The mongo adapter for MongoDB wraps the labix.org/v2/mgo
driver by Gustavo Niemeyer.
This adapter supports CRUD but does not currently supports transactions.
db tag. You must use bson tags instead.If you want to install the package with go get, you’ll need the bazaar
version control system.
You can install bzr like this:
sudo apt-get install bzr -y
After bazaar is installed, use go get to download and install the adapter.
go get upper.io/db.v1/mongo
The mongo.ConnectionURL{} struct is defined like this:
// ConnectionURL implements a MongoDB connection struct.
type ConnectionURL struct {
User string
Password string
Address db.Address
Database string
Options map[string]string
}
The db.Address interface can be satisfied by the db.Host(), db.HostPort()
or db.Cluster() functions.
Alternatively, a mongo.ParseURL() function is provided:
// ParseURL parses s into a ConnectionURL struct.
mongo.ParseURL(s string) (ConnectionURL, error)
You may use mongo.ConnectionURL as argument for db.Open().
To use this adapter, import upper.io/db.v1 and the upper.io/db.v1/mongo packages.
# main.go
package main
import (
"upper.io/db.v1"
"upper.io/db.v1/mongo"
)
Then, you can use the db.Open() method to connect to a MongoDB server:
var settings = mongo.ConnectionURL{
Address: db.Host("localhost"), // MongoDB hostname.
Database: "peanuts", // Database name.
User: "cbrown", // Optional user name.
Password: "snoopy", // Optional user password.
}
sess, err = db.Open(mongo.Adapter, settings)
The Go code below will add some rows to the “birthday” collection and then will print the same rows that were inserted.
// example.go
package main
import (
"fmt"
"log"
"time"
"upper.io/db.v1" // Imports the main db package.
"upper.io/db.v1/mongo" // Imports the mongo adapter.
)
var settings = mongo.ConnectionURL{
Database: `upperio_tests`, // Database name.
Address: db.Host("127.0.0.1"), // Host's IP.
}
type Birthday struct {
// Maps the "Name" property to the "name" column of the "birthday" table.
Name string `bson:"name"`
// Maps the "Born" property to the "born" column of the "birthday" table.
Born time.Time `bson:"born"`
}
func main() {
// Attemping to establish a connection to the database.
sess, err := db.Open(mongo.Adapter, settings)
if err != nil {
log.Fatalf("db.Open(): %q\n", err)
}
// Remember to close the database session.
defer sess.Close()
// Pointing to the "birthday" table.
birthdayCollection, err := sess.Collection("birthday")
if err != nil {
if err != db.ErrCollectionDoesNotExists {
log.Fatalf("Could not use collection: %q\n", err)
}
} else {
err = birthdayCollection.Truncate()
if err != nil {
log.Fatalf("Truncate(): %q\n", err)
}
}
// Inserting some rows into the "birthday" table.
birthdayCollection.Append(Birthday{
Name: "Hayao Miyazaki",
Born: time.Date(1941, time.January, 5, 0, 0, 0, 0, time.UTC),
})
birthdayCollection.Append(Birthday{
Name: "Nobuo Uematsu",
Born: time.Date(1959, time.March, 21, 0, 0, 0, 0, time.UTC),
})
birthdayCollection.Append(Birthday{
Name: "Hironobu Sakaguchi",
Born: time.Date(1962, time.November, 25, 0, 0, 0, 0, time.UTC),
})
// Let's query for the results we've just inserted.
var res db.Result
res = birthdayCollection.Find()
var birthday []Birthday
// Query all results and fill the birthday variable with them.
err = res.All(&birthday)
if err != nil {
log.Fatalf("res.All(): %q\n", err)
}
// Printing to stdout.
for _, birthday := range birthday {
fmt.Printf("%s was born in %s.\n", birthday.Name, birthday.Born.Format("January 2, 2006"))
}
}
Running the example above:
go run main.go
Expected output:
Hayao Miyazaki was born in January 5, 1941.
Nobuo Uematsu was born in March 21, 1959.
Hironobu Sakaguchi was born in November 25, 1962.
This driver implements the canonical IDSetter interface but it also implements the more specific ObjectIdIDSetter that you could use with an struct like this:
type artistWithObjectIdKey struct {
id bson.ObjectId
Name string
}
// This SetID() will be called after a successful Append().
func (artist *artistWithObjectIdKey) SetID(id bson.ObjectId) error {
artist.id = id
return nil
}