Accept a negative number as logs since value

Typing "-2" will now show logs since now - 2 minutes.

Also, an error during logs command will not cause dry to become
unresponsive.

Fixes #82.

app/container_events.go

@@ -286,6 +286,7 @@ func (h *containersScreenEventHandler) handleCharacter(key rune, f func(eventHan
 				}, f)
 				return nil
 			}); err != nil {
+
 			h.dry.appmessage("There was an error showing logs: " + err.Error())
 		}
 	case 's', 'S': //stats
@@ -536,7 +537,7 @@ func (h *containersScreenEventHandler) showLogs(id string, withTimestamp bool, f
 			f(h)
 			return
 		}
-
+		since = curateLogsDuration(since)
 		logs, err := h.dry.dockerDaemon.Logs(id, since, withTimestamp)
 		if err == nil {
 			appui.Stream(logs, forwarder.events(), func() {
@@ -545,6 +546,7 @@ func (h *containersScreenEventHandler) showLogs(id string, withTimestamp bool, f
 				refreshScreen()
 			})
 		} else {
+			f(h)
 			h.dry.appmessage("Error showing container logs: " + err.Error())
 
 		}

app/misc.go

@@ -4,6 +4,7 @@ import (
 	"github.com/moncho/dry/appui"
 	"github.com/moncho/dry/ui"
 	termbox "github.com/nsf/termbox-go"
+	"strings"
 )
 
 func logsPrompt() *appui.Prompt {
@@ -34,3 +35,12 @@ func inspect(
 		return nil
 	}
 }
+
+func curateLogsDuration(s string) string {
+	neg := strings.Index(s, "-")
+	if neg >= 0 {
+		return s[neg+1:]
+	}
+	return s
+
+}

app/misc_test.go

@@ -0,0 +1,36 @@
+package app
+
+import "testing"
+
+func Test_curateLogsDuration(t *testing.T) {
+	type args struct {
+		s string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			"-2",
+			args{
+				"-2",
+			},
+			"2",
+		},
+		{
+			"2",
+			args{
+				"2",
+			},
+			"2",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := curateLogsDuration(tt.args.s); got != tt.want {
+				t.Errorf("curateLogsDuration() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

app/service_events.go

@@ -201,6 +201,7 @@ func (h *servicesScreenEventHandler) showLogs(withTimestamp bool, f func(eventHa
 		}
 
 		showServiceLogs := func(serviceID string) error {
+			since = curateLogsDuration(since)
 			logs, err := h.dry.dockerDaemon.ServiceLogs(serviceID, since, withTimestamp)
 			if err == nil {
 				appui.Stream(logs, forwarder.events(),
@@ -214,8 +215,8 @@ func (h *servicesScreenEventHandler) showLogs(withTimestamp bool, f func(eventHa
 			return err
 		}
 		if err := h.widget.OnEvent(showServiceLogs); err != nil {
-			h.dry.appmessage("There was an error showing service logs: " + err.Error())
 			f(h)
+			h.dry.appmessage("There was an error showing service logs: " + err.Error())
 		}
 	}()
 }