initClient uses bookmark if it exists

if options.Bookmark is set, initClient will now use
it to create a client from the bookmarked settings.

initClientUsingBookmark uses methods introduced in
previous commits. It constructs connection string
to db from Bookmark.Url if it exists. If not, it
uses other fields in Bookmark to construct the
connection string. An implication of this is that
the Url field of Bookmark takes precedence.

main.go

@@ -10,9 +10,11 @@ import (
 	"github.com/jessevdk/go-flags"
 
 	"github.com/sosedoff/pgweb/pkg/api"
+	"github.com/sosedoff/pgweb/pkg/bookmarks"
 	"github.com/sosedoff/pgweb/pkg/client"
 	"github.com/sosedoff/pgweb/pkg/command"
 	"github.com/sosedoff/pgweb/pkg/connection"
+	"github.com/sosedoff/pgweb/pkg/shared"
 	"github.com/sosedoff/pgweb/pkg/util"
 )
 
@@ -23,14 +25,48 @@ func exitWithMessage(message string) {
 	os.Exit(1)
 }
 
+func initClientUsingBookmark(bookmarkPath, bookmarkName string) (*client.Client, error) {
+	bookmark, err := bookmarks.GetBookmark(bookmarkPath, bookmarkName)
+	if err != nil {
+		return nil, err
+	}
+	opt, err := bookmark.ConvertToOptions()
+	if err != nil {
+		return nil, err
+	}
+	var connStr string
+	if opt.Url != "" { // if the bookmark has url set, use it
+		connStr = opt.Url
+	} else {
+		connStr, err = connection.BuildString(opt)
+		if err != nil {
+			return nil, fmt.Errorf("error building connection string: %v", err)
+		}
+	}
+	var ssh *shared.SSHInfo
+	if !bookmark.SSHInfoIsEmpty() {
+		ssh = &bookmark.Ssh
+	}
+	return client.NewFromUrl(connStr, ssh)
+}
+
 func initClient() {
-	if connection.IsBlank(command.Opts) {
+	if connection.IsBlank(command.Opts) && options.Bookmark == "" {
 		return
 	}
 
-	cl, err := client.New()
-	if err != nil {
-		exitWithMessage(err.Error())
+	var cl *client.Client
+	var err error
+	if options.Bookmark != "" {
+		cl, err = initClientUsingBookmark(bookmarks.Path(), options.Bookmark)
+		if err != nil {
+			exitWithMessage(err.Error())
+		}
+	} else {
+		cl, err = client.New()
+		if err != nil {
+			exitWithMessage(err.Error())
+		}
 	}
 
 	if command.Opts.Debug {