Files
litestream/cmd/litestream/replicate.go
2020-12-26 09:39:21 -07:00

115 lines
2.3 KiB
Go

package main
import (
"context"
"errors"
"flag"
"fmt"
"os"
"os/signal"
"github.com/benbjohnson/litestream"
)
type ReplicateCommand struct {
ConfigPath string
Config Config
// List of managed databases specified in the config.
DBs []*litestream.DB
}
func NewReplicateCommand() *ReplicateCommand {
return &ReplicateCommand{}
}
// Run loads all databases specified in the configuration.
func (c *ReplicateCommand) Run(ctx context.Context, args []string) (err error) {
fs := flag.NewFlagSet("litestream-replicate", flag.ContinueOnError)
registerConfigFlag(fs, &c.ConfigPath)
fs.Usage = c.Usage
if err := fs.Parse(args); err != nil {
return err
}
// Load configuration.
if c.ConfigPath == "" {
return errors.New("-config required")
}
config, err := ReadConfigFile(c.ConfigPath)
if err != nil {
return err
}
// Setup signal handler.
ctx, cancel := context.WithCancel(context.Background())
ch := make(chan os.Signal, 1)
signal.Notify(ch, os.Interrupt)
go func() { <-ch; cancel() }()
// Display version information.
fmt.Printf("litestream %s\n", Version)
if len(config.DBs) == 0 {
return errors.New("configuration must specify at least one database")
}
for _, dbConfig := range config.DBs {
db, err := newDBFromConfig(dbConfig)
if err != nil {
return err
}
// Open database & attach to program.
if err := db.Open(); err != nil {
return err
}
c.DBs = append(c.DBs, db)
}
// Notify user that initialization is done.
fmt.Printf("Initialized with %d databases.\n", len(c.DBs))
// Wait for signal to stop program.
<-ctx.Done()
signal.Reset()
// Gracefully close
if err := c.Close(); err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
return nil
}
// Close closes all open databases.
func (c *ReplicateCommand) Close() (err error) {
for _, db := range c.DBs {
if e := db.SoftClose(); e != nil {
fmt.Printf("error closing db: path=%s err=%s\n", db.Path(), e)
if err == nil {
err = e
}
}
}
return err
}
func (c *ReplicateCommand) Usage() {
fmt.Printf(`
The replicate command starts a server to monitor & replicate databases
specified in your configuration file.
Usage:
litestream replicate [arguments]
Arguments:
-config PATH
Specifies the configuration file. Defaults to %s
`[1:], DefaultConfigPath)
}