refactor: replace cli parser with kong (!88)

https://gitlab.com/hectorjsmith/fail2ban-prometheus-exporter/-/merge_requests/88

README.md

@@ -114,23 +114,29 @@ There are no configuration files.
 
 **CLI flags**
 ```
-usage: exporter [<flags>]
+🚀 Collect prometheus metrics from a running Fail2Ban instance
 
 Flags:
-  -h, --help     Show context-sensitive help (also try --help-long and --help-man).
+  -h, --help                          Show context-sensitive help.
-  -v, --version  show version info and exit
+  -v, --version                       Show version info and exit
-      --collector.f2b.socket="/var/run/fail2ban/fail2ban.sock"  
+      --web.listen-address=":9191"    Address to use for the metrics server
-                 path to the fail2ban server socket
+                                      ($F2B_WEB_LISTEN_ADDRESS)
-      --collector.textfile.directory=""  
+      --collector.f2b.socket="/var/run/fail2ban/fail2ban.sock"
-                 directory to read text files with metrics from
+                                      Path to the fail2ban server socket
-      --web.listen-address=":9191"  
+                                      ($F2B_COLLECTOR_SOCKET)
-                 address to use for the metrics server
+      --collector.f2b.exit-on-socket-connection-error
-      --web.basic-auth.username=""  
+                                      When set to true the exporter will immediately
-                 username to use to protect endpoints with basic auth
+                                      exit on a fail2ban socket connection error
-      --web.basic-auth.password=""  
+                                      ($F2B_EXIT_ON_SOCKET_CONN_ERROR)
-                 password to use to protect endpoints with basic auth
+      --collector.textfile.directory=STRING
-      --collector.f2b.exit-on-socket-connection-error  
+                                      Directory to read text files with metrics from
-                 when set to true the exporter will immediately exit on a fail2ban socket connection error
+                                      ($F2B_COLLECTOR_TEXT_PATH)
+      --web.basic-auth.username=STRING
+                                      Username to use to protect endpoints with basic auth
+                                      ($F2B_WEB_BASICAUTH_USER)
+      --web.basic-auth.password=STRING
+                                      Password to use to protect endpoints with basic auth
+                                      ($F2B_WEB_BASICAUTH_PASS)
 ```
 
 **Environment variables**

cfg/cfg.go

@@ -2,108 +2,68 @@ package cfg
 
 import (
 	"fmt"
-	"github.com/alecthomas/kingpin/v2"
 	"os"
+
+	"github.com/alecthomas/kong"
 )
 
-const (
+var cliStruct struct {
-	socketEnvName                = "F2B_COLLECTOR_SOCKET"
+	VersionMode          bool   `name:"version" short:"v" help:"Show version info and exit"`
-	fileCollectorPathEnvName     = "F2B_COLLECTOR_TEXT_PATH"
+	ServerAddress        string `name:"web.listen-address" env:"F2B_WEB_LISTEN_ADDRESS" help:"Address to use for the metrics server" default:"${default_address}"`
-	addressEnvName               = "F2B_WEB_LISTEN_ADDRESS"
+	F2bSocketPath        string `name:"collector.f2b.socket" env:"F2B_COLLECTOR_SOCKET" help:"Path to the fail2ban server socket" default:"${default_socket}"`
-	basicAuthUserEnvName         = "F2B_WEB_BASICAUTH_USER"
+	ExitOnSocketError    bool   `name:"collector.f2b.exit-on-socket-connection-error" env:"F2B_EXIT_ON_SOCKET_CONN_ERROR" help:"When set to true the exporter will immediately exit on a fail2ban socket connection error"`
-	basicAuthPassEnvName         = "F2B_WEB_BASICAUTH_PASS"
+	TextFileExporterPath string `name:"collector.textfile.directory" env:"F2B_COLLECTOR_TEXT_PATH" help:"Directory to read text files with metrics from"`
-	exitOnSocketConnErrorEnvName = "F2B_EXIT_ON_SOCKET_CONN_ERROR"
+	BasicAuthUser        string `name:"web.basic-auth.username" env:"F2B_WEB_BASICAUTH_USER" help:"Username to use to protect endpoints with basic auth"`
-)
+	BasicAuthPass        string `name:"web.basic-auth.password" env:"F2B_WEB_BASICAUTH_PASS" help:"Password to use to protect endpoints with basic auth"`
-
-type AppSettings struct {
-	VersionMode           bool
-	MetricsAddress        string
-	Fail2BanSocketPath    string
-	FileCollectorPath     string
-	BasicAuthProvider     *hashedBasicAuth
-	ExitOnSocketConnError bool
-}
-
-func init() {
-	kingpin.HelpFlag.Short('h')
 }
 
