: application/json"  | jq
+				for ((i=0; i<n; i++)); do
+					curl -s localhost:9000/users \
+						-H "Content-Type: application/json"  | jq
+				done
 
 			elif [[ "$req" == "lvu" ]]; then
-				curl -s localhost:9000/users \
-					-H "Content-Type: application/json" \
-					-H "X-Example-Version: 2023-09-02" | jq
+				for ((i=0; i<n; i++)); do
+					curl -s localhost:9000/users \
+						-H "Content-Type: application/json" \
+						-H "X-Example-Version: 2023-04-01" | jq
+				done
 
 			else
 				helpFunc

example/basic/main.go

@@ -3,9 +3,11 @@ package main
 import (
 	"encoding/json"
 	"log"
+	"math/rand"
 	"net/http"
 	"os"
 	"os/signal"
+	"time"
 
 	"github.com/gorilla/mux"
 	"github.com/prometheus/client_golang/prometheus"
@@ -14,16 +16,26 @@ import (
 )
 
 func main() {
-	rm := rms.NewRequestMigration(
+	// Set the seed value for the random number generator
+	rand.Seed(time.Now().UnixNano())
+
+	rm, err := rms.NewRequestMigration(
 		&rms.RequestMigrationOptions{
 			VersionHeader:  "X-Example-Version",
-			CurrentVersion: "2023-09-02",
+			CurrentVersion: "2023-05-01",
 			VersionFormat:  rms.DateFormat,
 		})
 
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	rm.RegisterMigrations(rms.Migrations{
-		"2023-09-02": []rms.Migration{
-			&CombineNamesForUserMigration{},
+		"2023-05-01": []rms.Migration{
+			&expandProfileForUserMigration{},
+		},
+		"2023-04-01": []rms.Migration{
+			&combineNamesForUserMigration{},
 		},
 	})
 
@@ -33,7 +45,7 @@ func main() {
 		Handler: buildMux(api),
 	}
 
-	err := backend.ListenAndServe()
+	err = backend.ListenAndServe()
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -45,9 +57,9 @@ func main() {
 
 func buildMux(api *API) http.Handler {
 	m := mux.NewRouter()
-	m.Use(api.rm.VersionAPI)
 
-	m.HandleFunc("/users", api.ListUser).Methods("GET")
+	m.Handle("/users",
+		api.rm.VersionAPI(http.HandlerFunc(api.ListUser))).Methods("GET")
 	m.HandleFunc("/users/{id}", api.GetUser).Methods("GET")
 
 	reg := prometheus.NewRegistry()
@@ -73,6 +85,10 @@ type API struct {
 }
 
 func (a *API) ListUser(w http.ResponseWriter, r *http.Request) {
+	// Generate a random Int type number between 1 and 10
+	randNum := rand.Intn(3-1+1) + 1
+	time.Sleep(time.Duration(randNum) * time.Second)
+
 	users, err := a.store.GetAll()
 	if err != nil {
 		w.WriteHeader(http.StatusBadGateway)

example/basic/requestmigrations.go

@@ -10,28 +10,98 @@ import (
 	"time"
 )
 
