Initial commit

go.mod

@@ -0,0 +1,11 @@
+module check_restic
+
+go 1.17
+
+require github.com/pkg/sftp v1.13.4
+
+require (
+	github.com/kr/fs v0.1.0 // indirect
+	golang.org/x/crypto v0.0.0-20220214200702-86341886e292 // indirect
+	golang.org/x/sys v0.0.0-20220209214540-3681064d5158 // indirect
+)

go.sum

@@ -0,0 +1,21 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/kr/fs v0.1.0 h1:Jskdu9ieNAYnjxsi0LbQp1ulIKZV1LAFgK1tWhpZgl8=
+github.com/kr/fs v0.1.0/go.mod h1:FFnZGqtBN9Gxj7eW1uZ42v5BccTP0vu6NEaFoC2HwRg=
+github.com/pkg/sftp v1.13.4 h1:Lb0RYJCmgUcBgZosfoi9Y9sbl6+LJgOIgk/2Y4YjMFg=
+github.com/pkg/sftp v1.13.4/go.mod h1:LzqnAvaD5TWeNBsZpfKxSYn1MbjWwOsCIAFFJbpIsK8=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/crypto v0.0.0-20210421170649-83a5a9bb288b/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
+golang.org/x/crypto v0.0.0-20220214200702-86341886e292 h1:f+lwQ+GtmgoY+A2YaQxlSOnDjXcQ7ZRLWOHbC6HtRqE=
+golang.org/x/crypto v0.0.0-20220214200702-86341886e292/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423185535-09eb48e85fd7/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158 h1:rm+CHSpPEEW2IsXUib1ThaHIjuBVZjxNgSKmBLFfD4c=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -0,0 +1,137 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"sort"
+	"time"
+
+	"github.com/pkg/sftp"
+)
+
+const (
+	OK       = 0
+	WARNING  = 1
+	CRITICAL = 2
+	UNKNOWN  = 3
+)
+
+var (
+	warning  = flag.Duration("warning", -1, "return WARNING if the lastest snapshot is older than the specified number of hours")
+	critical = flag.Duration("critical", -1, "return CRITICAL if the lastest snapshot is older than the specified number of hours")
+	repoPath = flag.String("repository", "", "path to restic repository on sftp target")
+	sftpHost = flag.String("host", "", "ssh host to be used for sftp connection")
+	sftpUser = flag.String("user", "", "ssh user to be used for sftp connection")
+	sftpPort = flag.String("port", "22", "ssh port to be used for sftp connection")
+)
+
+func parseArgs() error {
+	flag.Parse()
+	if *warning < 0 {
+		return fmt.Errorf("The option 'warning' needs to be set and greater than 0.")
+	}
+	if *critical < 0 {
+		return fmt.Errorf("The option 'critical' needs to be set and greater than 0.")
+	}
+	if *repoPath == "" {
+		return fmt.Errorf("The option 'repository' needs to be set.")
+	}
+	if *sftpHost == "" {
+		return fmt.Errorf("The option 'host' needs to be set.")
+	}
+	if *sftpUser == "" {
+		return fmt.Errorf("The option 'user' needs to be set.")
+	}
+	if *sftpPort == "" {
+		return fmt.Errorf("The option 'port' needs to be a valid port.")
+	}
+	return nil
+}
+
+func getStatusStr(status int) string {
+	switch status {
+	case OK:
+		return "OK"
+	case WARNING:
+		return "WARNING"
+	case CRITICAL:
+		return "CRITICAL"
+	default:
+		return "UNKNOWN"
+	}
+}
+
+func main() {
+	rc, msg := mainReturnWithStatus()
+	fmt.Printf("%s: %s\n", getStatusStr(rc), msg)
+	os.Exit(rc)
+}
+
+func mainReturnWithStatus() (int, string) {
+	err := parseArgs()
+	if err != nil {
+		return UNKNOWN, err.Error()
+	}
+
+	// Connect to a remote host and request the sftp subsystem via the 'ssh'
+	// command. This assumes that passwordless login is correctly configured.
+	cmd := exec.Command("ssh", *sftpHost, "-l", *sftpUser, "-p", *sftpPort, "-s", "sftp")
+
+	// send errors from ssh to stderr
+	cmd.Stderr = os.Stderr
+
+	// get stdin and stdout
+	wr, err := cmd.StdinPipe()
+	if err != nil {
+		return UNKNOWN, err.Error()
+	}
+	rd, err := cmd.StdoutPipe()
+	if err != nil {
+		return UNKNOWN, err.Error()
+	}
+
+	// start the process
+	if err := cmd.Start(); err != nil {
+		return UNKNOWN, err.Error()
+	}
+	defer cmd.Wait()
+
+	// open the SFTP session
+	client, err := sftp.NewClientPipe(rd, wr)
+	if err != nil {
+		return UNKNOWN, err.Error()
+	}
+	defer client.Close()
+
+	// get a list of all snapshots in the restic repository
+	files, err := client.ReadDir(*repoPath + "/snapshots")
+	if err != nil {
+		return UNKNOWN, err.Error()
+	}
+
+	if len(files) == 0 {
+		return CRITICAL, "no snapshots found"
+	}
+
+	// sort snapshots by modtime
+	sort.Slice(files, func(a, b int) bool {
+		return files[b].ModTime().Before(files[a].ModTime())
+	})
+
+	age := time.Now().Sub(files[0].ModTime())
+
+	// sanity check
+	if age < 0 {
+		return CRITICAL, "latest snapshot is in the future"
+	}
+	msg := fmt.Sprintf("latest snapshot created %s ago", age.Round(time.Second))
+	if age > *critical {
+		return CRITICAL, msg
+	} else if age > *warning {
+		return WARNING, msg
+	} else {
+		return OK, msg
+	}
+}