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feat(SSH): Add support for SSH endpoint (#473)

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* feat(SSH): Add support for SSH endpoint

This commit adds support for SSH endpoint monitoring. Users can now configure an endpoint to be monitored using an SSH command by prefixing the endpoint's URL with ssh:\\. The configuration options for an SSH endpoint include the username, password, and command to be executed on the remote server. In addition, two placeholders are supported for SSH endpoints: [CONNECTED] and [STATUS].

This commit also updates the README to include instructions on how to configure SSH endpoints and the placeholders that can be used in their conditions. The README has been updated to include the new SSH-related options in the endpoints[] configuration object.

Here's a summary of the changes made in this commit:

    Added support for SSH endpoint monitoring
    Updated the documentation to include instructions on how to configure SSH endpoints and the placeholders that can be used in their conditions
This commit is contained in:
Henry Barreto 2023-09-23 14:37:24 -03:00 committed by GitHub
parent 8fbfba2163
commit 05565e3d0a
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5 changed files with 260 additions and 1 deletions
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27
README.md
View file

@ -90,6 +90,7 @@ Have any feedback or questions? [Create a discussion](https://github.com/TwiN/ga
- [Monitoring a WebSocket endpoint](#monitoring-a-websocket-endpoint)
- [Monitoring an endpoint using ICMP](#monitoring-an-endpoint-using-icmp)
- [Monitoring an endpoint using DNS queries](#monitoring-an-endpoint-using-dns-queries)
- [Monitoring an endpoint using SSH](#monitoring-an-endpoint-using-ssh)
- [Monitoring an endpoint using STARTTLS](#monitoring-an-endpoint-using-starttls)
- [Monitoring an endpoint using TLS](#monitoring-an-endpoint-using-tls)
- [Monitoring domain expiration](#monitoring-domain-expiration)
@ -214,6 +215,9 @@ If you want to test it locally, see [Docker](#docker).
| `endpoints[].dns` | Configuration for an endpoint of type DNS. <br />See [Monitoring an endpoint using DNS queries](#monitoring-an-endpoint-using-dns-queries). | `""` |
| `endpoints[].dns.query-type` | Query type (e.g. MX) | `""` |
| `endpoints[].dns.query-name` | Query name (e.g. example.com) | `""` |
| `endpoints[].ssh` | Configuration for an endpoint of type SSH. <br />See [Monitoring an endpoint using SSH](#monitoring-an-endpoint-using-ssh). | `""` |
| `endpoints[].ssh.username` | SSH username (e.g. example) | Required `""` |
| `endpoints[].ssh.password` | SSH password (e.g. password) | Required `""` |
| `endpoints[].alerts[].type` | Type of alert. <br />See [Alerting](#alerting) for all valid types. | Required `""` |
| `endpoints[].alerts[].enabled` | Whether to enable the alert. | `true` |
| `endpoints[].alerts[].failure-threshold` | Number of failures in a row needed before triggering the alert. | `3` |
@ -1585,6 +1589,28 @@ There are two placeholders that can be used in the conditions for endpoints of t
- The placeholder `[DNS_RCODE]` resolves to the name associated to the response code returned by the query, such as
`NOERROR`, `FORMERR`, `SERVFAIL`, `NXDOMAIN`, etc.
### Monitoring an endpoint using SSH
You can monitor endpoints using SSH by prefixing `endpoints[].url` with `ssh:\\`:
```yaml
endpoints:
- name: ssh-example
url: "ssh://example.com:22" # port is optional. Default is 22.
ssh:
username: "username"
password: "password"
body: |
{
"command": "uptime"
}
interval: 1m
conditions:
- "[CONNECTED] == true"
- "[STATUS] == 0"
```
The following placeholders are supported for endpoints of type SSH:
- `[CONNECTED]` resolves to `true` if the SSH connection was successful, `false` otherwise
- `[STATUS]` resolves the exit code of the command executed on the remote server (e.g. `0` for success)
### Monitoring an endpoint using STARTTLS
If you have an email server that you want to ensure there are no problems with, monitoring it through STARTTLS
@ -1601,7 +1627,6 @@ endpoints:
- "[CERTIFICATE_EXPIRATION] > 48h"
```
### Monitoring an endpoint using TLS
Monitoring endpoints using SSL/TLS encryption, such as LDAP over TLS, can help detect certificate expiration:
```yaml