-type OldUser struct {
+// Migrations
+type combineNamesForUserMigration struct{}
+
+func (c *combineNamesForUserMigration) ShouldMigrateRequest(r *http.Request) bool {
+	return false
+}
+
+func (c *combineNamesForUserMigration) MigrateRequest(r *http.Request) error {
+	fmt.Println("migrating request...")
+
+	return nil
+}
+
+func (c *combineNamesForUserMigration) ShouldMigrateResponse(
+	req *http.Request,
+	res *http.Response) bool {
+
+	isUserPath := req.URL.Path == "/users"
+	isGetMethod := req.Method == http.MethodGet
+
+	return isUserPath && isGetMethod
+}
+
+func (c *combineNamesForUserMigration) MigrateResponse(r *http.Response) error {
+	type oldUser struct {
+		UID       string    `json:"uid"`
+		Email     string    `json:"email"`
+		FullName  string    `json:"full_name"`
+		Profile   string    `json:"profile"`
+		CreatedAt time.Time `json:"created_at"`
+		UpdatedAt time.Time `json:"updated_at"`
+	}
+
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		return err
+	}
+
+	var res ServerResponse
+	err = json.Unmarshal(body, &res)
+	if err != nil {
+		return err
+	}
+
+	var users []*oldUser20230501
+	err = json.Unmarshal(res.Data, &users)
+	if err != nil {
+		return err
+	}
+
+	var newUsers []*oldUser
+	for _, u := range users {
+		var oldUser oldUser
+		oldUser.UID = u.UID
+		oldUser.Email = u.Email
+		oldUser.FullName = strings.Join([]string{u.FirstName, u.LastName}, " ")
+		oldUser.Profile = u.Profile
+		oldUser.CreatedAt = u.CreatedAt
+		oldUser.UpdatedAt = u.UpdatedAt
+		newUsers = append(newUsers, &oldUser)
+	}
+
+	body, err = generateSuccessResponse(&newUsers, "users retrieved successfully")
+	if err != nil {
+		return err
+	}
+
+	r.Body = io.NopCloser(bytes.NewReader(body))
+	return nil
+}
+
+type oldUser20230501 struct {
 	UID       string    `json:"uid"`
 	Email     string    `json:"email"`
-	Name      string    `json:"name"`
+	FirstName string    `json:"first_name"`
+	LastName  string    `json:"last_name"`
+	Profile   string    `json:"profile"`
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 }
 
-// Migrations
-type CombineNamesForUserMigration struct{}
+type expandProfileForUserMigration struct{}
 
-func (c *CombineNamesForUserMigration) ShouldMigrateRequest(r *http.Request) bool {
-	return true
+func (e *expandProfileForUserMigration) ShouldMigrateRequest(r *http.Request) bool {
+	return false
 }
 
-func (c *CombineNamesForUserMigration) MigrateRequest(r *http.Request) error {
-	fmt.Println("migrating request...")
-
+func (e *expandProfileForUserMigration) MigrateRequest(r *http.Request) error {
 	return nil
 }
 
-func (c *CombineNamesForUserMigration) ShouldMigrateResponse(
+func (e *expandProfileForUserMigration) ShouldMigrateResponse(
 	req *http.Request,
 	res *http.Response) bool {
 
@@ -41,7 +111,7 @@ func (c *CombineNamesForUserMigration) ShouldMigrateResponse(
 	return isUserPath && isGetMethod
 }
 
-func (c *CombineNamesForUserMigration) MigrateResponse(r *http.Response) error {
+func (e *expandProfileForUserMigration) MigrateResponse(r *http.Response) error {
 	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		return err
@@ -59,18 +129,20 @@ func (c *CombineNamesForUserMigration) MigrateResponse(r *http.Response) error {
 		return err
 	}
 
-	var newUsers []*OldUser
+	var newUsers []*oldUser20230501
 	for _, u := range users {
-		var oldUser OldUser
+		var oldUser oldUser20230501
 		oldUser.UID = u.UID
 		oldUser.Email = u.Email
-		oldUser.Name = strings.Join([]string{u.FirstName, u.LastName}, " ")
+		oldUser.FirstName = u.FirstName
+		oldUser.LastName = u.LastName
+		oldUser.Profile = u.Profile.UID
 		oldUser.CreatedAt = u.CreatedAt
 		oldUser.UpdatedAt = u.UpdatedAt
 		newUsers = append(newUsers, &oldUser)
 	}
 
