Merge pull request #12 from subomi/subomi/feat/improve-migration-inte…

…rface

feat: improved core api

example/basic/go.mod

@@ -4,6 +4,7 @@ go 1.18
 
 require (
 	github.com/gorilla/mux v1.8.0
+	github.com/prometheus/client_golang v1.16.0
 	github.com/subomi/requestmigrations v0.1.0
 )
 
@@ -13,7 +14,6 @@ require (
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
-	github.com/prometheus/client_golang v1.16.0 // indirect
 	github.com/prometheus/client_model v0.3.0 // indirect
 	github.com/prometheus/common v0.42.0 // indirect
 	github.com/prometheus/procfs v0.10.1 // indirect

example/basic/go.sum

@@ -4,6 +4,7 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.3.5/go.mod h1:6O5/vntMXwX2lRkT1hjjk0nAC1IDOTvTlVgjlRvqsdk=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
@@ -15,6 +16,7 @@ github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=
 github.com/gorilla/mux v1.8.0/go.mod h1:DVbg23sWSpFRCP0SfiEN6jmj59UnW/n46BH5rLB71So=
 github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
 github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/prometheus/client_golang v1.16.0 h1:yk/hx9hDbrGHovbci4BY+pRMfSuuat626eFsHb7tmT8=
 github.com/prometheus/client_golang v1.16.0/go.mod h1:Zsulrv/L9oM40tJ7T815tM89lFEugiJ9HzIqaAx4LKc=
 github.com/prometheus/client_model v0.3.0 h1:UBgGFHqYdG/TPFD1B1ogZywDqEkwp3fBMvqdiQ7Xew4=
@@ -23,6 +25,7 @@ github.com/prometheus/common v0.42.0 h1:EKsfXEYo4JpWMHH5cg+KOUWeuJSov1Id8zGR8eeI
 github.com/prometheus/common v0.42.0/go.mod h1:xBwqVerjNdUDjgODMpudtOMwlOwf2SaTr1yjz4b7Zbc=
 github.com/prometheus/procfs v0.10.1 h1:kYK1Va/YMlutzCGazswoHKo//tZVlFpKYh+PymziUAg=
 github.com/prometheus/procfs v0.10.1/go.mod h1:nwNm2aOCAYw8uTR/9bWRREkZFxAUcWzPHWJq+XBB/FM=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -31,3 +34,4 @@ google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp0
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.30.0 h1:kPPoIgf3TsEvrm0PFe15JQ+570QVxYzEvvHqChK+cng=
 google.golang.org/protobuf v1.30.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

example/basic/main.go

@@ -83,7 +83,7 @@ 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
+	randNum := rand.Intn(2-1+1) + 1
 	time.Sleep(time.Duration(randNum) * time.Second)
 
 	users, err := a.store.GetAll()

example/basic/requestmigrations.go

@@ -1,39 +1,32 @@
 package main
 
 import (
-	"bytes"
 	"encoding/json"
-	"fmt"
-	"io"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 )
 
 // 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) ShouldMigrateConstraint(
+	url *url.URL,
+	method string,
+	data []byte,
+	isReq bool) bool {
 
-func (c *combineNamesForUserMigration) ShouldMigrateResponse(
-	req *http.Request,
-	res *http.Response) bool {
+	isUserPath := url.Path == "/users"
+	isGetMethod := method == http.MethodGet
+	isValidType := isReq == false
 
-	isUserPath := req.URL.Path == "/users"
-	isGetMethod := req.Method == http.MethodGet
-
-	return isUserPath && isGetMethod
+	return isUserPath && isGetMethod && isValidType
 }
 
-func (c *combineNamesForUserMigration) MigrateResponse(r *http.Response) error {
+func (c *combineNamesForUserMigration) Migrate(
+	body []byte,
+	h http.Header) ([]byte, http.Header, error) {
 	type oldUser struct {
 		UID       string    `json:"uid"`
 		Email     string    `json:"email"`
@@ -43,21 +36,16 @@ func (c *combineNamesForUserMigration) MigrateResponse(r *http.Response) error {
 		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)
+	err := json.Unmarshal(body, &res)
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
 	var users []*oldUser20230501
 	err = json.Unmarshal(res.Data, &users)
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
 	var newUsers []*oldUser
@@ -74,11 +62,10 @@ func (c *combineNamesForUserMigration) MigrateResponse(r *http.Response) error {
 
 	body, err = generateSuccessResponse(&newUsers, "users retrieved successfully")
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
-	r.Body = io.NopCloser(bytes.NewReader(body))
-	return nil
+	return body, h, nil
 }
 
 type oldUser20230501 struct {
@@ -93,40 +80,32 @@ type oldUser20230501 struct {
 
 type expandProfileForUserMigration struct{}
 
-func (e *expandProfileForUserMigration) ShouldMigrateRequest(r *http.Request) bool {
-	return false
-}
-
-func (e *expandProfileForUserMigration) MigrateRequest(r *http.Request) error {
-	return nil
-}
-
-func (e *expandProfileForUserMigration) ShouldMigrateResponse(
-	req *http.Request,
-	res *http.Response) bool {
+func (e *expandProfileForUserMigration) ShouldMigrateConstraint(
+	url *url.URL,
+	method string,
+	body []byte,
+	isReq bool) bool {
 
