<div class="post-text" itemprop="text"> <p>I'm using mongo-go-driver, parallel connect several ports to check whether the port is listened by mongodb </p> <p>go version 1.12.3 mongo-go-driver v1.0</p> <pre class="lang-golang prettyprint-override"><code>type BaseServerStatus struct { Host string `bson:"host"` Version string `bson:"version"` Process string `bson:"process"` Pid int64 `bson:"pid"` Uptime int64 `bson:"uptime"` UptimeMillis int64 `bson:"uptimeMillis"` UptimeEstimate int64 `bson:"uptimeEstimate"` LocalTime time.Time `bson:"localTime"` } func GetBaseServerStatus(ip, port string) (srvStatus *BaseServerStatus, err error) { opts := options.Client() opts.SetDirect(true) opts.SetServerSelectionTimeout(1 * time.Second) opts.SetConnectTimeout(2 * time.Second) opts.SetSocketTimeout(2 * time.Second) opts.SetMaxConnIdleTime(1 * time.Second) opts.SetMaxPoolSize(1) url := fmt.Sprintf("mongodb://%s:%s/admin", ip, port) opts.ApplyURI(url) ctx, _ := context.WithTimeout(context.Background(), 2*time.Second) conn, err := mongo.Connect(ctx, opts) if err != nil { fmt.Printf("new %s:%s mongo connection error: %v ", ip, port, err) return } defer conn.Disconnect(ctx) err = conn.Ping(ctx, nil) if err != nil { fmt.Printf("ping %s:%s ping error: %v ", ip, port, err) return } sr := conn.Database("admin").RunCommand(ctx, bson.D{{"serverStatus", 1}}) if sr.Err() != nil { fmt.Printf("get %s:%s server status error: %v ", ip, port, sr.Err()) return } srvStatus = new(BaseServerStatus) err = sr.Decode(srvStatus) return } func main() { var wg sync.WaitGroup //ips := []string{"xxx.xxx.xxx.xxx:22"} ips := []string{"xxx.xxx.xxx.xxx:22", "xxx.xxx.xxx.xxx:80", "xxx.xxx.xxx.xxx:7005", "xxx.xxx.xxx.xxx:7017", "xxx.xxx.xxx.xxx:7006", "xxx.xxx.xxx.xxx:7016", "xxx.xxx.xxx.xxx:7018", "xxx.xxx.xxx.xxx:7014", "xxx.xxx.xxx.xxx:199", "xxx.xxx.xxx.xxx:8182", "xxx.xxx.xxx.xxx:7015", "xxx.xxx.xxx.xxx:7022", "xxx.xxx.xxx.xxx:7013", "xxx.xxx.xxx.xxx:7020", "xxx.xxx.xxx.xxx:9009", "xxx.xxx.xxx.xxx:7004", "xxx.xxx.xxx.xxx:7008", "xxx.xxx.xxx.xxx:7002", "xxx.xxx.xxx.xxx:7021", "xxx.xxx.xxx.xxx:7007", "xxx.xxx.xxx.xxx:7024", "xxx.xxx.xxx.xxx:7010", "xxx.xxx.xxx.xxx:7011", "xxx.xxx.xxx.xxx:7003", "xxx.xxx.xxx.xxx:7012", "xxx.xxx.xxx.xxx:7009", "xxx.xxx.xxx.xxx:7019", "xxx.xxx.xxx.xxx:8001", "xxx.xxx.xxx.xxx:7023", "xxx.xxx.xxx.xxx:111", "xxx.xxx.xxx.xxx:7001", "xxx.xxx.xxx.xxx:8002", "xxx.xxx.xxx.xxx:19313", "xxx.xxx.xxx.xxx:15772", "xxx.xxx.xxx.xxx:19777", "xxx.xxx.xxx.xxx:15778", "xxx.xxx.xxx.xxx:15776"} for _, ip := range ips { wg.Add(1) //time.Sleep(3 * time.Second) go func(addr string) { fmt.Printf("start to probe port %s ", addr) GetBaseServerStatus(strings.Split(addr, ":")[0], strings.Split(addr, ":")[1]) wg.Done() }(ip) } wg.Wait() fmt.Println("scan end") time.Sleep(20 * time.Second) } </code></pre> <p>however, run this code ,it consume 26GB memory I use pprof to diagnose, see below</p> <p>Showing top 10 nodes out of 15 flat flat% sum% cum cum% 26.29GB 96.86% 96.86% 26.29GB 96.86% go.mongodb.org/mongo-driver/x/network/connection.(*connection).ReadWireMessage</p> </div>

<div class="post-text" itemprop="text"> <p>I read in the following article that it is more efficient to use the natural ordering of <code>_id</code> to perform paging because skip always starts from the beginning from the collection</p> <p><a href="https://www.codementor.io/arpitbhayani/fast-and-efficient-pagination-in-mongodb-9095flbqr" rel="nofollow noreferrer">https://www.codementor.io/arpitbhayani/fast-and-efficient-pagination-in-mongodb-9095flbqr</a> </p> <pre><code>// Page 1 db.students.find().limit(10) // Page 2 last_id = ... # logic to get last_id db.students.find({'_id': {'$gt': last_id}}).limit(10) </code></pre> <p>But I have no idea how to perform the above using the <code>mongodb/mongo-go-driver</code>.</p> </div>

<div class="post-text" itemprop="text"> <p>Long, long ago, when we were using mgo.v2, we created some wrapper functions that copied the session, set the read pref and returned that for consumption by other libraries, e.g.</p> <pre class="lang-golang prettyprint-override"><code>func NewMonotonicConnection() (conn *Connection, success bool) { conn := &amp;Connection{ session: baseSession.Copy(), } conn.session.SetMode(mongo.Monotonic, true) return conn, true } </code></pre> <p>We now just pass the default client (initialized using mongo.Connect and passed into a connection singleton) in an init function and then consumed like this:</p> <pre class="lang-golang prettyprint-override"><code>func NewMonotonicConnection() (conn *Connection, success bool) { conn = defaultConnection return conn, true } </code></pre> <p>My understanding is that to leverage connection pooling, you need to use the same client (which is contained in defaultConn), and session is now implicitly handled inside of the <code>.All()</code>/cursor teardown. Please correct me if I'm wrong here.</p> <p>It would be nice if we could still set the readpref on these connections (e.g. set NearestMode on this connection before returning), but what's the community/standard way of doing that?</p> <ul> <li>I know I could call mongo.Connect over and over again, but is that expensive?</li> <li>I could create different clients - each client with a different readpref - but I was thinking that if a write occurred on that connection, it wouldn't ever go back to reading from a slave.</li> <li>It looks like I *can create sessions explicitly, but I'm not certain I should or if there are any implications around managing those explicitly in the new driver.</li> </ul> </div>

