Release of DTail v1.0.0v1.0.0

1 files changed, 96 insertions, 0 deletions

diff --git a/clients/healthclient.go b/clients/healthclient.go
new file mode 100644
index 0000000..1fae99c
--- /dev/null
+++ b/clients/healthclient.go
@@ -0,0 +1,96 @@
+package clients
+
+import (
+	"dtail/clients/handlers"
+	"dtail/clients/remote"
+	"dtail/config"
+	"dtail/omode"
+	"fmt"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+
+	gossh "golang.org/x/crypto/ssh"
+)
+
+// HealthClient is used for health checking (e.g. via Nagios)
+type HealthClient struct {
+	// Client operating mode
+	mode omode.Mode
+	// The remote server address
+	server string
+	// SSH user name
+	userName string
+	// SSH auth methods to use to connect to the remote servers.
+	sshAuthMethods []gossh.AuthMethod
+}
+
+// NewHealthClient returns a new healh client.
+func NewHealthClient(mode omode.Mode) (*HealthClient, error) {
+	c := HealthClient{
+		mode:     mode,
+		server:   fmt.Sprintf("%s:%d", config.Server.SSHBindAddress, config.Common.SSHPort),
+		userName: config.ControlUser,
+	}
+	c.initSSHAuthMethods()
+
+	return &c, nil
+}
+
+// Start the health client.
+func (c *HealthClient) Start(wg *sync.WaitGroup) (status int) {
+	defer wg.Done()
+	receive := make(chan string)
+
+	throttleCh := make(chan struct{}, runtime.NumCPU())
+	statsCh := make(chan struct{}, 1)
+
+	conn := remote.NewOneOffConnection(c.server, c.userName, c.sshAuthMethods)
+	conn.Handler = handlers.NewHealthHandler(c.server, receive)
+	conn.Commands = []string{c.mode.String()}
+
+	go conn.Start(throttleCh, statsCh)
+	defer conn.Stop()
+
+	for {
+		select {
+		case data := <-receive:
+			// Parse recieved data.
+			s := strings.Split(data, "|")
+			message := s[len(s)-1]
+			if strings.HasPrefix(message, "done;") {
+				return
+			}
+
+			// Set severity.
+			s = strings.Split(message, ":")
+			switch s[0] {
+			case "OK":
+			case "WARNING":
+				if status < 1 {
+					status = 1
+				}
+			case "CRITICAL":
+				status = 2
+			case "UNKNOWN":
+				status = 3
+			default:
+				fmt.Printf("CRITICAL: Unexpected server response: '%s'\n", message)
+				status = 2
+				return
+			}
+			fmt.Print(message)
+
+		case <-time.After(time.Second * 2):
+			status = 2
+			fmt.Println("CRITICAL: Could not communicate with DTail server")
+			return
+		}
+	}
+}
+
+// Initialize SSH auth methods.
+func (c *HealthClient) initSSHAuthMethods() {
+	c.sshAuthMethods = append(c.sshAuthMethods, gossh.Password(config.ControlUser))
+}