-	isUserPath := req.URL.Path == "/users"
-	isGetMethod := req.Method == http.MethodGet
+	isUserPath := url.Path == "/users"
+	isGetMethod := method == http.MethodGet
+	isValidType := isReq == false
 
-	return isUserPath && isGetMethod
+	return isUserPath && isGetMethod && isValidType
 }
 
-func (e *expandProfileForUserMigration) MigrateResponse(r *http.Response) error {
-	body, err := io.ReadAll(r.Body)
-	if err != nil {
-		return err
-	}
-
+func (e *expandProfileForUserMigration) Migrate(
+	body []byte,
+	h http.Header) ([]byte, http.Header, error) {
 	var res ServerResponse
-	err = json.Unmarshal(body, &res)
+	err := json.Unmarshal(body, &res)
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
 	var users []*User
 	err = json.Unmarshal(res.Data, &users)
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
 	var newUsers []*oldUser20230501
@@ -144,9 +123,8 @@ func (e *expandProfileForUserMigration) MigrateResponse(r *http.Response) error
 
 	body, err = generateSuccessResponse(&newUsers, "users retrieved successfully")
 	if err != nil {
-		return err
+		return nil, nil, err
 	}
 
-	r.Body = io.NopCloser(bytes.NewReader(body))
-	return nil
+	return body, h, nil
 }

requestmigrations.go

@@ -1,10 +1,12 @@
 package requestmigrations
 
 import (
+	"bytes"
 	"errors"
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"sort"
 	"sync"
 	"time"
@@ -38,11 +40,8 @@ type Migrations map[string][]Migration
 // needs to implement. It includes two predicate functions and two
 // transformation functions.
 type Migration interface {
-	ShouldMigrateRequest(req *http.Request) bool
-	MigrateRequest(req *http.Request) error
-
-	ShouldMigrateResponse(req *http.Request, res *http.Response) bool
-	MigrateResponse(res *http.Response) error
+	Migrate(data []byte, header http.Header) ([]byte, http.Header, error)
+	ShouldMigrateConstraint(url *url.URL, method string, data []byte, isReq bool) bool
 }
 
 type GetUserVersionFunc func(req *http.Request) (string, error)
@@ -271,6 +270,13 @@ func (m *migrator) applyRequestMigrations(req *http.Request) error {
 		return nil
 	}
 
+	data, err := io.ReadAll(req.Body)
+	if err != nil {
+		return err
+	}
+
+	header := req.Header.Clone()
+
 	for _, version := range m.versions {
 		migrations, ok := m.migrations[version.String()]
 		if !ok {
@@ -283,17 +289,22 @@ func (m *migrator) applyRequestMigrations(req *http.Request) error {
 		}
 
 		for _, migration := range migrations {
-			if !migration.ShouldMigrateRequest(req) {
+			if !migration.ShouldMigrateConstraint(req.URL, req.Method, data, true) {
 				continue
 			}
 
-			err := migration.MigrateRequest(req)
+			data, header, err = migration.Migrate(data, header)
 			if err != nil {
 				return err
 			}
 		}
 	}
 
+	req.Header = header
+
+	// set the body back for the rest of the middleware.
+	req.Body = io.NopCloser(bytes.NewReader(data))
+
 	return nil
 }
 
@@ -302,6 +313,13 @@ func (m *migrator) applyResponseMigrations(
 	rr *httptest.ResponseRecorder, w http.ResponseWriter) error {
 	res := rr.Result()
 
+	data, err := io.ReadAll(res.Body)
+	if err != nil {
+		return err
+	}
+
+	header := res.Header.Clone()
+
 	for i := len(m.versions); i > 0; i-- {
 		version := m.versions[i-1]
 		migrations, ok := m.migrations[version.String()]
@@ -315,18 +333,18 @@ func (m *migrator) applyResponseMigrations(
 		}
 
 		for _, migration := range migrations {
-			if !migration.ShouldMigrateResponse(req, res) {
+			if !migration.ShouldMigrateConstraint(req.URL, req.Method, data, false) {
 				continue
 			}
 
-			err := migration.MigrateResponse(res)
+			data, header, err = migration.Migrate(data, header)
 			if err != nil {
 				return ErrServerError
 			}
 		}
 	}
 
-	err := m.finalResponder(w, res)
+	err = m.finalResponder(w, data, header)
 	if err != nil {
 		// log error.
 		return ErrServerError
@@ -335,17 +353,12 @@ func (m *migrator) applyResponseMigrations(
 	return nil
 }
 
-func (m *migrator) finalResponder(w http.ResponseWriter, res *http.Response) error {
-	body, err := io.ReadAll(res.Body)
-	if err != nil {
-		return err
-	}
-
-	for k, v := range res.Header {
+func (m *migrator) finalResponder(w http.ResponseWriter, body []byte, h http.Header) error {
+	for k, v := range h {
 		w.Header()[k] = v
 	}
 
-	_, err = w.Write(body)
+	_, err := w.Write(body)
 	if err != nil {
 		return err
 	}