<div class="post-text" itemprop="text"> <p>The update function of mongo-go-driver can be called like this.</p> <pre class="lang-golang prettyprint-override"><code>filter := bson.D{"username", username} update := bson.D{{"$set", bson.D{ {"name", person.Name}, }, }} result, err := collection.UpdateOne(ctx, filter, update) </code></pre> <pre class="lang-golang prettyprint-override"><code>type Person struct { ID primitive.ObjectID `json:"_id,omitempty" bson:"_id,omitempty"` Username string `json:"username,omitempty" bson:"username,omitempty"` Name string `json:"name,omitempty" bson:"name,omitempty"` } </code></pre> <p>But, I need to call the update function using the <code>person</code> struct, without mentioning every field of person struct like this.</p> <pre class="lang-golang prettyprint-override"><code>filter := bson.D{"username", username} update := bson.D{{"$set", &lt;&lt;how to convert person struct to bson document?&gt;&gt;}} result, err := collection.UpdateOne(ctx, filter, update) </code></pre> <p>How can I convert the person struct to bson document?</p> </div>

<div class="post-text" itemprop="text"> <p>I'm trying to do a full text search on a collection, but in order to do that I need to create a text index. How can I create a text index on two fields?</p> <p>I know that I must use a thing as this:</p> <pre><code>opts := options.CreateIndexes().SetMaxTime(10 * time.Second) idxFiles := []mongo.IndexModel{ { Keys: bsonx.Doc{{"name": "text"}}, }, } db.Collection("mycollection").Indexes().CreateMany(context, idx, opts) </code></pre> </div>

<div class="post-text" itemprop="text"> <p>I'm trying to find a document by its auto generated _id field. Code below returns nothing:</p> <pre><code>var documentID bson.RawValue documentID.Type = 7 documentID.Value = []byte("5c7452c7aeb4c97e0cdb75bf") objID := documentID.ObjectID() value := collection.FindOne(ctx, bson.M{"_id": objID}) </code></pre> <p>The value I provided is a real document id I got from Mongo Express </p> <pre><code>"_id": ObjectID("5c7452c7aeb4c97e0cdb75bf") </code></pre> <p>In case you're wondering why I bother with RawValue, I found examples using bson.EC.ObjectID but bson package doesn't seem to have EC type, also I found some examples mentioning github.com/mongodb/mongo-go-driver/bson/objectid package, but I could not find that package either. I previously developed with mgo but I'm new to mongo-go-driver, so if you can point an easy way to declare an ObjectID. </p> </div>

<div class="post-text" itemprop="text"> <p>So I am trying to use <a href="https://github.com/mongodb/mongo-go-driver" rel="nofollow noreferrer">https://github.com/mongodb/mongo-go-driver</a> to connect to a mongo database in golang.</p> <p>Here is my connection handler: </p> <pre><code>var DB *mongo.Database func CreateConnectionHandler()(*mongo.Database, error){ fmt.Println("inside createConnection in database package") godotenv.Load() fmt.Println("in CreateConnectionHandler and SERVER_CONFIG: ") fmt.Println(os.Getenv("SERVER_CONFIG")) uri:="" if os.Getenv("SERVER_CONFIG")=="kubernetes"{ fmt.Println("inside kubernetes db config") uri = "mongodb://patientplatypus:SUPERSECRETPASSDOOT@ mongo-release-mongodb.default.svc.cluster.local:27017/ platypusNEST?authMechanism=SCRAM-SHA-1" }else if os.Getenv("SERVER_CONFIG")=="compose"{ fmt.Println("inside compose db config") uri = "mongodb://datastore:27017" } ctx, _ := context.WithTimeout(context.Background(), 10*time.Second) client, err := mongo.Connect(ctx, uri) if err != nil { return nil, fmt.Errorf("mongo client couldn't connect: %v", err) } DB := client.Database("platypusNEST") return DB, nil } </code></pre> <p>And the error I am getting: </p> <pre><code>api | database/connection.go:29:30: cannot use uri (type string) as type *options.ClientOptions in argument to mongo.Connect </code></pre> <p>So I tried replacing <code>uri</code> with the connection string like this: </p> <pre><code>client, err := mongo.Connect(ctx, "mongodb://datastore:27017") </code></pre> <p>But I still got the error.</p> <p>Compare this with what is in the documentation: </p> <blockquote> <pre><code>ctx, _ := context.WithTimeout(context.Background(), 10*time.Second) client, err := mongo.Connect(ctx, "mongodb://localhost:27017") </code></pre> </blockquote> <p>And it is exactly the same! I'm really not sure why there is this error. Any ideas?</p> </div>

<div class="post-text" itemprop="text"> <p>I have a little problem with my Go service. I'm new to Go and I just want to dockerize a little service that just connect to a mongodb instance.</p> <p>My code works fine locally. So here is my Dockerfile:</p> <pre><code># build stage FROM golang:alpine AS build-env RUN apk add --no-cache git ADD . . RUN go get -v -u go.mongodb.org/mongo-driver RUN go build -o mongotest # final stage FROM alpine WORKDIR /app COPY --from=build-env ./go/mongotest . RUN apk update &amp;&amp; apk add ca-certificates &amp;&amp; rm -rf /var/cache/apk/* EXPOSE 8000 CMD ["./mongotest"] </code></pre> <p>When I build it, I have this error message :</p> <pre class="lang-none prettyprint-override"><code>Step 6/18 : RUN go get -v -u go.mongodb.org/mongo-driver ---&gt; Running in 4c45c601800d Fetching https://go.mongodb.org/mongo-driver?go-get=1 Parsing meta tags from https://go.mongodb.org/mongo-driver?go-get=1 (status code 200) get "go.mongodb.org/mongo-driver": found meta tag get.metaImport{Prefix:"go.mongodb.org/mongo-driver", VCS:"git", RepoRoot:"https://github.com/mongodb/mongo-go-driver.git"} at https://go.mongodb.org/mongo-driver?go-get=1 go.mongodb.org/mongo-driver (download) package go.mongodb.org/mongo-driver: no Go files in /go/src/go.mongodb.org/mongo-driver The command '/bin/sh -c go get -v -u go.mongodb.org/mongo-driver' returned a non-zero code: 1 </code></pre> <p><code>no Go files in /go/src</code> ... ok, what can I do with that?</p> <p>The strange thing is that if I replace </p> <p><code>RUN go get -d -u go.mongodb.org/mongo-driver</code></p> <p>by </p> <p><code>RUN go get -d -u github.com/gorilla/mux</code></p> <p>it works!</p> <p>Is there a problem with mongo driver repo?</p> </div>

