Allow URLs for replica config path

cmd/litestream/main.go

@@ -6,8 +6,10 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"net/url"
 	"os"
 	"os/user"
+	"path"
 	"path/filepath"
 	"strings"
 	"time"
@@ -106,6 +108,15 @@ type Config struct {
 	DBs []*DBConfig `yaml:"dbs"`
 }
 
+func (c *Config) Normalize() error {
+	for i := range c.DBs {
+		if err := c.DBs[i].Normalize(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // DefaultConfig returns a new instance of Config with defaults set.
 func DefaultConfig() Config {
 	return Config{
@@ -145,6 +156,10 @@ func ReadConfigFile(filename string) (Config, error) {
 	} else if err := yaml.Unmarshal(buf, &config); err != nil {
 		return config, err
 	}
+
+	if err := config.Normalize(); err != nil {
+		return config, err
+	}
 	return config, nil
 }
 
@@ -153,6 +168,15 @@ type DBConfig struct {
 	Replicas []*ReplicaConfig `yaml:"replicas"`
 }
 
+func (c *DBConfig) Normalize() error {
+	for i := range c.Replicas {
+		if err := c.Replicas[i].Normalize(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 type ReplicaConfig struct {
 	Type                   string        `yaml:"type"` // "file", "s3"
 	Name                   string        `yaml:"name"` // name of replica, optional.
@@ -168,6 +192,46 @@ type ReplicaConfig struct {
 	Bucket          string `yaml:"bucket"`
 }
 
+func (c *ReplicaConfig) Normalize() error {
+	// Expand path filename, if necessary.
+	if prefix := "~" + string(os.PathSeparator); strings.HasPrefix(c.Path, prefix) {
+		u, err := user.Current()
+		if err != nil {
+			return err
+		} else if u.HomeDir == "" {
+			return fmt.Errorf("cannot expand replica path, no home directory available")
+		}
+		c.Path = filepath.Join(u.HomeDir, strings.TrimPrefix(c.Path, prefix))
+	}
+
+	// Attempt to parse as URL. Ignore if it is not a URL or if there is no scheme.
+	u, err := url.Parse(c.Path)
+	if err != nil || u.Scheme == "" {
+		return nil
+	}
+
+	switch u.Scheme {
+	case "file":
+		u.Scheme = ""
+		c.Type = u.Scheme
+		c.Path = path.Clean(u.String())
+		return nil
+
+	case "s3":
+		c.Type = u.Scheme
+		c.Path = strings.TrimPrefix(path.Clean(u.Path), "/")
+		c.Bucket = u.Host
+		if u := u.User; u != nil {
+			c.AccessKeyID = u.Username()
+			c.SecretAccessKey, _ = u.Password()
+		}
+		return nil
+
+	default:
+		return fmt.Errorf("unrecognized replica type in path scheme: %s", c.Path)
+	}
+}
+
 // DefaultConfigPath returns the default config path.
 func DefaultConfigPath() string {
 	if v := os.Getenv("LITESTREAM_CONFIG"); v != "" {

cmd/litestream/replicate.go

@@ -13,6 +13,7 @@ import (
 	"os/signal"
 
 	"github.com/benbjohnson/litestream"
+	"github.com/benbjohnson/litestream/s3"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
@@ -75,12 +76,24 @@ func (c *ReplicateCommand) Run(ctx context.Context, args []string) (err error) {
 	}
 
 	// Notify user that initialization is done.
-	fmt.Printf("Initialized with %d databases.\n", len(c.DBs))
+	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)
+		fmt.Printf("serving metrics on http://localhost:%s/metrics\n", port)
 		go func() {
 			http.Handle("/metrics", promhttp.Handler())
 			http.ListenAndServe(config.Addr, nil)

replica.go

@@ -141,6 +141,11 @@ func (r *FileReplica) Type() string {
 	return "file"
 }
 
+// Path returns the path the replica was initialized with.
+func (r *FileReplica) Path() string {
+	return r.dst
+}
+
 // LastPos returns the last successfully replicated position.
 func (r *FileReplica) LastPos() Pos {
 	r.mu.RLock()