-	body, err = json.Marshal(&newUsers)
+	body, err = generateSuccessResponse(&newUsers, "users retrieved successfully")
 	if err != nil {
 		return err
 	}

example/basic/store.go

@@ -16,6 +16,11 @@ func init() {
 				Email:     "[email protected]",
 				FirstName: "Subomi",
 				LastName:  "Oluwalana",
+				Profile: &profile{
+					UID:        "999",
+					GithubURL:  "https://github.com/subomi",
+					TwitterURL: "https://twitter.com/subomiOluwalana",
+				},
 				CreatedAt: time.Date(2023, time.March, 10, 7, 0, 0, 0, time.UTC),
 				UpdatedAt: time.Date(2023, time.March, 10, 7, 0, 0, 0, time.UTC),
 			},
@@ -24,6 +29,11 @@ func init() {
 				Email:     "[email protected]",
 				FirstName: "Raymond",
 				LastName:  "Tukpe",
+				Profile: &profile{
+					UID:        "888",
+					GithubURL:  "https://github.com/jirevwe",
+					TwitterURL: "https://twitter.com/rtukpe",
+				},
 				CreatedAt: time.Date(2023, time.March, 10, 7, 0, 0, 0, time.UTC),
 				UpdatedAt: time.Date(2023, time.March, 10, 7, 0, 0, 0, time.UTC),
 			},
@@ -32,6 +42,11 @@ func init() {
 				Email:     "[email protected]",
 				FirstName: "Daniel",
 				LastName:  "Oluojomu",
+				Profile: &profile{
+					UID:        "777",
+					GithubURL:  "https://github.com/danvixent",
+					TwitterURL: "https://twitter.com/danvixent",
+				},
 				CreatedAt: time.Date(2023, time.March, 10, 7, 0, 0, 0, time.UTC),
 				UpdatedAt: time.Date(2023, time.March, 10, 7, 0, 0, 0, time.UTC),
 			},
@@ -45,10 +60,17 @@ type User struct {
 	Email     string    `json:"email"`
 	FirstName string    `json:"first_name"`
 	LastName  string    `json:"last_name"`
+	Profile   *profile  `json:"profile"`
 	CreatedAt time.Time `json:"created_at"`
 	UpdatedAt time.Time `json:"updated_at"`
 }
 
+type profile struct {
+	UID        string `json:"uid"`
+	GithubURL  string `json:"github_url"`
+	TwitterURL string `json:"twitter_url"`
+}
+
 type Store struct {
 	mu    sync.Mutex
 	users []*User

requestmigrations.go

@@ -2,6 +2,7 @@ package requestmigrations
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"net/http/httptest"
@@ -25,14 +26,16 @@ var (
 	ErrInvalidVersionFormat = errors.New("Invalid version format")
 )
 
-//	migrations := Migrations{
-//		"2023-02-28": []Migration{
-//			Migration{},
-//			Migration{},
-//		},
-//	}
+// migrations := Migrations{
+//   "2023-02-28": []Migration{
+//     Migration{},
+//	   Migration{},
+//	 },
+// }
 type Migrations map[string][]Migration
 
+// Migration is the core interface each transformation in every version
+// needs to implement.
 type Migration interface {
 	ShouldMigrateRequest(req *http.Request) bool
 	MigrateRequest(req *http.Request) error
@@ -129,6 +132,7 @@ func (rm *RequestMigration) VersionAPI(next http.Handler) http.Handler {
 			return
 		}
 
+		fmt.Printf("from: %v, to: %v\n", from, to)
 		if from.Equal(to) {
 			next.ServeHTTP(w, req)
 			return
@@ -240,6 +244,11 @@ func (m *Migrator) applyRequestMigrations(req *http.Request) error {
 			return ErrInvalidVersion
 		}
 
+		// skip initial version.
+		if m.from.Equal(version) {
+			continue
+		}
+
 		for _, migration := range migrations {
 			if !migration.ShouldMigrateRequest(req) {
 				continue
@@ -261,12 +270,17 @@ func (m *Migrator) applyResponseMigrations(
 	res := rr.Result()
 
 	for i := len(m.versions); i > 0; i-- {
-		v := m.versions[i-1].String()
-		migrations, ok := m.migrations[v]
+		version := m.versions[i-1]
+		migrations, ok := m.migrations[version.String()]
 		if !ok {
 			return ErrServerError
 		}
 
+		// skip initial version.
+		if m.from.Equal(version) {
+			continue
+		}
+
 		for _, migration := range migrations {
 			if !migration.ShouldMigrateResponse(req, res) {
 				continue