<div class="post-text" itemprop="text"> <p>I'm trying to get a projection for the number of elements in a documents array.</p> <pre><code>options.SetProjection(bson.M{ "foo": true, "nrOfBars": bson.M{ "$size": "$bars" }, }) </code></pre> <p><code>bars</code> is the fieldname of the array.<br> This query though always returns 0 instead of the arrays length.</p> <p>How do I correctly query for the length of the array with the new mongo-go-driver?</p> </div>

<div class="post-text" itemprop="text"> <p>Hi there :) I'm working on a golang app linked to mongo DB (I use the official driver: <code>mongo-go</code>) and here's my problem,I want to execute this function </p> <pre><code>db.rmTickets.find().forEach(function(doc) { doc.created=new Date(doc.created) doc.updated=new Date(doc.updated) doc.deadline=new Date(doc.deadline) doc.dateEstimationDelivery=new Date(doc.dateEstimationDelivery) doc.dateTransmitDemand=new Date(doc.dateTransmitDemand) doc.dateTransmitQuotation=new Date(doc.dateTransmitQuotation) doc.dateValidationQuotation=new Date(doc.dateValidationQuotation) doc.dateDeliveryCS=new Date(doc.dateDeliveryCS) db.rmTickets.save(doc) }) </code></pre> <p>I see on godoc that a <code>Database.RunCommand()</code> exists but I'm not sure about how to use it. If someone can help :) Thanks </p> </div>

<div class="post-text" itemprop="text"> <p>I want create a dynamic filter with the mongo-go-driver.</p> <p>For example, I have this documents:</p> <pre><code>{ "_id":"5d1231380a2a2b39a99c3ed1"}, "name":"flower.png", "colors":["#ffffff","#212121","#999999","#dbdbdb","#ff5252"], }, { "_id":"5d1231380a2a2b39a99c3ed0"}, "name":"image of go.jpg", "colors":["#dedede","#dfdfdf","#dddddd","#e0e0e0","#e2e2e2"], }, { "_id":"5d1231380a2a2b39a99c3ecf"}, "name":"bolket rulez.png", "colors":["#000000","#010101","#020202","#030303","#040404"], }, { "_id":"5d1231380a2a2b39a99c3ecf"}, "name":"bolket photo.png", "colors":["#ffffff","#010101","#020202","#030303","#040404"], } </code></pre> <p>Now I want all documents that have "bolket" in the name and "#ffffff" color.</p> <p>I have tryed with this filter:</p> <pre><code>filter := make(bson.D, 2) if f.Name != "" { filter = append(filter, bson.E{Key: "name", Value: bson.M{"$text": bson.M{"$search": f.Name}}}) } if f.Color != "" { filter = append(filter, bson.E{Key: "colors", Value: bson.M{"$in": f.Color}}) } </code></pre> <p>But with this filter I have this error: <code>(BadValue) unknown operator: $text </code></p> <p>How can I create a dynamic filter???</p> </div>

<div class="post-text" itemprop="text"> <p>I am very new to both Go and Mongodb and was writing my first rest-api with Go and Mongo. I am using <code>mongo-go-driver</code> and have the following <code>Modal</code> struct in Go </p> <pre><code>type Modal struct { Group []string `bson:"group" json:"group"` Hostname string `bson:"hostname" json:"hostname"` Overrides map[string]string `bson:"overrides" json:"overrides"` Excludes []string `bson:"excludes" json:"excludes"` } </code></pre> <p>I do not want to use the default <code>ObjectId</code> field provided by mongo-db as my primary key and instead would like to make the <code>Hostname</code> field as the primary key.</p> <p>If I make the type of <code>Hostname</code> field as <code>primitive.ObjectID</code>, then the <code>hostname</code> would be unique but its value will be randomly generated string by mongodb and not the actual hostname string value.</p> <p>So is there a way I can do this.</p> </div>