70
client/client.go
View file

@ -3,6 +3,7 @@ package client
import (
"crypto/tls"
"crypto/x509"
"encoding/json"
"errors"
"fmt"
"golang.org/x/net/websocket"
@ -17,6 +18,7 @@ import (
"github.com/TwiN/whois"
"github.com/ishidawataru/sctp"
ping "github.com/prometheus-community/pro-bing"
"golang.org/x/crypto/ssh"
)
var (
@ -161,6 +163,74 @@ func CanPerformTLS(address string, config *Config) (connected bool, certificate
return true, verifiedChains[0][0], nil
}
// CanCreateSSHConnection checks whether a connection can be established and a command can be executed to an address
// using the SSH protocol.
func CanCreateSSHConnection(address, username, password string, config *Config) (bool, *ssh.Client, error) {
var port string
if strings.Contains(address, ":") {
addressAndPort := strings.Split(address, ":")
if len(addressAndPort) != 2 {
return false, nil, errors.New("invalid address for ssh, format must be host:port")
}
address = addressAndPort[0]
port = addressAndPort[1]
} else {
port = "22"
}
cli, err := ssh.Dial("tcp", strings.Join([]string{address, port}, ":"), &ssh.ClientConfig{
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
User: username,
Auth: []ssh.AuthMethod{
ssh.Password(password),
},
Timeout: config.Timeout,
})
if err != nil {
return false, nil, err
}
return true, cli, nil
}
// ExecuteSSHCommand executes a command to an address using the SSH protocol.
func ExecuteSSHCommand(sshClient *ssh.Client, body string, config *Config) (bool, int, error) {
type Body struct {
Command string `json:"command"`
}
defer sshClient.Close()
var b Body
if err := json.Unmarshal([]byte(body), &b); err != nil {
return false, 0, err
}
sess, err := sshClient.NewSession()
if err != nil {
return false, 0, err
}
err = sess.Start(b.Command)
if err != nil {
return false, 0, err
}
defer sess.Close()
err = sess.Wait()
if err == nil {
return true, 0, nil
}
e, ok := err.(*ssh.ExitError)
if !ok {
return false, 0, err
}
return true, e.ExitStatus(), nil
}
// Ping checks if an address can be pinged and returns the round-trip time if the address can be pinged
//
// Note that this function takes at least 100ms, even if the address is 127.0.0.1

13
config.yaml
View file

@ -1,4 +1,17 @@
endpoints:
- name: ssh
group: core
url: "ssh://example.org"
ssh:
username: "example"
password: "example"
body: |
{
"command": "uptime"
}
interval: 1m
conditions:
- "[STATUS] == 0"
- name: front-end
group: core
url: "https://twin.sh/health"

45
core/endpoint.go
View file

@ -17,6 +17,7 @@ import (
"github.com/TwiN/gatus/v5/client"
"github.com/TwiN/gatus/v5/core/ui"
"github.com/TwiN/gatus/v5/util"
"golang.org/x/crypto/ssh"
)
type EndpointType string
@ -43,6 +44,7 @@ const (
EndpointTypeTLS EndpointType = "TLS"
EndpointTypeHTTP EndpointType = "HTTP"
EndpointTypeWS EndpointType = "WEBSOCKET"
EndpointTypeSSH EndpointType = "SSH"
EndpointTypeUNKNOWN EndpointType = "UNKNOWN"
)
@ -70,6 +72,10 @@ var (
// This is because the free whois service we are using should not be abused, especially considering the fact that
// the data takes a while to be updated.
ErrInvalidEndpointIntervalForDomainExpirationPlaceholder = errors.New("the minimum interval for an endpoint with a condition using the " + DomainExpirationPlaceholder + " placeholder is 300s (5m)")
// ErrEndpointWithoutSSHUsername is the error with which Gatus will panic if an endpoint with SSH monitoring is configured without a user.
ErrEndpointWithoutSSHUsername = errors.New("you must specify a username for each endpoint with SSH")
// ErrEndpointWithoutSSHPassword is the error with which Gatus will panic if an endpoint with SSH monitoring is configured without a password.
ErrEndpointWithoutSSHPassword = errors.New("you must specify a password for each endpoint with SSH")
)
// Endpoint is the configuration of a monitored
@ -121,6 +127,27 @@ type Endpoint struct {
// NumberOfSuccessesInARow is the number of successful evaluations in a row
NumberOfSuccessesInARow int `yaml:"-"`
// SSH is the configuration of SSH monitoring.
SSH *SSH `yaml:"ssh,omitempty"`
}
type SSH struct {
// Username is the username to use when connecting to the SSH server.
Username string `yaml:"username,omitempty"`
// Password is the password to use when connecting to the SSH server.
Password string `yaml:"password,omitempty"`
}
// Validate validates the endpoint
func (s *SSH) ValidateAndSetDefaults() error {
if s.Username == "" {
return ErrEndpointWithoutSSHUsername
}
if s.Password == "" {
return ErrEndpointWithoutSSHPassword
}
return nil
}
// IsEnabled returns whether the endpoint is enabled or not
@ -152,6 +179,8 @@ func (endpoint Endpoint) Type() EndpointType {
return EndpointTypeHTTP
case strings.HasPrefix(endpoint.URL, "ws://") || strings.HasPrefix(endpoint.URL, "wss://"):
return EndpointTypeWS
case strings.HasPrefix(endpoint.URL, "ssh://"):
return EndpointTypeSSH
default:
return EndpointTypeUNKNOWN
}
@ -228,6 +257,9 @@ func (endpoint *Endpoint) ValidateAndSetDefaults() error {
if err != nil {
return err
}
if endpoint.SSH != nil {
return endpoint.SSH.ValidateAndSetDefaults()
}
return nil
}
@ -350,6 +382,19 @@ func (endpoint *Endpoint) call(result *Result) {
result.AddError(err.Error())
return
}
} else if endpointType == EndpointTypeSSH {
var cli *ssh.Client
result.Connected, cli, err = client.CanCreateSSHConnection(strings.TrimPrefix(endpoint.URL, "ssh://"), endpoint.SSH.Username, endpoint.SSH.Password, endpoint.ClientConfig)
if err != nil {
result.AddError(err.Error())
return
}
result.Success, result.HTTPStatus, err = client.ExecuteSSHCommand(cli, endpoint.Body, endpoint.ClientConfig)
if err != nil {
result.AddError(err.Error())
return
}
result.Duration = time.Since(startTime)
} else {
response, err = client.GetHTTPClient(endpoint.ClientConfig).Do(request)
result.Duration = time.Since(startTime)

