Cannot create index for MongoDB replica set: ReplicaSetNoPrimary - mongodb

Question

I am writing integration testing for my Go program. When I try to initiate my MongoDB (with Docker) running in replica set, it raise error:
server selection error: server selection timeout, current topology:
{
Type: ReplicaSetNoPrimary,
Servers: [
{
Addr: b3ec1125321a:27017,
Type: Unknown,
Last error: connection() error occurred during connection handshake: dial tcp: lookup b3ec1125321a on 10.225.109.87:53: no such host
},
]
}
So I try to create a minimal runnable code as below with comment:
package main
import (
"bytes"
"context"
"errors"
"fmt"
"net"
"os/exec"
"time"
"go.mongodb.org/mongo-driver/bson"
"go.mongodb.org/mongo-driver/mongo"
"go.mongodb.org/mongo-driver/mongo/options"
)
// getDockerPath returns the path for docker.
func getDockerPath() (string, error) {
return exec.LookPath("docker")
}
// getPort returns a useable port. (should use it as soon as you can)
func getPort() (int, error) {
l, err := net.Listen("tcp", ":0")
if err != nil {
return 0, fmt.Errorf("listen to port 0: %w", err)
}
defer l.Close()
return l.Addr().(*net.TCPAddr).Port, nil
}
// runMongo will run a MongoDB container in docker.
func runMongo(ctx context.Context) error {
dockerPath, err := getDockerPath()
if err != nil {
return fmt.Errorf("get docker path: %w", err)
}
mongoPort, err := getPort()
if err != nil {
return fmt.Errorf("get mongo port: %w", err)
}
mongoURL := fmt.Sprintf("mongodb://127.0.0.1:%d", mongoPort)
fmt.Printf("Starting a mongoDB listening on %s\n\n", mongoURL)
// Run MongoDB - build command and run.
args := []string{
"run", "-d", "-p", fmt.Sprintf("%d:27017", mongoPort),
"mongo",
"mongod", "--replSet=rs0",
}
startCmd := exec.CommandContext(ctx, dockerPath, args...)
stdout := &bytes.Buffer{}
startCmd.Stdout = stdout
if err := startCmd.Run(); err != nil {
return fmt.Errorf("run MongoDB container by docker: %w", err)
}
// Get the Docker container name.
containerName, err := stdout.ReadString('\n')
for err != nil {
containerName, err = stdout.ReadString('\n')
}
containerName = containerName[:6]
// **********************************************************************
// NOTICE: When I remove the code below to initiate the MongoDB's Replica
// Set. And remove the argument `--replSet rs0`, it works.
// **********************************************************************
//
// Initiate Mongo's Replica Set.
args = []string{
"exec", containerName,
"mongo", "--eval", "rs.initiate();",
}
err = errors.New("in loop")
for err != nil {
<-time.After(1 * time.Second)
initCmd := exec.CommandContext(ctx, dockerPath, args...)
fmt.Println(initCmd)
err = initCmd.Run()
if err != nil {
fmt.Println(err)
}
}
// Init MongoDB before use it.
client, err := mongo.Connect(ctx, options.Client().ApplyURI(mongoURL))
if err != nil {
return fmt.Errorf("cannot connect to MongoDB: %w", err)
}
indexName := "Namespace's name's unique index"
True := true
index, err := client.Database("tmp").Collection("namespace").Indexes().CreateOne(ctx, mongo.IndexModel{
Keys: bson.D{{Key: "name", Value: 1}},
Options: &options.IndexOptions{
Name: &indexName,
Unique: &True,
},
})
if err != nil {
return fmt.Errorf("create index for namespace: %w", err)
}
fmt.Println(index)
return nil
}
func main() {
err := runMongo(context.Background())
if err != nil {
fmt.Printf("Fail to run MongoDB: %v\n", err)
}
}
When I try to run, it throw an error:
$ go run .
Starting a mongoDB listening on mongodb://127.0.0.1:29597
/usr/bin/docker exec b3ec11 mongo --eval rs.initiate();
Fail to run MongoDB: create index for namespace: server selection error: server selection timeout, current topology: { Type: ReplicaSetNoPrimary, Servers: [{ Addr: b3ec1125321a:27017, Type: Unknown, Last error: connection() error occurred during connection handshake: dial tcp: lookup b3ec1125321a on 10.225.109.87:53: no such host }, ] }
I try to search on Google. But still cannot find a solution.
UPDATE: I can use mongosh to do it without any error:
$ mongosh mongodb://127.0.0.1:29597
> use tmp
> ns = db.getCollection("namespace")
> ns.createIndex({name: 1}, {unique: true, name: "Namespace's name's unique index"})
And this really worry me a lot - I cannot get why I can use mongosh but not the go-driver of MongoDB.
It tells me that now it is ReplicaSetNoPrimary. But I try to use mongosh to connect it and run rs.isMaster() - it tells me that the only running MongoDB node IS the master node.

Answer 1

I try to let the MongoDB use the network host but not the bridge, and then it works:
--- another.go 2022-08-28 17:14:58.536381918 +0800
+++ main.go 2022-08-28 17:16:06.193467707 +0800
## -40,13 +40,13 ##
return fmt.Errorf("get mongo port: %w", err)
}
mongoURL := fmt.Sprintf("mongodb://127.0.0.1:%d", mongoPort)
- fmt.Printf("Starting a mongoDB listening on %s\n\n", mongoURL)
+ fmt.Printf("Starting a mongoDB listening on %s [on host network]\n\n", mongoURL)
// Run MongoDB - build command and run.
args := []string{
- "run", "-d", "-p", fmt.Sprintf("%d:27017", mongoPort),
+ "run", "-d", "--net=host",
"mongo",
- "mongod", "--replSet=rs0",
+ "mongod", "--replSet=rs0", fmt.Sprintf("--port=%d", mongoPort),
}
startCmd := exec.CommandContext(ctx, dockerPath, args...)
stdout := &bytes.Buffer{}
## -70,7 +70,7 ##
// Initiate Mongo's Replica Set.
args = []string{
"exec", containerName,
- "mongo", "--eval", "rs.initiate();",
+ "mongo", "--eval", "rs.initiate();", mongoURL,
}
err = errors.New("in loop")
for err != nil {
But I still do not know why I cannot let it work in bridge network. [Waiting for another answer still...]