 func Parse() *AppSettings {
-	settings := &AppSettings{}
+	ctx := kong.Parse(
-	readParamsFromCli(settings)
+		&cliStruct,
-	settings.validateFlags()
+		kong.Vars{
+			"default_socket":  "/var/run/fail2ban/fail2ban.sock",
+			"default_address": ":9191",
+		},
+		kong.Name("fail2ban_exporter"),
+		kong.Description("🚀 Export prometheus metrics from a running Fail2Ban instance"),
+		kong.UsageOnError(),
+	)
+
+	validateFlags(ctx)
+	settings := &AppSettings{
+		VersionMode:           cliStruct.VersionMode,
+		MetricsAddress:        cliStruct.ServerAddress,
+		Fail2BanSocketPath:    cliStruct.F2bSocketPath,
+		FileCollectorPath:     cliStruct.TextFileExporterPath,
+		ExitOnSocketConnError: cliStruct.ExitOnSocketError,
+		BasicAuthProvider:     newHashedBasicAuth(cliStruct.BasicAuthUser, cliStruct.BasicAuthPass),
+	}
 	return settings
 }
 
-func readParamsFromCli(settings *AppSettings) {
+func validateFlags(cliCtx *kong.Context) {
-	versionMode := kingpin.
-		Flag("version", "show version info and exit").
-		Short('v').
-		Default("false").
-		Bool()
-	socketPath := kingpin.
-		Flag("collector.f2b.socket", "path to the fail2ban server socket").
-		Default("/var/run/fail2ban/fail2ban.sock").
-		Envar(socketEnvName).
-		String()
-	fileCollectorPath := kingpin.
-		Flag("collector.textfile.directory", "directory to read text files with metrics from").
-		Default("").
-		Envar(fileCollectorPathEnvName).
-		String()
-	address := kingpin.
-		Flag("web.listen-address", "address to use for the metrics server").
-		Default(":9191").
-		Envar(addressEnvName).
-		String()
-	rawBasicAuthUsername := kingpin.
-		Flag("web.basic-auth.username", "username to use to protect endpoints with basic auth").
-		Default("").
-		Envar(basicAuthUserEnvName).
-		String()
-	rawBasicAuthPassword := kingpin.
-		Flag("web.basic-auth.password", "password to use to protect endpoints with basic auth").
-		Default("").
-		Envar(basicAuthPassEnvName).
-		String()
-	rawExitOnSocketConnError := kingpin.
-		Flag("collector.f2b.exit-on-socket-connection-error", "when set to true the exporter will immediately exit on a fail2ban socket connection error").
-		Default("false").
-		Envar(exitOnSocketConnErrorEnvName).
-		Bool()
-
-	kingpin.Parse()
-
-	settings.VersionMode = *versionMode
-	settings.MetricsAddress = *address
-	settings.Fail2BanSocketPath = *socketPath
-	settings.FileCollectorPath = *fileCollectorPath
-	settings.setBasicAuthValues(*rawBasicAuthUsername, *rawBasicAuthPassword)
-	settings.ExitOnSocketConnError = *rawExitOnSocketConnError
-}
-
-func (settings *AppSettings) setBasicAuthValues(rawUsername, rawPassword string) {
-	settings.BasicAuthProvider = newHashedBasicAuth(rawUsername, rawPassword)
-}
-
-func (settings *AppSettings) validateFlags() {
 	var flagsValid = true
-	if !settings.VersionMode {
+	var messages = []string{}
-		if settings.Fail2BanSocketPath == "" {
+	if !cliStruct.VersionMode {
-			fmt.Println("error: fail2ban socket path must not be blank")
+		if cliStruct.F2bSocketPath == "" {
+			messages = append(messages, "error: fail2ban socket path must not be blank")
 			flagsValid = false
 		}
-		if settings.MetricsAddress == "" {
+		if cliStruct.ServerAddress == "" {
-			fmt.Println("error: invalid server address, must not be blank")
+			messages = append(messages, "error: invalid server address, must not be blank")
 			flagsValid = false
 		}
-		if (len(settings.BasicAuthProvider.username) > 0) != (len(settings.BasicAuthProvider.password) > 0) {
+		if (len(cliStruct.BasicAuthUser) > 0) != (len(cliStruct.BasicAuthPass) > 0) {
-			fmt.Println("error: to enable basic auth both the username and the password must be provided")
+			messages = append(messages, "error: to enable basic auth both the username and the password must be provided")
 			flagsValid = false
 		}
 	}
 	if !flagsValid {
-		kingpin.Usage()
+		cliCtx.PrintUsage(false)
+		fmt.Println()
+		for i := 0; i < len(messages); i++ {
+			fmt.Println(messages[i])
+		}
 		os.Exit(1)
 	}
 }

cfg/settings.go

@@ -0,0 +1,10 @@
+package cfg
+
+type AppSettings struct {
+	VersionMode           bool
+	MetricsAddress        string
+	Fail2BanSocketPath    string
+	FileCollectorPath     string
+	BasicAuthProvider     *hashedBasicAuth
+	ExitOnSocketConnError bool
+}

go.mod

@@ -3,14 +3,13 @@ module gitlab.com/hectorjsmith/fail2ban-prometheus-exporter
 go 1.20
 
