feat: add cli parameters for db path and metrics port (#4)

Add support for configuring CLI parameters in the application using a new
`cfg` package. The `cfg` package exports an `AppSettings` struct that
contains the settings the application was run with.
Update the application to use the new CLI parameters to set the db to open
and the port to use for the metrics server.
Add support for setting the app version during build. The app includes a
`-version` flag to print the stored version data.
This commit is contained in:
Hector 2021-02-06 15:17:35 +00:00
parent 5e81a98162
commit 4f18bf35a8
3 changed files with 83 additions and 16 deletions

48
cfg/cfg.go Normal file
View File

@ -0,0 +1,48 @@
package cfg
import (
"flag"
"fmt"
"os"
)
const (
minServerPort = 1000
maxServerPort = 65535
)
type AppSettings struct {
VersionMode bool
MetricsPort int
Fail2BanDbPath string
}
func Parse() *AppSettings {
appSettings := &AppSettings{}
flag.BoolVar(&appSettings.VersionMode, "version", false, "show version info and exit")
flag.IntVar(&appSettings.MetricsPort, "port", 9191, "port to use for the metrics server")
flag.StringVar(&appSettings.Fail2BanDbPath, "db", "", "path to the fail2ban sqlite database")
flag.Parse()
appSettings.validateFlags()
return appSettings
}
func (settings *AppSettings) validateFlags() {
var flagsValid = true
if !settings.VersionMode {
if settings.Fail2BanDbPath == "" {
fmt.Println("missing flag 'db'")
flagsValid = false
}
if settings.MetricsPort < minServerPort || settings.MetricsPort > maxServerPort {
fmt.Printf("invalid server port, must be within %d and %d (found %d)\n",
minServerPort, maxServerPort, settings.MetricsPort)
flagsValid = false
}
}
if !flagsValid {
flag.Usage()
os.Exit(1)
}
}

View File

@ -10,7 +10,7 @@ const queryBannedIpsPerJail = "SELECT j.name, (SELECT COUNT(1) FROM bans b WHERE
type Fail2BanDB struct {
DatabasePath string
sqliteDB *sql.DB
sqliteDB *sql.DB
}
func MustConnectToDb(databasePath string) *Fail2BanDB {

View File

@ -1,7 +1,9 @@
package main
import (
"fail2ban-prometheus-exporter/cfg"
fail2banDb "fail2ban-prometheus-exporter/db"
"fmt"
_ "github.com/mattn/go-sqlite3"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
@ -12,7 +14,11 @@ import (
const namespace = "fail2ban"
var (
db = fail2banDb.MustConnectToDb("fail2ban.sqlite3")
version = "dev"
commit = "none"
date = "unknown"
builtBy = "unknown"
metricUp = prometheus.NewDesc(
prometheus.BuildFQName(namespace, "", "up"),
"Was the last fail2ban query successful.",
@ -31,6 +37,7 @@ var (
)
type Exporter struct {
db *fail2banDb.Fail2BanDB
}
func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
@ -43,12 +50,12 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
ch <- prometheus.MustNewConstMetric(
metricUp, prometheus.GaugeValue, 1,
)
collectBadIpsPerJailMetrics(ch)
collectBannedIpsPerJailMetrics(ch)
e.collectBadIpsPerJailMetrics(ch)
e.collectBannedIpsPerJailMetrics(ch)
}
func collectBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
jailNameToCountMap, err := db.CountBadIpsPerJail()
func (e *Exporter) collectBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
jailNameToCountMap, err := e.db.CountBadIpsPerJail()
if err != nil {
log.Print(err)
}
@ -60,8 +67,8 @@ func collectBadIpsPerJailMetrics(ch chan<- prometheus.Metric) {
}
}
func collectBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
jailNameToCountMap, err := db.CountBannedIpsPerJail()
func (e *Exporter) collectBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
jailNameToCountMap, err := e.db.CountBannedIpsPerJail()
if err != nil {
log.Print(err)
}
@ -73,12 +80,24 @@ func collectBannedIpsPerJailMetrics(ch chan<- prometheus.Metric) {
}
}
func main() {
log.Print("starting fail2ban exporter")
exporter := &Exporter{}
prometheus.MustRegister(exporter)
http.Handle("/metrics", promhttp.Handler())
log.Fatal(http.ListenAndServe(":9101", nil))
func printAppVersion() {
fmt.Println(version)
fmt.Printf(" build date: %s\r\n commit hash: %s\r\n built by: %s\r\n", date, commit, builtBy)
}
func main() {
appSettings := cfg.Parse()
if appSettings.VersionMode {
printAppVersion()
} else {
log.Print("starting fail2ban exporter")
exporter := &Exporter{
db: fail2banDb.MustConnectToDb(appSettings.Fail2BanDbPath),
}
prometheus.MustRegister(exporter)
http.Handle("/metrics", promhttp.Handler())
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", appSettings.MetricsPort), nil))
}
}