feat: support tls configuration

README.md

@@ -70,6 +70,48 @@ then it's up and healthy. If the value is 0, then it's down.
 `uptime_latency_seconds` indicates the time it took to do a HTTP request to that specified `endpoint_address`
 field in second.
 
+## Configuration file schema
+
+If you want to do config.json.
+
+```json
+{
+    "endpoints": [
+        {
+            "name": "string",
+            "address": "https://url",
+            "method": "GET",
+            "timeout": 123,
+            "successful_status_code": "2xx",
+            "inverse_status": false,
+            "tls_configuration": {
+                "certificate_authority_path": "/path/to/certificate_authority.pem",
+                "client_certificate_path": "/path/to/client_certificate.pem",
+                "client_key_path": "/path/to/client_key.pem",
+                "insecure_skip_verify": true
+            }
+        }
+    ]
+}
+```
+
+If you want to do config.yaml (or .yml if you prefer).
+
+```yaml
+endpoints:
+    - name: "string"
+      address: "https://url"
+      method: "GET"
+      timeout: 123
+      successful_status_code: 2xx
+      inverse_status: false
+      tls_configuration:
+        certificate_authority_path: "/path/to/certificate_authority.pem",
+        client_certificate_path: "/path/to/client_certificate.pem",
+        client_key_path: "/path/to/client_key.pem",
+        insecure_skip_verify: true
+```
+
 ## Build from source
 
 Install [Go](https://go.dev/dl).

config.go

@@ -22,6 +22,13 @@
 
 package main
 
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"os"
+)
+
 type Configuration struct {
 	Endpoints []Endpoint `required:"true"`
 }
@@ -31,6 +38,89 @@ type Endpoint struct {
 	Address              string           `required:"true"`
 	Method               string           `required:"false" default:"GET"`
 	Timeout              uint16           `required:"false" default:"30"`
-	SuccessfulStatusCode string `required:"false" default:"2xx"`
-	InverseStatus        bool   `required:"false" default:"false"`
+	SuccessfulStatusCode string           `required:"false" default:"2xx" yaml:"successful_status_code" json:"successful_status_code" toml:"successful_status_code"`
+	InverseStatus        bool             `required:"false" default:"false" yaml:"inverse_status" json:"inverse_status" toml:"inverse_status"`
+	TLSConfiguration     TLSConfiguration `required:"false" yaml:"tls_configuration" json:"tls_configuration" toml:"tls_configuration"`
+}
+
+type TLSConfiguration struct {
+	CertificateAuthorityPath string `required:"false" yaml:"certificate_authority_path" json:"certificate_authority_path" toml:"certificate_authority_path"`
+	ClientCertificatePath    string `required:"false" yaml:"client_certificate_path" json:"client_certificate_path" toml:"client_certificate_path"`
+	ClientKeyPath            string `required:"false" yaml:"client_key_path" json:"client_key_path" toml:"client_key_path"`
+	InsecureSkipVerify       bool   `required:"false" default:"false" yaml:"insecure_skip_verify" json:"insecure_skip_verify" toml:"insecure_skip_verify"`
+}
+
+type PreprocessedEndpoint struct {
+	Name                 string
+	Address              string
+	Method               string
+	Timeout              uint16
+	SuccessfulStatusCode string
+	InverseStatus        bool
+	TLSConfiguration     PreproccessedTLSConfiguration
+}
+
+type PreproccessedTLSConfiguration struct {
+	Certificates       []tls.Certificate
+	RootCA             *x509.CertPool
+	InsecureSkipVerify bool
+}
+
+func processConfiguration(endpoints []Endpoint) ([]PreprocessedEndpoint, error) {
+	var preprocessedEndpoints []PreprocessedEndpoint
+
+	for _, endpoint := range endpoints {
+		var certificates []tls.Certificate = nil
+		var rootCA *x509.CertPool = nil
+
+		if endpoint.TLSConfiguration.CertificateAuthorityPath != "" {
+			// Read CA file
+			file, err := os.ReadFile(endpoint.TLSConfiguration.CertificateAuthorityPath)
+			if err != nil {
+				return nil, fmt.Errorf("reading certificate authority file: %s", err.Error())
+			}
+
+			rootCA = x509.NewCertPool()
+			ok := rootCA.AppendCertsFromPEM(file)
+			if !ok {
+				return nil, fmt.Errorf("invalid pem format for certificate authority")
+			}
+		}
+
+		if endpoint.TLSConfiguration.ClientCertificatePath != "" && endpoint.TLSConfiguration.ClientKeyPath != "" {
+			// Read certificate file
+			certificateFile, err := os.ReadFile(endpoint.TLSConfiguration.ClientCertificatePath)
+			if err != nil {
+				return nil, fmt.Errorf("reading certificate file: %s", err.Error())
+			}
+
+			keyFile, err := os.ReadFile(endpoint.TLSConfiguration.ClientKeyPath)
+			if err != nil {
+				return nil, fmt.Errorf("reading key file: %s", err.Error())
+			}
+
+			certificate, err := tls.X509KeyPair(certificateFile, keyFile)
+			if err != nil {
+				return nil, fmt.Errorf("creating x509 key pair: %s", err.Error())
+			}
+
+			certificates = append(certificates, certificate)
+		}
+
+		preprocessedEndpoints = append(preprocessedEndpoints, PreprocessedEndpoint{
+			Name:                 endpoint.Name,
+			Address:              endpoint.Address,
+			Method:               endpoint.Method,
+			Timeout:              endpoint.Timeout,
+			SuccessfulStatusCode: endpoint.SuccessfulStatusCode,
+			InverseStatus:        endpoint.InverseStatus,
+			TLSConfiguration: PreproccessedTLSConfiguration{
+				Certificates:       certificates,
+				RootCA:             rootCA,
+				InsecureSkipVerify: endpoint.TLSConfiguration.InsecureSkipVerify,
+			},
+		})
+	}
+
+	return preprocessedEndpoints, nil
 }