 require (
-	github.com/alecthomas/kingpin/v2 v2.3.2
+	github.com/alecthomas/kong v0.7.1
 	github.com/kisielk/og-rek v1.2.0
 	github.com/nlpodyssey/gopickle v0.2.0
 	github.com/prometheus/client_golang v1.16.0
 )
 
 require (
-	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
@@ -18,7 +17,6 @@ require (
 	github.com/prometheus/client_model v0.4.0 // indirect
 	github.com/prometheus/common v0.44.0 // indirect
 	github.com/prometheus/procfs v0.11.0 // indirect
-	github.com/xhit/go-str2duration/v2 v2.1.0 // indirect
 	golang.org/x/sys v0.9.0 // indirect
 	google.golang.org/protobuf v1.30.0 // indirect
 )

go.sum

@@ -1,12 +1,11 @@
-github.com/alecthomas/kingpin/v2 v2.3.2 h1:H0aULhgmSzN8xQ3nX1uxtdlTHYoPLu5AhHxWrKI6ocU=
+github.com/alecthomas/assert/v2 v2.1.0 h1:tbredtNcQnoSd3QBhQWI7QZ3XHOVkw1Moklp2ojoH/0=
-github.com/alecthomas/kingpin/v2 v2.3.2/go.mod h1:0gyi0zQnjuFk8xrkNKamJoyUo382HRL7ATRpFZCw6tE=
+github.com/alecthomas/kong v0.7.1 h1:azoTh0IOfwlAX3qN9sHWTxACE2oV8Bg2gAwBsMwDQY4=
-github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 h1:s6gZFSlWYmbqAuRjVTiNNhvNRfY2Wxp9nhfyel4rklc=
+github.com/alecthomas/kong v0.7.1/go.mod h1:n1iCIO2xS46oE8ZfYCNDqdR0b0wZNrXAIAqro/2132U=
-github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137/go.mod h1:OMCwj8VM1Kc9e19TLln2VL61YJF0x1XFtfdL4JdbSyE=
+github.com/alecthomas/repr v0.1.0 h1:ENn2e1+J3k09gyj2shc0dHr/yjaWSHRlrJ4DPMevDqE=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
 github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-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/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
@@ -14,14 +13,13 @@ github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg
 github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
 github.com/kisielk/og-rek v1.2.0 h1:CTvDIin+YnetsSQAYbe+QNAxXU3B50C5hseEz8xEoJw=
 github.com/kisielk/og-rek v1.2.0/go.mod h1:6ihsOSzSAxR/65S3Bn9zNihoEqRquhDQZ2c6I2+MG3c=
 github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
 github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/nlpodyssey/gopickle v0.2.0 h1:4naD2DVylYJupQLbCQFdwo6yiXEmPyp+0xf5MVlrBDY=
 github.com/nlpodyssey/gopickle v0.2.0/go.mod h1:YIUwjJ2O7+vnBsxUN+MHAAI3N+adqEGiw+nDpwW95bY=
-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/prometheus/client_golang v1.16.0 h1:yk/hx9hDbrGHovbci4BY+pRMfSuuat626eFsHb7tmT8=
 github.com/prometheus/client_golang v1.16.0/go.mod h1:Zsulrv/L9oM40tJ7T815tM89lFEugiJ9HzIqaAx4LKc=
 github.com/prometheus/client_model v0.4.0 h1:5lQXD3cAg1OXBf4Wq03gTrXHeaV0TQvGfUooCfx1yqY=
@@ -30,11 +28,6 @@ github.com/prometheus/common v0.44.0 h1:+5BrQJwiBB9xsMygAB3TNvpQKOwlkc25LbISbrdO
 github.com/prometheus/common v0.44.0/go.mod h1:ofAIvZbQ1e/nugmZGz4/qCb9Ap1VoSTIO7x0VV9VvuY=
 github.com/prometheus/procfs v0.11.0 h1:5EAgkfkMl659uZPbe9AS2N68a7Cc1TJbPEuGzFuRbyk=
 github.com/prometheus/procfs v0.11.0/go.mod h1:nwNm2aOCAYw8uTR/9bWRREkZFxAUcWzPHWJq+XBB/FM=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
-github.com/xhit/go-str2duration/v2 v2.1.0 h1:lxklc02Drh6ynqX+DdPyp5pCKLUQpRT8bp8Ydu2Bstc=
-github.com/xhit/go-str2duration/v2 v2.1.0/go.mod h1:ohY8p+0f07DiV6Em5LKB0s2YpLtXVyJfNt1+BlmyAsU=
 golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.9.0 h1:KS/R3tvhPqvJvwcKfnBHJwwthS11LRhmM5D59eEXa0s=
 golang.org/x/sys v0.9.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -43,6 +36,3 @@ google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp0
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.30.0 h1:kPPoIgf3TsEvrm0PFe15JQ+570QVxYzEvvHqChK+cng=
 google.golang.org/protobuf v1.30.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=