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package clients
import (
"context"
"fmt"
"runtime"
"strings"
"time"
"github.com/mimecast/dtail/internal/clients/handlers"
"github.com/mimecast/dtail/internal/clients/remote"
"github.com/mimecast/dtail/internal/config"
"github.com/mimecast/dtail/internal/omode"
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(ctx context.Context) (status int) {
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()}
connCtx, cancel := conn.Handler.WithCancel(ctx)
go conn.Start(connCtx, cancel, throttleCh, statsCh)
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))
}
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