initial commit

pkg/haproxy/haproxy.go

@@ -0,0 +1,67 @@
+package haproxy
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"sync"
+	"text/template"
+)
+
+type ServiceManager interface {
+	Reload()
+}
+
+type HAProxyManager struct {
+	sync.Mutex
+
+	configFile     string
+	serviceManager ServiceManager
+	template       *template.Template
+}
+
+func NewHAProxyManager(configFile string) (*HAProxyManager, error) {
+	t, err := template.New("haproxy").Parse(haproxyTemplate)
+	if err != nil {
+		return nil, err
+	}
+	return &HAProxyManager{
+		configFile:     configFile,
+		serviceManager: NewSystemdManager("haproxy"),
+		template:       t,
+	}, nil
+}
+
+func (ha *HAProxyManager) checkConfig(ctx context.Context, configFile string) error {
+	return exec.CommandContext(ctx, "haproxy", "-c", "-f", configFile).Run()
+}
+
+func (ha *HAProxyManager) UpdateConfig(ctx context.Context, lbs []config.LoadBalancer) error {
+	ha.Lock()
+	defer ha.Unlock()
+	tmp, err := ioutil.TempFile(os.TempDir(), "haproxy_")
+	if err != nil {
+		return err
+	}
+	defer tmp.Close()
+	defer os.Remove(tmp.Name())
+	err = ha.template.Execute(tmp, lbs)
+	if err != nil {
+		return err
+	}
+	err = ha.checkConfig(ctx, tmp.Name())
+	if err != nil {
+		return err
+	}
+	file, err := os.OpenFile(ha.configFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	err = ha.template.Execute(file, lbs)
+	if err != nil {
+		file.Close()
+		return err
+	}
+	file.Close()
+	return ha.serviceManager.Reload()
+}