<div class="post-text" itemprop="text"> <p>I am trying to get some familiarity with the official <a href="https://godoc.org/go.mongodb.org/mongo-driver/mongo" rel="nofollow noreferrer">mongo-go-driver</a> and ran into an hour-long delay trying to figure out the right syntax for <code>UpdateOne</code>. </p> <p>My simplest full example follows (NOTE: in order to use this code you will need to substitute in your own user and server names as well as export the login password to the environment as MONGO_PW):</p> <pre class="lang-golang prettyprint-override"><code>package main import ( "context" "fmt" "os" "go.mongodb.org/mongo-driver/bson" "go.mongodb.org/mongo-driver/bson/primitive" "go.mongodb.org/mongo-driver/mongo" "go.mongodb.org/mongo-driver/mongo/options" ) type DB struct { User string Server string Database string Collection string Client *mongo.Client Ctx context.Context } var db = DB{ User: &lt;username&gt;, Server: &lt;server_IP&gt;, Database: "test", Collection: "movies", Ctx: context.TODO(), } type Movie struct { ID primitive.ObjectID `bson:"_id" json:"id"` Name string `bson:"name" json:"name"` Description string `bson:"description" json:"description"` } func main() { if err := db.Connect(); err != nil { fmt.Println("error: unable to connect") os.Exit(1) } fmt.Println("connected") // The code assumes the original entry for dunkirk is the following // {"Name":"dunkirk", "Description":"a world war 2 movie"} updatedMovie := Movie{ Name: "dunkirk", Description: "movie about the british evacuation in WWII", } res, err := db.UpdateByName(updatedMovie) if err != nil { fmt.Println("error updating movie:", err) os.Exit(1) } if res.MatchedCount &lt; 1 { fmt.Println("error: update did not match any documents") os.Exit(1) } } // UpdateByName changes the description for a movie identified by its name func (db *DB) UpdateByName(movie Movie) (*mongo.UpdateResult, error) { filter := bson.D{{"name", movie.Name}} res, err := db.Client.Database(db.Database).Collection(db.Collection).UpdateOne( db.Ctx, filter, movie, ) if err != nil { return nil, err } return res, nil } // Connect assumes that the database password is stored in the // environment variable MONGO_PW func (db *DB) Connect() error { pw, ok := os.LookupEnv("MONGO_PW") if !ok { fmt.Println("error: unable to find MONGO_PW in the environment") os.Exit(1) } mongoURI := fmt.Sprintf("mongodb+srv://%s:%s@%s", db.User, pw, db.Server) // Set client options and verify connection clientOptions := options.Client().ApplyURI(mongoURI) client, err := mongo.Connect(db.Ctx, clientOptions) if err != nil { return err } err = client.Ping(db.Ctx, nil) if err != nil { return err } db.Client = client return nil } </code></pre> <p>The function signature for <code>UpdateOne</code> from the package docs is:</p> <pre class="lang-golang prettyprint-override"><code>func (coll *Collection) UpdateOne(ctx context.Context, filter interface{}, update interface{}, opts ...*options.UpdateOptions) (*UpdateResult, error) </code></pre> <p>So I am clearly making some sort of mistake in creating the <code>update interface{}</code> argument to the function because I am presented with this error</p> <pre class="lang-none prettyprint-override"><code>error updating movie: update document must contain key beginning with '$' </code></pre> <p>The most popular answer <a href="https://stackoverflow.com/questions/38883285/error-the-update-operation-document-must-contain-atomic-operators-when-running">here</a> shows that I need to use a document sort of like this </p> <pre><code>{ $set: {"Name" : "The Matrix", "Decription" "Neo and Trinity kick butt" } } </code></pre> <p>but taken verbatim this will not compile in the mongo-go-driver.</p> <p>I think I need some form of a bson document to comply with the Go syntax. What is the best and/or most efficient syntax to create this bson document for the <code>update</code>?</p> </div>

<div class="post-text" itemprop="text"> <p>I am using the package: <code>"github.com/mongodb/mongo-go-driver/mongo"</code></p> <p>I am trying to use the following as specified in the <a href="https://godoc.org/github.com/mongodb/mongo-go-driver/mongo" rel="nofollow noreferrer">documentation</a>:</p> <pre><code>mongoContext, _ := context.WithTimeout(context.Background(), 10*time.Second) mongoClient, _ := mongo.Connect(mongoContext, "mongodb://localhost:27017") </code></pre> <p>However on the second line I get the error:</p> <pre><code>cannot use "mongodb://localhost:27017" (type string) as type *options.ClientOptions in argument to mongo.Connect </code></pre> <p>It seems the documentation doesn't match the implementation. Has anyone been successful?</p> <p><strong>The documentation states:</strong></p> <pre><code>//To do this in a single step, you can use the Connect function: ctx, _ := context.WithTimeout(context.Background(), 10*time.Second) client, err := mongo.Connect(ctx, "mongodb://localhost:27017") </code></pre> </div>

<div class="post-text" itemprop="text"> <p>I want to convert bson in <a href="https://github.com/mongodb/mongo-go-driver" rel="nofollow noreferrer">mongo-go-driver</a> to json effectively.</p> <p>I should take care to handle <code>NaN</code>, because <code>json.Marshal</code> fail if <code>NaN</code> exists in data.</p> <p>For instance, I want to convert below bson data to json.</p> <pre class="lang-golang prettyprint-override"><code>b, _ := bson.Marshal(bson.M{"a": []interface{}{math.NaN(), 0, 1}}) // How to convert b to json? </code></pre> <p>The below fails.</p> <pre class="lang-golang prettyprint-override"><code>// decode var decodedBson bson.M bson.Unmarshal(b, &amp;decodedBson) _, err := json.Marshal(decodedBson) if err != nil { panic(err) // it will be invoked // panic: json: unsupported value: NaN } </code></pre> </div>

