Add settings help for healthchecks

Signed-off-by: Knut Ahlers <knut@ahlers.me>

README.md

@@ -9,6 +9,15 @@ Usage of ipt-loadbalancer:
   -e, --enable-managed-chain   Modify PREROUTING / POSTROUTING chain to contain a jump to managed chain
       --log-level string       Log level (debug, info, warn, error, fatal) (default "info")
       --version                Prints current version and exits
+
+# ipt-loadbalancer help
+Supported sub-commands are:
+  checkhelp <checkType>  Display available settings for a check
+
+# ipt-loadbalancer checkhelp http
+Setting        Default      Description
+code           200          HTTP Status-Code to expect from the request
+...
 ```
 
 ### Main Configuration File
@@ -47,7 +56,8 @@ healthCheck:
   # in parallel
   interval: 2s
   # Settings defines parameters for the given health-check and are
-  # individual to the type.
+  # individual to the type. See the `checkhelp <type>` subcommand for
+  # all supported settings and their default values.
   settings:
     insecureTLS: true
     path: /healthz

cli_checkhelp.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"fmt"
+
+	"git.luzifer.io/luzifer/ipt-loadbalancer/pkg/healthcheck"
+	"github.com/Luzifer/go_helpers/v2/cli"
+	"github.com/fatih/color"
+	"github.com/rodaine/table"
+)
+
+func init() {
+	registry.Add(cli.RegistryEntry{
+		Description: "Display available settings for a check",
+		Name:        "checkhelp",
+		Params:      []string{"<checkType>"},
+		Run: func(args []string) error {
+			if len(args[1:]) < 1 {
+				return fmt.Errorf("usage: checkhelp <checkType>")
+			}
+
+			check := healthcheck.ByName(args[1])
+			if check == nil {
+				return fmt.Errorf("check %q not found", args[1])
+			}
+
+			headerFmt := color.New(color.FgGreen, color.Underline).SprintfFunc()
+			columnFmt := color.New(color.FgYellow).SprintfFunc()
+
+			tbl := table.New("Setting", "Default", "Description")
+			tbl.WithHeaderFormatter(headerFmt).WithFirstColumnFormatter(columnFmt)
+
+			for _, help := range check.Help() {
+				tbl.AddRow(help.Name, help.Default, help.Description)
+			}
+
+			tbl.Print()
+
+			return nil
+		},
+	})
+}

go.mod

@@ -6,16 +6,23 @@ require (
 	github.com/Luzifer/go_helpers/v2 v2.21.0
 	github.com/Luzifer/rconfig/v2 v2.4.0
 	github.com/coreos/go-iptables v0.7.0
+	github.com/fatih/color v1.16.0
 	github.com/pkg/errors v0.9.1
+	github.com/rodaine/table v1.1.0
 	github.com/sirupsen/logrus v1.9.3
 	gopkg.in/yaml.v3 v3.0.1
 )
 
+require (
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+)
+
 require (
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/mitchellh/hashstructure/v2 v2.0.2
 	github.com/spf13/pflag v1.0.5 // indirect
-	golang.org/x/sys v0.13.0 // indirect
+	golang.org/x/sys v0.14.0 // indirect
 	gopkg.in/validator.v2 v2.0.0-20210331031555-b37d688a7fb0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 )

go.sum

@@ -8,10 +8,21 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fatih/color v1.16.0 h1:zmkK9Ngbjj+K0yRhTVONQh1p/HknKYSlNT+vZCzyokM=
+github.com/fatih/color v1.16.0/go.mod h1:fL2Sau1YI5c0pdGEVCbKQbLXB6edEj1ZgiY4NijnWvE=
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-runewidth v0.0.9 h1:Lm995f3rfxdpd6TSmuVCHVb/QhupuXlYr8sCI/QdE+0=
+github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
 github.com/mitchellh/hashstructure/v2 v2.0.2 h1:vGKWl0YJqUNxE8d+h8f6NJLcCJrgbhC4NcD46KavDd4=
 github.com/mitchellh/hashstructure/v2 v2.0.2/go.mod h1:MG3aRVU/N29oo/V/IhBX8GR/zz4kQkprJgF2EVszyDE=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
@@ -19,6 +30,8 @@ github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/rodaine/table v1.1.0 h1:/fUlCSdjamMY8VifdQRIu3VWZXYLY7QHFkVorS8NTr4=
+github.com/rodaine/table v1.1.0/go.mod h1:Qu3q5wi1jTQD6B6HsP6szie/S4w1QUQ8pq22pz9iL8g=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
@@ -26,12 +39,15 @@ github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVs
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
+golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

main.go

@@ -9,6 +9,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 
+	"github.com/Luzifer/go_helpers/v2/cli"
 	"github.com/Luzifer/rconfig/v2"
 )
 
@@ -20,7 +21,8 @@ var (
 		VersionAndExit     bool   `flag:"version" default:"false" description:"Prints current version and exits"`
 	}{}
 
-	version = "dev"
+	registry = cli.New()
+	version  = "dev"
 )
 
 func initApp() error {
@@ -49,6 +51,16 @@ func main() {
 		os.Exit(0)
 	}
 
+	if len(rconfig.Args()) > 1 {
+		if err = registry.Call(rconfig.Args()[1:]); err != nil {
+			if errors.Is(err, cli.ErrHelpCalled) {
+				os.Exit(1)
+			}
+			logrus.WithError(err).Fatal("executing sub-command")
+		}
+		os.Exit(0)
+	}
+
 	confFile, err := config.Load(cfg.Config)
 	if err != nil {
 		logrus.WithError(err).Fatal("loading config file")