I have the requirement to test a Kafka consumer method which in turn creates a post call to another service. How can I write wiremock for the another service. The code is:
Kafka Consumer
func (handler FxmWorklogEventHandler) ProcessMessage(message kafka.Message) (swgykafka.Status, error) {
txn := util.TraceTransaction(handler.MessageType())
if txn != nil {
defer txn.End()
}
var fxmWorklogEvent event.FxmWorklogEvent
err := json.Unmarshal(message.Data, &fxmWorklogEvent)
if err != nil {
log.Error().Err(err).Msg("FxmWorklogEventHandler - Failed to un marshall the message")
return swgykafka.HardFailure, err
}
log.Info().Msgf("Processing fxm worklog event for order %s", fxmWorklogEvent.OrderId)
fxmEventToPersist := BuildFxmEventToPersist(fxmWorklogEvent)
_, err = handler.am.SaveFxmWorklog(fxmEventToPersist)
if err != nil {
log.Error().Err(err).Msgf("Failed to save fxm worklog event in am for order %s", fxmWorklogEvent.OrderId)
return swgykafka.SoftFailure, nil
}
return swgykafka.Success, nil
}
Post Call
func (am *AssistanceManagerClient) SaveFxmWorklog(r request.FxmWorklogDetails) (*response.BaseResponse, error) {
url := config.Client.GetString(amHost) + util.AssistanceManagerSaveFxmWorklog
return am.hc.Post(url, r, http.Header{}, util.AssistanceManagerCommand)
}
External Service Method
func SaveFxmWorklog(w http.ResponseWriter, r *http.Request) {
var rb entity.FxmWorklogDetails
err := json.NewDecoder(r.Body).Decode(&rb)
if err != nil {
log.Error().Err(err).Msgf("Failed to parse the fxm worklog request %s", util.ToJSON(rb))
util.ErrorResponse(w, err.Error(), http.StatusBadRequest)
return
}
log.Info().Msgf("Save fxm worklog request received for order %s", rb.OrderId)
response, err := service.FxmService.SaveFxmWorklogEvent(rb)
if err != nil {
log.Error().Err(err).Msgf("Failed to save fxm worklog event %s", util.ToJSON(rb))
util.ErrorResponse(w, err.Error(), http.StatusInternalServerError)
return
}
w.WriteHeader(response.HTTPStatusCode)
_ = json.NewEncoder(w).Encode(response)
}
How can I test this method by wiremocking the external service api call?
Related
I have a function designed to listen to a Nats subject and route the messages as it receives them:
func (conn *JetStreamConnection) SubscribeMultiple(ctx context.Context, subject string,
subscribers ...*SubscriptionCallback) error {
callbacks := make(map[string]func(*pnats.NatsMessage) (func(context.Context), error))
for _, subscriber := range subscribers {
callbacks[subscriber.Category] = subscriber.Callback
}
fullSubject := fmt.Sprintf("%s.*", subject)
sub, err := conn.context.SubscribeSync(fullSubject, nats.Context(ctx))
if err != nil {
return err
}
loop:
for {
select {
case <-ctx.Done():
break loop
default:
}
msg, err := sub.NextMsgWithContext(ctx)
if err != nil {
return err
}
msg.InProgress()
var message pnats.NatsMessage
if err := conn.unmarshaller(msg.Data, &message); err != nil {
msg.Term()
return err
}
actualSubject := fmt.Sprintf("%s.%s", subject, message.Context.Category)
subscriber, ok := callbacks[message.Context.Category]
if !ok {
msg.Nak()
continue
}
callback, err := subscriber(&message)
if err == nil {
msg.Ack()
} else {
msg.Nak()
return err
}
callback(ctx)
}
if err := sub.Unsubscribe(); err != nil {
return err
}
return nil
}
My problem is that, since the SubscribeSync function produces a *nats.Subscription object, I have no way to mock out the test. How can I test around this object?
You can put your loop in a separate function. This func can accept an interface that describes nats Subscription instead of *nats.Subscription. This way you will be able to create Subscription mocks with gomock or other tools. After that you can test the inside func separately
Something like this:
func (conn *JetStreamConnection) SubscribeMultiple(ctx context.Context, subject string,
subscribers ...*SubscriptionCallback) error {
callbacks := make(map[string]func(*pnats.NatsMessage) (func(context.Context), error))
for _, subscriber := range subscribers {
callbacks[subscriber.Category] = subscriber.Callback
}
fullSubject := fmt.Sprintf("%s.*", subject)
sub, err := conn.context.SubscribeSync(fullSubject, nats.Context(ctx))
if err != nil {
return err
}
return run(ctx, sub)
}
//go:generate mockgen -source conn.go -destination ../mocks/conn.go -package mocks
type ISubscription interface{
NextMsgWithContext(ctx context.Context) (*nats.Msg, error)
Unsubscribe() error
}
func (conn *JetStreamConnection) run(ctx context.Context, sub ISubscription) error {
loop:
for {
select {
case <-ctx.Done():
break loop
default:
}
msg, err := sub.NextMsgWithContext(ctx)
if err != nil {
return err
}
msg.InProgress()
var message pnats.NatsMessage
if err := conn.unmarshaller(msg.Data, &message); err != nil {
msg.Term()
return err
}
actualSubject := fmt.Sprintf("%s.%s", subject, message.Context.Category)
subscriber, ok := callbacks[message.Context.Category]
if !ok {
msg.Nak()
continue
}
callback, err := subscriber(&message)
if err == nil {
msg.Ack()
} else {
msg.Nak()
return err
}
callback(ctx)
}
if err := sub.Unsubscribe(); err != nil {
return err
}
}
upd: if you still want to test SubscribeMultiple, you can create a Runner that will have only one func Run and take it as dependency for JetStreamConnection. Again, you can create a mock for Runner and test with it
I'm trying to implement pgxpool in a new go app. I keep getting a "pool closed" error after attempting a scan into a struct.