<div class="post-text" itemprop="text"> <p>FindOneAndReplace may or may not replace the document in MongoDB. The response indicates that the operation succeeded, but looking into MongoDB it was not updated at all.</p> <p>The MongoDB server version is MongoDB server version: 3.2.0 This bug is reproducible in Ubuntu 16.04 and macOS Mojave. The target host is Azure CosmosDB.</p> <p>The driver version is mongo-go-driver@v0.0.17</p> <pre><code>func (s *Service) DeleteFileMetadata(ctx context.Context, req *pb.DocumentRequest) (*pb.DocumentResponse, error) { log.Println("[INFO] Requesting DeleteFileMetadata service") if ok := isStateAvailable(); !ok { log.Printf("[ERROR] %s ", errServiceUnavailable.Error()) return nil, status.Error(codes.Unavailable, errServiceUnavailable.Error()) } if err := refreshMongoDBConnection(mongoDBWriter, &amp;conf.DocumentDB.Writer); err != nil { log.Printf("[ERROR] %s ", err.Error()) return nil, status.Error(codes.Internal, err.Error()) } if req == nil { log.Printf("[ERROR] %s ", errNilRequest.Error()) return nil, status.Error(codes.InvalidArgument, errNilRequest.Error()) } fileMetadataParameters := req.GetFileMetadataParameters() if fileMetadataParameters == nil || fileMetadataParameters.GetDuid() == "" { log.Printf("[ERROR] %s ", errInvalidFileMetadataParameters.Error()) return nil, status.Error(codes.InvalidArgument, errInvalidFileMetadataParameters.Error()) } if err := ValidateDUID(fileMetadataParameters.GetDuid()); err != nil { log.Printf("[ERROR] %s ", err.Error()) return nil, status.Error(codes.InvalidArgument, err.Error()) } if err := ValidateUUID(fileMetadataParameters.GetUuid()); err != nil { log.Printf("[ERROR] %s ", err.Error()) return nil, status.Error(codes.InvalidArgument, err.Error()) } if err := ValidateFUID(fileMetadataParameters.GetFuid()); err != nil { log.Printf("[ERROR] %s ", err.Error()) return nil, status.Error(codes.InvalidArgument, err.Error()) } if fileMetadataParameters.Media &gt; pb.FileType_VIDEO { return nil, status.Error(codes.InvalidArgument, errMediaType.Error()) } log.Printf("[INFO] FileMetadataParameters: %v ", pretty.Sprint(req.GetFileMetadataParameters())) // Get the specific lock if it already exists, else make the lock lock, _ := duidClientLocker.LoadOrStore(fileMetadataParameters.GetDuid(), &amp;sync.RWMutex{}) // Lock lock.(*sync.RWMutex).Lock() // Unlock before the function exits defer lock.(*sync.RWMutex).Unlock() collection := mongoDBWriter.Database(conf.DocumentDB.Name).Collection(conf.DocumentDB.Collection) // Find all MongoDB documents for the specific uuid filter := bson.NewDocument( bson.EC.String("duid", fileMetadataParameters.GetDuid()), bson.EC.String("uuid", fileMetadataParameters.GetUuid()), ) bsonResult := collection.FindOne(context.Background(), filter) if bsonResult == nil { log.Printf("[ERROR] FindOne: %s ", errNoDocumentFound.Error()) return nil, status.Error(codes.InvalidArgument, errNoDocumentFound.Error()) } documentToUpdate := &amp;pb.Document{} if err := bsonResult.Decode(documentToUpdate); err != nil { log.Printf("[ERROR] Document not found, duid: %s - uuid: %s - err: %s ", fileMetadataParameters.GetDuid(), fileMetadataParameters.GetUuid(), err.Error()) return nil, status.Errorf(codes.InvalidArgument, "Document not found, duid: %s - uuid: %s", fileMetadataParameters.GetDuid(), fileMetadataParameters.GetUuid()) } log.Printf("[INFO] Document to update: %s ", pretty.Sprint(documentToUpdate)) switch fileMetadataParameters.Media { case pb.FileType_FILE: delete(documentToUpdate.GetFileUrlsMap(), fileMetadataParameters.GetFuid()) case pb.FileType_AUDIO: delete(documentToUpdate.GetAudioUrlsMap(), fileMetadataParameters.GetFuid()) case pb.FileType_IMAGE: delete(documentToUpdate.GetImageUrlsMap(), fileMetadataParameters.GetFuid()) case pb.FileType_VIDEO: delete(documentToUpdate.GetVideoUrlsMap(), fileMetadataParameters.GetFuid()) default: return nil, status.Error(codes.InvalidArgument, errMediaType.Error()) } documentToUpdate.UpdateTimestamp = time.Now().UTC().Unix() // option to return the the document after update option := findopt.ReplaceOneBundle{} result := collection.FindOneAndReplace(context.Background(), filter, documentToUpdate, option.ReturnDocument(mongoopt.After)) // Extract the updated MongoDB document if result == nil { log.Printf("[ERROR] Extracting updated document, duid: %s - uuid: %s ", documentToUpdate.GetDuid(), documentToUpdate.GetUuid()) return nil, status.Errorf(codes.Internal, "Extracting updated document duid: %s - uuid: %s", documentToUpdate.GetDuid(), documentToUpdate.GetUuid()) } document := &amp;pb.Document{} if err := result.Decode(document); err != nil { log.Printf("[ERROR] %s ", err.Error()) return nil, status.Errorf(codes.Internal, err.Error()) } log.Printf("[INFO] Updated document: %s ", pretty.Sprint(document)) log.Printf("[INFO] Success deleting file metadata in document, duid: %s - uuid: %s - fuid: %s ", document.GetDuid(), document.GetUuid(), fileMetadataParameters.GetFuid()) return &amp;pb.DocumentResponse{ Status: &amp;pb.DocumentResponse_Code{Code: uint32(codes.OK)}, Message: codes.OK.String(), Data: document, }, nil } </code></pre> <p>I expect that response reflects the actual state of the data in the MongoDB server.</p> <p>Let us say I want to delete a filemetadata with fuid of <code>05ce38e7-a29a-485f-bf20-eef3501867f0</code></p> <p>I get this response indicating that it was deleted. The response was decoded from <code>result := collection.FindOneAndReplace(context.Background(), filter, documentToUpdate, option.ReturnDocument(mongoopt.After))</code></p> <pre><code> ImageUrlsMap: {217706a5-2f88-4eb2-8a93-c1426c5ac944: "https://hwscdevstorage.blob.core.windows.net/images/hulkgif.png", 4ff30392-8ec8-45a4-ba94-5e22c4a686df: "https://hwscdevstorage.blob.core.windows.net/images/Rotating_earth_(large).gif"}, AudioUrlsMap: {4ff30392-8ec8-45a4-ba94-5e22c4a686df: "https://hwscdevstorage.blob.core.windows.net/audios/Milad Hosseini - Deli Asheghetam [128].mp3", 8fe5fea7-f683-4198-8c94-f27601a5e2d0: "https://hwscdevstorage.blob.core.windows.net/audios/Seger_Conga_CaboMexico_Tag_Acousonde_20140313_112313_8000_3_BreedingMigrating.wav"}, VideoUrlsMap: {4ff30392-8ec8-45a4-ba94-5e22c4a686de: "https://hwscdevstorage.blob.core.windows.net/videos/videoplayback.wmv", 4ff30392-8ec8-45a4-ba94-5e22c4a686df: "https://hwscdevstorage.blob.core.windows.net/videos/videoplayback.mp4", e525ca9c-9813-4286-abda-8bd0eb6e94b4: "https://hwscdevstorage.blob.core.windows.net/videos/pusheen.mp4"}, FileUrlsMap: {13df1afa-4eee-470e-b9e2-60b2a7584994: "https://hwscdevstorage.blob.core.windows.net/videos/videoplayback.wmv", 4ff30392-8ec8-45a4-ba94-5e22c4a686df: "https://hwscdevstorage.blob.core.windows.net/videos/videoplayback.mp4", b7a16e10-ac03-468f-9b6d-dcc684d1147f: "https://hwscdevstorage.blob.core.windows.net/videos/pusheen.mp4"}, RecordTimestamp: 1514764800, CreateTimestamp: 1539831496, UpdateTimestamp: 1546183549, IsPublic: true, XXX_NoUnkeyedLiteral: {}, XXX_unrecognized: [], XXX_sizecache: 0} 2018/12/30 07:25:49 [INFO] Success deleting file metadata in document, duid: 1ChHfmKs8GX7D1XVf61lwVdisWf - uuid: 0XXXXSNJG0MQJHBF4QX1EFD6Y3 - fuid: 05ce38e7-a29a-485f-bf20-eef3501867f0 </code></pre> <p>But if I go to Azure CosmosDB or in my local server, it is still there. <a href="https://i.stack.imgur.com/dfknK.png" rel="nofollow noreferrer">screenshot</a></p> </div>

