Add slasher config file flag (#5639)

* Add slasher config file

* shorter line

* fix package dependencies

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>

slasher/BUILD.bazel

@@ -23,6 +23,7 @@ go_library(
         "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_x_cray_logrus_prefixed_formatter//:go_default_library",
         "@in_gopkg_urfave_cli_v2//:go_default_library",
+        "@in_gopkg_urfave_cli_v2//altsrc:go_default_library",
     ],
 )
 
@@ -63,6 +64,7 @@ go_image(
         "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_x_cray_logrus_prefixed_formatter//:go_default_library",
         "@in_gopkg_urfave_cli_v2//:go_default_library",
+        "@in_gopkg_urfave_cli_v2//altsrc:go_default_library",
     ],
 )
 

slasher/main.go

@@ -16,6 +16,7 @@ import (
 	"github.com/sirupsen/logrus"
 	prefixed "github.com/x-cray/logrus-prefixed-formatter"
 	"gopkg.in/urfave/cli.v2"
+	"gopkg.in/urfave/cli.v2/altsrc"
 )
 
 var log = logrus.WithField("prefix", "main")
@@ -48,6 +49,7 @@ var appFlags = []cli.Flag{
 	cmd.LogFormat,
 	cmd.ClearDB,
 	cmd.ForceClearDB,
+	cmd.ConfigFileFlag,
 	debug.PProfFlag,
 	debug.PProfAddrFlag,
 	debug.PProfPortFlag,
@@ -73,6 +75,16 @@ func main() {
 	app.Flags = appFlags
 	app.Action = startSlasher
 	app.Before = func(ctx *cli.Context) error {
+		// Load any flags from file, if specified.
+		if ctx.IsSet(cmd.ConfigFileFlag.Name) {
+			if err := altsrc.InitInputSourceWithContext(
+				appFlags,
+				altsrc.NewYamlSourceFromFlagFunc(
+					cmd.ConfigFileFlag.Name))(ctx); err != nil {
+				return err
+			}
+		}
+
 		format := ctx.String(cmd.LogFormat.Name)
 		switch format {
 		case "text":

slasher/usage.go

@@ -54,6 +54,7 @@ var appHelpFlagGroups = []flagGroup{
 			cmd.LogFileName,
 			cmd.ForceClearDB,
 			cmd.ClearDB,
+			cmd.ConfigFileFlag,
 		},
 	},
 	{