config.yml

@@ -23,6 +23,9 @@
 endpoints:
   - name: "GitHub"
     address: https://github.com/healthz
+    tls_configuration:
+      insecure_skip_verify: true
+
   - name: "Reinaldy"
     address: https://code.reinaldyrafli.com
     timeout: 60

exporter.go

@@ -24,6 +24,7 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	"net/http"
 	"strconv"
 	"sync"
@@ -54,7 +55,7 @@ var (
 )
 
 type Exporter struct {
-	Endpoints []Endpoint
+	Endpoints []PreprocessedEndpoint
 	Logger    *onelog.Logger
 }
 
@@ -106,7 +107,7 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 	wg.Add(len(e.Endpoints))
 
 	for _, endpoint := range e.Endpoints {
-		go func(endpoint Endpoint) {
+		go func(endpoint PreprocessedEndpoint) {
 			defer wg.Done()
 
 			// Create HTTP calls
@@ -118,6 +119,13 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 
 			httpClient := http.Client{
 				Timeout: time.Duration(uint64(endpoint.Timeout) * 1e+9),
+				Transport: &http.Transport{
+					TLSClientConfig: &tls.Config{
+						Certificates:       endpoint.TLSConfiguration.Certificates,
+						RootCAs:            endpoint.TLSConfiguration.RootCA,
+						InsecureSkipVerify: endpoint.TLSConfiguration.InsecureSkipVerify,
+					},
+				},
 			}
 
 			response, err := httpClient.Do(request)

main.go

@@ -49,14 +49,21 @@ func main() {
 	var config Configuration
 	err := configor.Load(&config, *configFile)
 	if err != nil {
-		log.Fatalln(err)
+		log.Fatalln(err.Error())
 	}
 
+	preprocessedConfig, err := processConfiguration(config.Endpoints)
+	if err != nil {
+		log.Fatalln(err.Error())
+	}
+
+	log.Printf("%+v", preprocessedConfig)
+
 	// Initiate the logger instance. It should be zero-allocated, so we'll use onelog
 	logger := onelog.New(os.Stdout, onelog.ALL)
 
 	exporter := &Exporter{
-		Endpoints: config.Endpoints,
+		Endpoints: preprocessedConfig,
 		Logger:    logger,
 	}