<div class="post-text" itemprop="text"> <p>How can I filter fields with the mongo-go-driver. Tried it with findopt.Projection but no success. </p> <pre><code>type fields struct { _id int16 } s := bson.NewDocument() filter := bson.NewDocument(bson.EC.ObjectID("_id", starterId)) var opts []findopt.One opts = append(opts, findopt.Projection(fields{ _id: 0, })) staCon.collection.FindOne(nil, filter, opts...).Decode(s) </code></pre> <p>In the end, I want to suppress the field "_id". But the documents didn't change.</p> </div>

<div class="post-text" itemprop="text"> <p>I'm trying to do an aggregation with mongo-go-driver (MongoDB team driver for Golang) and I can't see what I'm doing wrong here: </p> <pre><code>// group group, e := bson.ParseExtJSONObject(` { "$group": { "_id":{ "ProductCode":"$ProductCode", "Dir":"$Dir", "WharehouseID":"$WharehouseID" } } } `) cursor, e := myCollection.Aggregate( context.Background(), group, ) // e output: "(Location40324) Unrecognized pipeline stage name: '_id'" </code></pre> <p>This is a mongodb error but if I execute this query in a mongodb native client I get the results and no error occurs. </p> </div>

<div class="post-text" itemprop="text"> <p>Go Version: 1.12.5</p> <p>I have this code which uses the node.js mongo driver</p> <pre><code>const MongoClient = require('mongodb').MongoClient; const uri = process.env.MONGO_HOST + "dbname?retryWrites=true"; const client = new MongoClient(uri, { useNewUrlParser: true }); client.connect(async (err) =&gt; { if (err) { throw err } const collection = client.db("dbname").collection("collectionName"); const cursor = collection.find() await cursor.forEach(console.log) // perform actions on the collection object client.close(); }); </code></pre> <p>Which works fine.</p> <p>Using the <code>mongo-go-driver</code>, I do:</p> <pre><code>client, err := mongo.NewClient(options.Client().ApplyURI(os.Getenv("MONGO_HOST") + "dbname?retryWrites=true") if err != nil { panic(err) } ctx, _ := context.WithTimeout(context.Background(), 10*time.Second) err = client.Connect(ctx) if err != nil { panic(err) } database := client.Database("dbname") collection := database.Collection("collectionName") res, err := collection.Find(context.Background(), bson.M{}, &amp;options.FindOptions{ Sort: bson.M{ "priority": -1, }, }) if err != nil { panic(err) } results := make([]structs.ResponseType, 0) err = res.All(context.Background(), &amp;results) if err != nil { panic(err) } </code></pre> <p>But this panics with:</p> <pre><code>panic: server selection error: server selection timeout current topology: Type: ReplicaSetNoPrimary </code></pre> <p>I am not running this inside a container/docker.</p> </div>

话不多说直接开干 目录 1-先去官网下载点击的MySQL的下载​ 2-配置初始化的my.ini文件的文件 3-初始化MySQL 4-安装MySQL服务 + 启动MySQL 服务 5-连接MySQL + 修改密码 先去官网下载点击的MySQL的下载 下载完成后解压 解压完是这个样子 配置初始化的my.ini文件的文件 ...

Python+OpenCV计算机视觉系统全面的介绍。

基于新的Vue.js 2.3版本， 目前新全的Vue.js教学视频，让你少走弯路，直达技术前沿！ 1. 包含Vue.js全家桶（vue.js、vue-router、axios、vuex、vue-cli、webpack、ElementUI等） 2. 采用笔记+代码案例的形式讲解，通俗易懂

navicat支持mysql的可视化操作，内涵激活码，不用再忍受弹框的痛苦。

这是我自己做的HTML期末大作业，花了很多时间，稍加修改就可以作为自己的作业了，而且也可以作为学习参考

【为什么学爬虫？】 &nbsp; &nbsp; &nbsp; &nbsp;1、爬虫入手容易，但是深入较难，如何写出高效率的爬虫，如何写出灵活性高可扩展的爬虫都是一项技术活。另外在爬虫过程中，经常容易遇到被反爬虫，比如字体反爬、IP识别、验证码等，如何层层攻克难点拿到想要的数据，这门课程，你都能学到！ &nbsp; &nbsp; &nbsp; &nbsp;2、如果是作为一个其他行业的开发者，比如app开发，web开发，学习爬虫能让你加强对技术的认知，能够开发出更加安全的软件和网站 【课程设计】 一个完整的爬虫程序，无论大小，总体来说可以分成三个步骤，分别是： 网络请求：模拟浏览器的行为从网上抓取数据。 数据解析：将请求下来的数据进行过滤，提取我们想要的数据。 数据存储：将提取到的数据存储到硬盘或者内存中。比如用mysql数据库或者redis等。 那么本课程也是按照这几个步骤循序渐进的进行讲解，带领学生完整的掌握每个步骤的技术。另外，因为爬虫的多样性，在爬取的过程中可能会发生被反爬、效率低下等。因此我们又增加了两个章节用来提高爬虫程序的灵活性，分别是： 爬虫进阶：包括IP代理，多线程爬虫，图形验证码识别、JS加密解密、动态网页爬虫、字体反爬识别等。 Scrapy和分布式爬虫：Scrapy框架、Scrapy-redis组件、分布式爬虫等。 通过爬虫进阶的知识点我们能应付大量的反爬网站，而Scrapy框架作为一个专业的爬虫框架，使用他可以快速提高我们编写爬虫程序的效率和速度。另外如果一台机器不能满足你的需求，我们可以用分布式爬虫让多台机器帮助你快速爬取数据。 &nbsp; 从基础爬虫到商业化应用爬虫，本套课程满足您的所有需求！ 【课程服务】 专属付费社群+每周三讨论会+1v1答疑