The pgx logger into gives me this after connecting. I thought the pgxpool was meant to remain open.
{"level":"info","msg":"closed connection","pid":5499,"time":"2022-02-24T16:36:33+10:30"}
Here is my router code
func router() http.Handler {
var err error
config, err := pgxpool.ParseConfig(os.Getenv("DATABASE_URL"))
if err != nil {
log.Fatalln(err)
}
log.Println(os.Getenv("DATABASE_URL"))
logrusLogger := &logrus.Logger{
Out: os.Stderr,
Formatter: new(logrus.JSONFormatter),
Hooks: make(logrus.LevelHooks),
Level: logrus.InfoLevel,
ExitFunc: os.Exit,
ReportCaller: false,
}
config.ConnConfig.Logger = NewLogger(logrusLogger)
db, err := pgxpool.ConnectConfig(context.Background(), config)
if err != nil {
log.Fatalln(err)
}
defer db.Close()
--- minio connection
rs := newAppResource(db, mc)
Then, in a helper file I setup the resource
type appResource struct {
db *pgxpool.Pool
mc *minio.Client
}
// newAppResource function to pass global var
func newAppResource(db *pgxpool.Pool, mc *minio.Client) *appResource {
return &appResource{
db: db,
mc: mc,
}
}
There "pool closed" error occurs at the end of this code
func (rs *appResource) login(w http.ResponseWriter, r *http.Request) {
var user User
var login Login
d := json.NewDecoder(r.Body)
d.DisallowUnknownFields() // catch unwanted fields
err := d.Decode(&login)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
if err != nil {
fmt.Println("can't decode JSON", err)
}
if login.Email == "" {
log.Println("empty email")
return
}
log.Println(login.Email)
log.Println(login.Password)
if login.Password == "" {
log.Println("empty password")
return
}
// optional extra check
if d.More() {
http.Error(w, "extraneous data after JSON object", http.StatusBadRequest)
return
}
sqlStatement := "SELECT user_id, password FROM users WHERE active = 'true' AND email = ?"
row := rs.db.QueryRow(context.Background(), sqlStatement, login.Email)
err = row.Scan(&user.UserId, &user.Password)
if err == sql.ErrNoRows {
log.Println("user not found")
http.Error(w, err.Error(), http.StatusUnauthorized)
return
}
if err != nil {
log.Println(err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
It appears that you are doing something like the following:
func router() http.Handler {
db, err := pgxpool.ConnectConfig(context.Background(), config)
if err != nil {
log.Fatalln(err)
}
defer db.Close()
return appResource{db: db}
}
The issue with this is that the defer db.Close() runs when the function router() ends and this is before the returned pgxPool.Pool is actually used (the http.Handler returned will be used later when http requests are processed). Attempting to use a closed pgxPool.Pool results in the error you are seeing.
The simplest solution is to simply remove the defer db.Close() however you might also consider calling db.Close() as part of a clean shutdown process (it needs to remain open as long as you are handling requests).
You are using pgxpool which does differ from the standard library; however I believe that the advice given in the standard library docs applies here:
It is rarely necessary to close a DB.
I have use case where a Go Client with a file-watcher listens to changes in a file and sends these changes to a Go server. If the Client can't reach the server during the POST requests with the payload of the file changes, the Client will keep trying every 3 seconds to send the request until err := http.NewRequest() dosen't return a non-nil err
But If the Client is currently trying every 3 seconds to send a POST request but at the same time a new change occurs to the file under file-watch, I want the current POST requests's payload to be overwritten by the new payload(new changes from the file)
How Do I archive this best?
