feat: add healthcheck

Author: ItsNotGoodName

README.md

@@ -94,6 +94,18 @@ data_directory: smtpbridge_data
 # Python executable
 python_executable: python3
 
+# Healthcheck enables verification that the program has not crashed or lost network access
+# You can use a third party service such as healthchecks.io
+healthcheck:
+  # URL to fetch, empty means health checking is disabled
+  url: "" # (https://hc-ping.com/cb8bcf81-d3c4-4c98-85a6-734c3b7ddb2b, ...)
+
+  # Interval between each fetch
+  interval: 5m # (5m, 5h45m, ...)
+
+  # Run on startup
+  startup: false
+
 # Retention policy for envelopes and attachment files
 retention:
   # Retention policy for envelopes in database

cmd/smtpbridge/main.go

@@ -132,6 +132,18 @@ func run(flags *flag.FlagSet) lieut.Executor {
 				job.Execute(ctx)
 			}
 
+			if cfg.HealthcheckURL != "" {
+				job := cron.NewHealthcheck(cfg.HealthcheckURL)
+				trigger := quartz.NewSimpleTrigger(cfg.HealthcheckInterval)
+				if err := scheduler.ScheduleJob(ctx, job, trigger); err != nil {
+					return err
+				}
+
+				if cfg.HealthcheckStartup {
+					job.Execute(ctx)
+				}
+			}
+
 			return nil
 		}))
 

config/config.go

@@ -37,6 +37,9 @@ type Config struct {
 	CSRFSecretPath       string
 	SessionSecretPath    string
 	SessionsDirectory    string
+	HealthcheckURL       string
+	HealthcheckInterval  time.Duration
+	HealthcheckStartup   bool
 	HTTPDisable          bool
 	HTTPAddress          string
 	HTTPPort             uint16
@@ -61,6 +64,9 @@ type Raw struct {
 	RetentionEnvelopeCount  string `koanf:"retention.envelope_count"`
 	RetentionEnvelopeAge    string `koanf:"retention.envelope_age"`
 	RetentionAttachmentSize string `koanf:"retention.attachment_size"`
+	HealthcheckURL          string `koanf:"healthcheck.url"`
+	HealthcheckInterval     string `koanf:"healthcheck.interval"`
+	HealthcheckStartup      bool   `koanf:"healthcheck.startup"`
 	SMTPDisable             bool   `koanf:"smtp.disable"`
 	SMTPHost                string `koanf:"smtp.host"`
 	SMTPPort                uint16 `koanf:"smtp.port"`
@@ -97,21 +103,23 @@ type RawRule struct {
 }
 
 var RawDefault = struct {
-	TimeFormat         string `koanf:"time_format"`
-	MaxPayloadSize     string `koanf:"max_payload_size"`
-	DataDirectory      string `koanf:"data_directory"`
-	PythonExecutable   string `koanf:"python_executable"`
-	SMTPPort           uint16 `koanf:"smtp.port"`
-	SMTPMaxPayloadSize string `koanf:"smtp.max_payload_size"`
-	HTTPPort           uint16 `koanf:"http.port"`
+	HealthcheckInterval string `koanf:"healthcheck.interval"`
+	TimeFormat          string `koanf:"time_format"`
+	MaxPayloadSize      string `koanf:"max_payload_size"`
+	DataDirectory       string `koanf:"data_directory"`
+	PythonExecutable    string `koanf:"python_executable"`
+	SMTPPort            uint16 `koanf:"smtp.port"`
+	SMTPMaxPayloadSize  string `koanf:"smtp.max_payload_size"`
+	HTTPPort            uint16 `koanf:"http.port"`
 	// IMAPPort         uint16 `koanf:"imap.port"`
 }{
-	TimeFormat:         timeFormat12H,
-	SMTPMaxPayloadSize: "25 MB",
-	DataDirectory:      "smtpbridge_data",
-	PythonExecutable:   "python3",
-	SMTPPort:           1025,
-	HTTPPort:           8080,
+	HealthcheckInterval: "5m",
+	TimeFormat:          timeFormat12H,
+	SMTPMaxPayloadSize:  "25 MB",
+	DataDirectory:       "smtpbridge_data",
+	PythonExecutable:    "python3",
+	SMTPPort:            1025,
+	HTTPPort:            8080,
 	// IMAPPort:         10143,
 }
 
@@ -130,6 +138,10 @@ func WithFlagSet(flags *flag.FlagSet) *flag.FlagSet {
 	flags.String("python-executable", "", flagUsageString(RawDefault.PythonExecutable, "Python executable."))
 	flags.Bool("debug", false, flagUsageBool(false, "Run in debug mode."))
 
+	flags.String("healthcheck-url", "", flagUsageString("", "Healthcheck URL to fetch."))
+	flags.String("healthcheck-interval", "", flagUsageString(RawDefault.HealthcheckInterval, "Healthcheck interval between each fetch."))
+	flags.Bool("healthcheck-startup", false, flagUsageBool(false, "Healthcheck fetch on startup."))
+
 	flags.Bool("smtp-disable", false, flagUsageBool(false, "Disable SMTP server."))
 	flags.String("smtp-host", "", flagUsageString("", "SMTP host address to listen on."))
 	flags.Int("smtp-port", 0, flagUsageInt(int(RawDefault.SMTPPort), "SMTP port to listen on."))
@@ -306,7 +318,15 @@ func (p Parser) Parse(raw Raw) (Config, error) {
 
 	// imapAddress := raw.IMAPHost + ":" + strconv.Itoa(int(raw.IMAPPort))
 
+	healthcheckInterval, err := time.ParseDuration(raw.HealthcheckInterval)
+	if err != nil {
+		return Config{}, err
+	}
+
 	return Config{
+		HealthcheckURL:       raw.HealthcheckURL,
+		HealthcheckInterval:  healthcheckInterval,
+		HealthcheckStartup:   raw.HealthcheckStartup,
 		Debug:                raw.Debug,
 		TimeHourFormat:       timeHourFormat,
 		DatabasePath:         databasePath,

cron/cron.go

@@ -2,13 +2,15 @@ package cron
 
 import (
 	"context"
+	"net/http"
 
 	"github.com/ItsNotGoodName/smtpbridge/internal/core"
 	"github.com/ItsNotGoodName/smtpbridge/internal/trace"
 	"github.com/reugn/go-quartz/quartz"
 	"github.com/rs/zerolog/log"
 )
 
+// RetentionPolicy
 type RetentionPolicy struct {
 	app core.App
 }
@@ -34,6 +36,7 @@ func (r RetentionPolicy) Key() int {
 	return quartz.HashCode(r.Description())
 }
 
+// AttachmentOrphan
 type AttachmentOrphan struct {
 	app core.App
 }
@@ -58,3 +61,37 @@ func (r AttachmentOrphan) Execute(ctx context.Context) {
 func (r AttachmentOrphan) Key() int {
 	return quartz.HashCode(r.Description())
 }
+
+// Healthcheck
+type Healthcheck struct {
+	URL string
+}
+
+func NewHealthcheck(url string) Healthcheck {
+	return Healthcheck{
+		URL: url,
+	}
+}
+
+func (Healthcheck) Description() string {
+	return "healthcheck"
+}
+
+func (r Healthcheck) Execute(ctx context.Context) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, r.URL, nil)
+	if err != nil {
+		log.Err(err).Msg("Failed create HTTP request")
+		return
+	}
+
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		log.Err(err).Msg("Failed send HTTP request")
+		return
+	}
+	res.Body.Close()
+}
+
+func (r Healthcheck) Key() int {
+	return quartz.HashCode(r.Description())
+}