从事大数据与人工智能开发与实践约十年，钱老师亲自见证了大数据行业的发展与人工智能的从冷到热。事实证明，计算机技术的发展，算力突破，海量数据，机器人技术等，开启了第四次工业革命的序章。深度学习图像分类一直是人工智能的经典任务，是智慧零售、安防、无人驾驶等机器视觉应用领域的核心技术之一，掌握图像分类技术是机器视觉学习的重中之重。针对现有线上学习的特点与实际需求，我们开发了人工智能案例实战系列课程。打造：以项目案例实践为驱动的课程学习方式，覆盖了智能零售，智慧交通等常见领域，通过基础学习、项目案例实践、社群答疑，三维立体的方式，打造最好的学习效果。

时钟功能 还有闹钟功能，温湿度功能，整点报时功能 你值得拥有

做的是数据库课程设计，使用的php + MySQL，本来是黄金搭配也就没啥说的，推荐使用wamp服务器，里面有详细的使用说明，带有界面的啊！呵呵 不行的话，可以给我留言！

最近面试了一个31岁8年经验的程序猿，让我有点感慨，大龄程序猿该何去何从。

获取讲师答疑方式： 在付费视频第一节(触摸命令_ALL)片头有二维码及加群流程介绍 限时福利 原价99元，今日仅需39元！购课添加小助手（微信号：itxy41）按提示还可领取价值800元的编程大礼包！ 讲师介绍： 苏奕嘉&nbsp;前阿里UC项目工程师 脚本开发平台官方认证满级（六级）开发者。 我将如何教会你通过【定制脚本】赚到你人生的第一桶金？ 零基础程序定制脚本开发课程，是完全针对零脚本开发经验的小白而设计，课程内容共分为3大阶段： ①前期将带你掌握Q开发语言和界面交互开发能力； ②中期通过实战来制作有具体需求的定制脚本； ③后期将解锁脚本的更高阶玩法，打通任督二脉； ④应用定制脚本合法赚取额外收入的完整经验分享，带你通过程序定制脚本开发这项副业，赚取到你的第一桶金！

原价169，限时立减100元！ 系统掌握Python核心语法16点，轻松应对工作中80%以上的Python使用场景！ 69元=72讲+源码+社群答疑+讲师社群分享会&nbsp; 【哪些人适合学习这门课程？】 1）大学生，平时只学习了Python理论，并未接触Python实战问题； 2）对Python实用技能掌握薄弱的人，自动化、爬虫、数据分析能让你快速提高工作效率； 3）想学习新技术，如：人工智能、机器学习、深度学习等，这门课程是你的必修课程； 4）想修炼更好的编程内功，优秀的工程师肯定不能只会一门语言，Python语言功能强大、使用高效、简单易学。 【超实用技能】 从零开始 自动生成工作周报 职场升级 豆瓣电影数据爬取 实用案例 奥运冠军数据分析 自动化办公：通过Python自动化分析Excel数据并自动操作Word文档，最终获得一份基于Excel表格的数据分析报告。 豆瓣电影爬虫：通过Python自动爬取豆瓣电影信息并将电影图片保存到本地。 奥运会数据分析实战 简介：通过Python分析120年间奥运会的数据，从不同角度入手分析，从而得出一些有趣的结论。 【超人气老师】 二两 中国人工智能协会高级会员 生成对抗神经网络研究者 《深入浅出生成对抗网络：原理剖析与TensorFlow实现》一书作者 阿里云大学云学院导师 前大型游戏公司后端工程师 【超丰富实用案例】 0）图片背景去除案例 1）自动生成工作周报案例 2）豆瓣电影数据爬取案例 3）奥运会数据分析案例 4）自动处理邮件案例 5）github信息爬取/更新提醒案例 6）B站百大UP信息爬取与分析案例 7）构建自己的论文网站案例

这门课程基于主流的java8平台，由浅入深的详细讲解了java SE的开发技术，可以使java方向的入门学员，快速扎实的掌握java开发技术！

&nbsp; &nbsp; &nbsp; &nbsp; 本课程为Python数据挖掘方向的入门课程，课程主要以真实数据为基础，详细介绍数据挖掘入门的流程和使用Python实现pandas与numpy在数据挖掘方向的运用，并深入学习如何运用scikit-learn调用常用的数据挖掘算法解决数据挖掘问题，为进一步深入学习数据挖掘打下扎实的基础。

本课程从初学者角度出发，提供了C#从入门到成为程序开发高手所需要掌握的各方面知识和技术。 【课程特点】 1 由浅入深，编排合理； 2 视频讲解，精彩详尽； 3 丰富实例，轻松易学； 4 每章总结配有难点解析文档。 15大章节，228课时，1756分钟与你一同进步！

文章目录数据库基础知识为什么要使用数据库什么是SQL？什么是MySQL?数据库三大范式是什么mysql有关权限的表都有哪几个MySQL的binlog有有几种录入格式？分别有什么区别？数据类型mysql有哪些数据类型引擎MySQL存储引擎MyISAM与InnoDB区别MyISAM索引与InnoDB索引的区别？InnoDB引擎的4大特性存储引擎选择索引什么是索引？索引有哪些优缺点？索引使用场景（重点）...

利用数字电子计数知识设计并制作的数字电子钟(含multisim仿真)，该数字钟具有显示星期、24小时制时间、闹铃、整点报时、时间校准功能

想学好JAVA必须要报两万的培训班吗？ Java大神勿入 如果你： 零基础想学JAVA却不知道从何入手 看了一堆书和视频却还是连JAVA的环境都搭建不起来 囊中羞涩面对两万起的JAVA培训班不忍直视 在职没有每天大块的时间专门学习JAVA 那么恭喜你找到组织了，在这里有： 1. 一群志同道合立志学好JAVA的同学一起学习讨论JAVA 2. 灵活机动的学习时间完成特定学习任务+每日编程实战练习 3. 热心助人的助教和讲师及时帮你解决问题，不按时完成作业小心助教老师的家访哦 上一张图看看前辈的感悟： &nbsp; &nbsp; 大家一定迫不及待想知道什么是极简JAVA学习营了吧，下面就来给大家说道说道： 什么是极简JAVA学习营？ 1. 针对Java小白或者初级Java学习者； 2. 利用9天时间，每天1个小时时间； 3.通过 每日作业 / 组队PK / 助教答疑 / 实战编程 / 项目答辩 / 社群讨论 / 趣味知识抢答等方式让学员爱上学习编程 ， 最终实现能独立开发一个基于控制台的‘库存管理系统’ 的学习模式 极简JAVA学习营是怎么学习的？ &nbsp; 如何报名？ 只要购买了极简JAVA一：JAVA入门就算报名成功！ &nbsp;本期为第四期极简JAVA学习营，我们来看看往期学员的学习状态： 作业看这里~ &nbsp; 助教的作业报告是不是很专业 不交作业打屁屁 助教答疑是不是很用心 &nbsp; 有奖抢答大家玩的很嗨啊 &nbsp; &nbsp; 项目答辩终于开始啦 &nbsp; 优秀者的获奖感言 &nbsp; 这是答辩项目的效果 &nbsp; &nbsp; 这么细致的服务，这么好的氛围，这样的学习效果，需要多少钱呢？ 不要1999，不要199，不要99，只要9.9 是的你没听错，只要9.9以上所有就都属于你了 如果你： 1、&nbsp;想学JAVA没有基础 2、&nbsp;想学JAVA没有整块的时间 3、&nbsp;想学JAVA没有足够的预算 还等什么？赶紧报名吧，抓紧抢位，本期只招300人，错过只有等时间待定的下一期了 &nbsp; 报名请加小助手微信：eduxy-1 &nbsp; &nbsp;

