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package app_test
import (
"fmt"
"io/ioutil"
"os"
"github.com/canonical/go-dqlite/v2/app"
)
// To start the first node of a dqlite cluster for the first time, its network
// address should be specified using the app.WithAddress() option.
//
// When the node is restarted a second time, the app.WithAddress() option might
// be omitted, since the node address will be persisted in the info.yaml file.
//
// The very first node has always the same ID (dqlite.BootstrapID).
func Example() {
dir, err := ioutil.TempDir("", "dqlite-app-example-")
if err != nil {
return
}
defer os.RemoveAll(dir)
node, err := app.New(dir, app.WithAddress("127.0.0.1:9001"))
if err != nil {
return
}
fmt.Printf("0x%x %s\n", node.ID(), node.Address())
if err := node.Close(); err != nil {
return
}
node, err = app.New(dir)
if err != nil {
return
}
defer node.Close()
fmt.Printf("0x%x %s\n", node.ID(), node.Address())
// Output: 0x2dc171858c3155be 127.0.0.1:9001
// 0x2dc171858c3155be 127.0.0.1:9001
}
// After starting the very first node, a second node can be started by passing
// the address of the first node using the app.WithCluster() option.
//
// In general additional nodes can be started by specifying one or more
// addresses of existing nodes using the app.Cluster() option.
//
// When the node is restarted a second time, the app.WithCluster() option might
// be omitted, since the node has already joined the cluster.
//
// Each additional node will be automatically assigned a unique ID.
func ExampleWithCluster() {
dir1, err := ioutil.TempDir("", "dqlite-app-example-")
if err != nil {
return
}
defer os.RemoveAll(dir1)
dir2, err := ioutil.TempDir("", "dqlite-app-example-")
if err != nil {
return
}
defer os.RemoveAll(dir2)
dir3, err := ioutil.TempDir("", "dqlite-app-example-")
if err != nil {
return
}
defer os.RemoveAll(dir3)
node1, err := app.New(dir1, app.WithAddress("127.0.0.1:9001"))
if err != nil {
return
}
defer node1.Close()
node2, err := app.New(dir2, app.WithAddress("127.0.0.1:9002"), app.WithCluster([]string{"127.0.0.1:9001"}))
if err != nil {
return
}
defer node2.Close()
node3, err := app.New(dir3, app.WithAddress("127.0.0.1:9003"), app.WithCluster([]string{"127.0.0.1:9001"}))
if err != nil {
return
}
fmt.Println(node1.ID() != node2.ID(), node1.ID() != node3.ID(), node2.ID() != node3.ID())
// true true true
// Restart the third node, the only argument we need to pass to
// app.New() is its dir.
id3 := node3.ID()
if err := node3.Close(); err != nil {
return
}
node3, err = app.New(dir3)
if err != nil {
return
}
defer node3.Close()
fmt.Println(node3.ID() == id3, node3.Address())
// true 127.0.0.1:9003
}
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