Client code for sending an HTTP requests
func makeRequest(method string, body io.Reader) (*http.Response, error) {
client := &http.Client{}
request, err := http.NewRequest(.., .., ..)
if err != nil {
log.Println("Error: Couldn't make a new Request:", err)
return nil, err
}
response, err := client.Do(request)
if err != nil {
log.Printf("Error: Couldn't execute %s request:%s", method, err)
}
return response, err
}
The function that retries until err !=nil
func autoRetry(f func() error) {
if err := backoff.Retry(f, getBackOff()); err != nil {
log.Println("Error: Couldn't execute exponential backOff retries: ", err)
}
}
autoRetry() is just a function which takes a function and uses ExponentialBackOff to calculate the amount of tries until err !=nil
The call to the method doing the POST request with retries
func postTodo() {
autoRetry(func() error {
r, err := makeRequest("POST", getFileData())
if err != nil {
return err
}
if r.StatusCode != 200 {
return errors.New("Error:" + r.Status)
}
return nil
})
}
I have built a Backend API in Go, it works however I want refactor the code for the DB access layer into a function - idiomatically.
// Get the form data entered by client; FirstName, LastName, phone Number,
// assign the person a unique i.d
// check to see if that user isn't in the database already
// if they are send an error message with the a 'bad' response code
// if they aren't in db add to db and send a message with success
func CreateStudentAccountEndpoint(response http.ResponseWriter, request *http.Request){
client, err := mongo.NewClient("mongodb://localhost:27017")
if err != nil {
log.Fatalf("Error connecting to mongoDB client Host: Err-> %v\n ", err)
}
ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()
err = client.Connect(ctx)
if err != nil {
log.Fatalf("Error Connecting to MongoDB at context.WtihTimeout: Err-> %v\n ", err)
}
response.Header().Set("Content-Type", "application/json")
studentCollection := client.Database(dbName).Collection("students")
_, err = studentCollection.InsertOne(context.Background(),data)
if err != nil {
response.WriteHeader(501)
response.Write([]byte(`{ "message": "` + err.Error() + `" }`))
}
// encoding json object for returning to the client
jsonStudent, err := json.Marshal(student)
if err != nil {
http.Error(response, err.Error(), http.StatusInternalServerError)
}
response.Write(jsonStudent)
}
I understand that I can create a method which returns (*mongoClient, err) as I utilise the client local variable later on in the code.
However I am lost as to how to implement the defer cancel() part because it executes once the method CreateStudenAccountEndpoint is at the end. But I am at a loss on how to implement this defer section in a method that will recognise that I want the defer to happen at the end of the function that calls the DB access layer method e.g CreateStudentAccountEndpoint not the actual db access method itself.
As I understand it, the connection should be long-lived and set up as a part of a constructor, i.e. not part of the request flow.
This will typically look something like this:
type BackendAPI struct {
client *mongo.Client
}
func NewBackendAPI(mongoURI string) (*BackendAPI, error) {
client, err := mongo.NewClient(mongoURI)
if err != nil {
return nil, err
}
ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()
err = client.Connect(ctx)
if err != nil {
return nil, err
}
return &BackendAPI{client}, nil
}
func (api *BackendAPI) func CreateStudentAccountEndpoint(response http.ResponseWriter, request *http.Request) {
response.Header().Set("Content-Type", "application/json")
// note the use of the long-lived api.client, which is connected already.
studentCollection := api.client.Database(dbName).Collection("students")
_, err = studentCollection.InsertOne(context.Background() ,data)
if err != nil {
response.WriteHeader(501)
response.Write([]byte(`{ "message": "` + err.Error() + `" }`))
return // at this point, the method should return
}
// encoding json object for returning to the client
jsonStudent, err := json.Marshal(student)
if err != nil {
http.Error(response, err.Error(), http.StatusInternalServerError)
}
response.Write(jsonStudent)
}
If you worry about losing the connection, you could implement a call to api.client.Ping in there, but in my opinion this should only be attempted if you encounter a failure you believe you can recover from by reconnecting.
I am new to Go and building web apps. An example of my handler is something like this:
func getAllPostsHandler(w http.ResponseWriter, r *http.Request) {
var posts []Post
dbSesstion := context.Get(r, "database").(*mgo.Session)
err := dbSesstion.DB(dbsett.Name).C(dbsett.Collection).Find(nil).All(&posts)
if err != nil {
log.Print("error: ", nil)
w.WriteHeader(http.StatusInternalServerError)
return
}
err = json.NewEncoder(w).Encode(posts)
if err != nil {
log.Print("error: ", nil)
w.WriteHeader(http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusOK)
}
My handlers have a lot of repeating error checking like this:
if err != nil {
log.Print("error: ", nil)
w.WriteHeader(http.StatusInternalServerError)
return
}
I want to make a function, which checks for error, print logs, write the response writer if neccessary, and return, but not only to the handler, but to stop all other response writings and return the handler itself. Is it possible to do so? I am thinking about panicing, but something tells me that its not the right way.
You can't escape outermost function from innermost but you can at least compact code a bit by inverting control flow
err := dbSesstion.DB(dbsett.Name).C(dbsett.Collection).Find(nil).All(&posts)
if err == nil {
err = json.NewEncoder(w).Encode(posts)
if err == nil {
err = somethingelse()
if err == nil {
w.WriteHeader(http.StatusOK)
return //successfully
}
}
}
log.Print("error: ", nil)
w.WriteHeader(http.StatusInternalServerError)