董付国系列教材《Python程序设计基础》、《Python程序设计（第2版）》、《Python可以这样学》配套视频，讲解Python 3.5.x和3.6.x语法、内置对象用法、选择与循环以及函数设计与使用、lambda表达式用法、字符串与正则表达式应用、面向对象编程、文本文件与二进制文件操作、目录操作与系统运维、异常处理结构。

文章目录Java概述何为编程什么是Javajdk1.5之后的三大版本JVM、JRE和JDK的关系什么是跨平台性？原理是什么Java语言有哪些特点什么是字节码？采用字节码的最大好处是什么什么是Java程序的主类？应用程序和小程序的主类有何不同？Java应用程序与小程序之间有那些差别？Java和C++的区别Oracle JDK 和 OpenJDK 的对比基础语法数据类型Java有哪些数据类型switc...

机器学习实战系列套餐以实战为出发点，帮助同学们快速掌握机器学习领域必备经典算法原理并结合Python工具包进行实战应用。建议学习顺序：1.Python必备工具包：掌握实战工具 2.机器学习算法与实战应用：数学原理与应用方法都是必备技能 3.数据挖掘实战：通过真实数据集进行项目实战。按照下列课程顺序学习即可！ 课程风格通俗易懂，用最接地气的方式带领大家轻松进军机器学习！提供所有课程代码，PPT与实战数据，有任何问题欢迎随时与我讨论。

发现网上很多Java面试题都没有答案，所以花了很长时间搜集整理出来了这套Java面试题大全，希望对大家有帮助哈~ 本套Java面试题大全，全的不能再全，哈哈~ 一、Java 基础 1. JDK 和 JRE 有什么区别？ JDK：Java Development Kit 的简称，java 开发工具包，提供了 java 的开发环境和运行环境。 JRE：Java Runtime Environ...

已经连续五年参加大厂校招、社招的技术面试工作，简历看的不下于万份 这篇文章会用实例告诉你，什么是差的程序员简历！ 疫情快要结束了，各个公司也都开始春招了，作为即将红遍大江南北的新晋UP主，那当然要为小伙伴们做点事（手动狗头）。 就在公众号里公开征简历，义务帮大家看，并一一点评。《启舰：春招在即，义务帮大家看看简历吧》 一石激起千层浪，三天收到两百多封简历。 花光了两个星期的所有空闲时...

深度学习系列课程从深度学习基础知识点开始讲解一步步进入神经网络的世界再到卷积和递归神经网络，详解各大经典网络架构。实战部分选择当下最火爆深度学习框架PyTorch与Tensorflow/Keras，全程实战演示框架核心使用与建模方法。项目实战部分选择计算机视觉与自然语言处理领域经典项目，从零开始详解算法原理，debug模式逐行代码解读。适合准备就业和转行的同学们加入学习！ 建议按照下列课程顺序来进行学习 （1）掌握深度学习必备经典网络架构 （2）深度框架实战方法 （3）计算机视觉与自然语言处理项目实战。（按照课程排列顺序即可）

本课程为HoloLens2开发入门教程，讲解部署开发环境，安装VS2019，Unity版本，Windows SDK，创建Unity项目，讲解如何使用MRTK，编辑器模拟手势交互，打包VS工程并编译部署应用到HoloLens上等。

本文的面试题如下： Redis 持久化机制 缓存雪崩、缓存穿透、缓存预热、缓存更新、缓存降级等问题 热点数据和冷数据是什么 Memcache与Redis的区别都有哪些？ 单线程的redis为什么这么快 redis的数据类型，以及每种数据类型的使用场景，Redis 内部结构 redis的过期策略以及内存淘汰机制【～】 Redis 为什么是单线程的，优点 如何解决redis的并发竞争key问题 Red...

该套餐共包含从C小白到C++到MFC的全部课程，整套学下来绝对成为一名C++大牛！！！

这是武汉理工大学计算机学院数据结构与算法综合实验课程的第三次项目：欢乐连连看(C++ & MFC)迭代开发代码。运行环境：VS2017。已经实现功能：开始游戏、消子、判断胜负、提示、重排、计时、帮助。

YOLOv3是一种基于深度学习的端到端实时目标检测方法，以速度快见长。本课程将手把手地教大家使用labelImg标注和使用YOLOv3训练自己的数据集。课程分为三个小项目：足球目标检测（单目标检测）、梅西目标检测（单目标检测）、足球和梅西同时目标检测（两目标检测）。 本课程的YOLOv3使用Darknet，在Ubuntu系统上做项目演示。包括：安装Darknet、给自己的数据集打标签、整理自己的数据集、修改配置文件、训练自己的数据集、测试训练出的网络模型、性能统计(mAP计算和画出PR曲线)和先验框聚类。 Darknet是使用C语言实现的轻型开源深度学习框架，依赖少，可移植性好，值得深入探究。 除本课程《YOLOv3目标检测实战：训练自己的数据集》外，本人推出了有关YOLOv3目标检测的系列课程，请持续关注该系列的其它课程视频，包括： 《YOLOv3目标检测实战：交通标志识别》 《YOLOv3目标检测：原理与源码解析》 《YOLOv3目标检测：网络模型改进方法》 敬请关注并选择学习！

uboot-2015-07最新代码，喜欢的朋友请拿去