Files
litestream/cmd/litestream/replicate.go
Ben Johnson 7fb98df240 cleanup
2021-01-18 15:58:49 -07:00

152 lines
3.4 KiB
Go

package main
import (
"context"
"errors"
"flag"
"fmt"
"log"
"net"
"net/http"
_ "net/http/pprof"
"os"
"os/signal"
"github.com/benbjohnson/litestream"
"github.com/benbjohnson/litestream/s3"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
// ReplicateCommand represents a command that continuously replicates SQLite databases.
type ReplicateCommand struct {
ConfigPath string
Config Config
// List of managed databases specified in the config.
DBs []*litestream.DB
}
// 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)
verbose := fs.Bool("v", false, "verbose logging")
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
}
// Enable trace logging.
if *verbose {
litestream.Tracef = log.Printf
}
// Setup signal handler.
ctx, cancel := context.WithCancel(ctx)
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 {
fmt.Println("no databases specified in configuration")
}
for _, dbConfig := range config.DBs {
db, err := newDBFromConfig(&config, 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.
for _, db := range c.DBs {
fmt.Printf("initialized db: %s\n", db.Path())
for _, r := range db.Replicas {
switch r := r.(type) {
case *litestream.FileReplica:
fmt.Printf("replicating to: name=%q type=%q path=%q\n", r.Name(), r.Type(), r.Path())
case *s3.Replica:
fmt.Printf("replicating to: name=%q type=%q bucket=%q path=%q region=%q\n", r.Name(), r.Type(), r.Bucket, r.Path, r.Region)
default:
fmt.Printf("replicating to: name=%q type=%q\n", r.Name(), r.Type())
}
}
}
// Serve metrics over HTTP if enabled.
if config.Addr != "" {
_, port, _ := net.SplitHostPort(config.Addr)
fmt.Printf("serving metrics on http://localhost:%s/metrics\n", port)
go func() {
http.Handle("/metrics", promhttp.Handler())
if err := http.ListenAndServe(config.Addr, nil); err != nil {
log.Printf("cannot start metrics server: %s", err)
}
}()
}
// 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
}
// Usage prints the help screen to STDOUT.
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
-v
Enable verbose logging output.
`[1:], DefaultConfigPath())
}