add netbox version compatibility check

.gitignore

@@ -2,3 +2,4 @@ coverage.out
 config.yml
 netbox_sd
 bin/
+.testing

Makefile

@@ -1,4 +1,4 @@
-VERSION = v1.0.0
+VERSION = v1.0.1
 COMMIT = $(shell git rev-list -1 HEAD | cut -c1-10)
 DIRTY = $(shell git diff --quiet || echo '-dirty')
 DATE = $(shell date -u +%a,\ %d\ %b\ %Y\ %H:%M:%S\ %Z)

README.md

@@ -178,10 +178,6 @@ metrics (additional to golang specific ones) are exposed:
 - netbox_sd_api_status (200, 403, etc)
 - netbox_sd_api_duration_seconds
 
-## Changelog
-### v1.0.0
- - initial open source release
-
 ## Noteworthy Mention
 Special thanks goes out to [WIIT AG](https://www.wiit.cloud/en/) for open sourcing netbox_sd and netbox-go. This tool
 has been developed and used in production for multiple years now internally and WIIT AG was kind enough to release this

go.mod

@@ -21,6 +21,7 @@ require (
 )
 
 require (
+	github.com/Masterminds/semver v1.5.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/klauspost/compress v1.17.9 // indirect
 	github.com/kr/text v0.2.0 // indirect

go.sum

@@ -1,3 +1,5 @@
+github.com/Masterminds/semver v1.5.0 h1:H65muMkzWKEuNDnfl9d70GUjFniHKHRbFPGBuZ3QEww=
+github.com/Masterminds/semver v1.5.0/go.mod h1:MB6lktGJrhw8PrUyiEoblNEGEQ+RzHPF078ddwwvV3Y=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=

pkg/netbox/consts.go

@@ -32,4 +32,6 @@ const (
 	StatusIPDeprecated string = "DEPRECATED"
 	StatusIPDHCP       string = "DHCP"
 	StatusIPSLAAC      string = "SLAAC"
+
+	compatibleNetboxVersion string = ">=3.4.5,<4.0.0"
 )

pkg/netbox/netbox.go

@@ -43,6 +43,7 @@ package netbox
 
 import (
 	"crypto/tls"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"log"
@@ -99,6 +100,11 @@ type Name struct {
 	Name string `json:"name"`
 }
 
+// NetboxStatus contains details about a Netbox installation.
+type netboxStatus struct {
+	Version string `json:"netbox-version"`
+}
+
 // New creates a new Client to interact with a netbox API. baseURL must point to a valid Netbox installation (without
 // /api or /graphql at the end) while token must be a valid Netbox API key. WithTLS enabled TLS for HTTP transport while
 // tlsInsecure can be set to allow any certificate to be accepted.
@@ -191,11 +197,12 @@ func New(baseURL, token, promNamespace string, withTLS bool, tlsInsecure bool) (
 // token. If connection and token are okay, nil is returned.
 func (client *Client) VerifyConnectivity() error {
 	var (
-		resp response
-		err  error
+		resp   response
+		err    error
+		status netboxStatus
 	)
 
-	resp, err = client.get("/dcim/devices/?limit=1")
+	resp, err = client.get("/api/status/")
 	if err != nil {
 		return fmt.Errorf("failed to query api: %w", err)
 	}
@@ -206,6 +213,15 @@ func (client *Client) VerifyConnectivity() error {
 		return ErrInvalidToken
 	}
 
+	err = json.Unmarshal(resp.RawBody().Bytes(), &status)
+	if err != nil {
+		return fmt.Errorf("failed to unmarshal json from response body buffer: %w", err)
+	}
+
+	if !netboxIsCompatible(status.Version) {
+		return fmt.Errorf("detected incompatible Netbox version: v%s", status.Version)
+	}
+
 	return nil
 }
 

pkg/netbox/util.go

@@ -0,0 +1,28 @@
+package netbox
+
+import (
+	"fmt"
+
+	"github.com/Masterminds/semver"
+)
+
+// netboxIsCompatible returns true when a version string of Netbox is supported.
+func netboxIsCompatible(version string) bool {
+	var (
+		compatibleVersion *semver.Constraints
+		givenVersion      *semver.Version
+		err               error
+	)
+
+	compatibleVersion, err = semver.NewConstraint(compatibleNetboxVersion)
+	if err != nil {
+		panic(fmt.Sprintf("could not parse Netbox version constraint '%s'", compatibleNetboxVersion))
+	}
+
+	givenVersion, err = semver.NewVersion(version)
+	if err != nil {
+		panic(fmt.Sprintf("could not parse given Netbox version '%s'", version))
+	}
+
+	return compatibleVersion.Check(givenVersion)
+}