106
core/endpoint_test.go
View file

@ -256,6 +256,7 @@ func TestEndpoint_Type(t *testing.T) {
type args struct {
URL string
DNS *DNS
SSH *SSH
}
tests := []struct {
args args
@ -325,6 +326,16 @@ func TestEndpoint_Type(t *testing.T) {
},
want: EndpointTypeWS,
},
{
args: args{
URL: "ssh://example.com:22",
SSH: &SSH{
Username: "root",
Password: "password",
},
},
want: EndpointTypeSSH,
},
{
args: args{
URL: "invalid://example.org",
@ -454,6 +465,52 @@ func TestEndpoint_ValidateAndSetDefaultsWithDNS(t *testing.T) {
}
}
func TestEndpoint_ValidateAndSetDefaultsWithSSH(t *testing.T) {
tests := []struct {
name string
username string
password string
expectedErr error
}{
{
name: "fail when has no user",
username: "",
password: "password",
expectedErr: ErrEndpointWithoutSSHUsername,
},
{
name: "fail when has no password",
username: "username",
password: "",
expectedErr: ErrEndpointWithoutSSHPassword,
},
{
name: "success when all fields are set",
username: "username",
password: "password",
expectedErr: nil,
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
endpoint := &Endpoint{
Name: "ssh-test",
URL: "https://example.com",
SSH: &SSH{
Username: test.username,
Password: test.password,
},
Conditions: []Condition{Condition("[STATUS] == 0")},
}
err := endpoint.ValidateAndSetDefaults()
if err != test.expectedErr {
t.Errorf("expected error %v, got %v", test.expectedErr, err)
}
})
}
}
func TestEndpoint_ValidateAndSetDefaultsWithSimpleErrors(t *testing.T) {
scenarios := []struct {
endpoint *Endpoint
@ -680,6 +737,55 @@ func TestIntegrationEvaluateHealthForDNS(t *testing.T) {
}
}
func TestIntegrationEvaluateHealthForSSH(t *testing.T) {
tests := []struct {
name string
endpoint Endpoint
conditions []Condition
success bool
}{
{
name: "ssh-success",
endpoint: Endpoint{
Name: "ssh-success",
URL: "ssh://localhost",
SSH: &SSH{
Username: "test",
Password: "test",
},
Body: "{ \"command\": \"uptime\" }",
},
conditions: []Condition{Condition("[STATUS] == 0")},
success: true,
},
{
name: "ssh-failure",
endpoint: Endpoint{
Name: "ssh-failure",
URL: "ssh://localhost",
SSH: &SSH{
Username: "test",
Password: "test",
},
Body: "{ \"command\": \"uptime\" }",
},
conditions: []Condition{Condition("[STATUS] == 1")},
success: false,
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
test.endpoint.ValidateAndSetDefaults()
test.endpoint.Conditions = test.conditions
result := test.endpoint.EvaluateHealth()
if result.Success != test.success {
t.Errorf("Expected success to be %v, but was %v", test.success, result.Success)
}
})
}
}
func TestIntegrationEvaluateHealthForICMP(t *testing.T) {
endpoint := Endpoint{
Name: "icmp-test",