BUG/MAJOR: version-compare: fix comparison for minimum required and current program version (#56)

Fixed regex used to extract program version.
`version` arg was unused. Now, it is renamed as `minVer` and used in comparison.
Additional `compareVersion` func added to compare minVer with currVer.
Comparision with `strings.Compare` didn't worked for cases like `0.1.10 > 0.1.2`
and therefore it is removed.
Added unit test for `compareVersion` func.

Author: amelhusic

haproxy/haproxy_cmd/run.go

@@ -105,14 +105,15 @@ func Start(sd *lib.Shutdown, cfg Config) (*dataplane.Dataplane, error) {
 	return dataplaneClient, nil
 }
 
-// execAndCapture Launch Help from program path and Find Version
+// getVersion Launch Help from program path and Find Version
 // to capture the output and retrieve version information
-func execAndCapture(path string, re *regexp.Regexp) (string, error) {
+func getVersion(path string) (string, error) {
 	cmd := exec.Command(path, "-v")
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		return "", fmt.Errorf("Failed executing %s: %s", path, err.Error())
 	}
+	re := regexp.MustCompile("\\d+(\\.\\d+)+")
 	return string(re.Find(out)), nil
 }
 
@@ -121,22 +122,83 @@ func CheckEnvironment(dataplaneapiBin, haproxyBin string) error {
 	var err error
 	wg := &sync.WaitGroup{}
 	wg.Add(2)
-	ensureVersion := func(path, rx, version string) {
+	ensureVersion := func(path, minVer string) {
 		defer wg.Done()
-		r := regexp.MustCompile(rx)
-		v, e := execAndCapture(path, r)
+		currVer, e := getVersion(path)
 		if e != nil {
 			err = e
-		} else if strings.Compare(v, "1.2") < 0 {
-			err = fmt.Errorf("%s version must be > 1.2, but is: %s", path, v)
+		}
+		res, e := compareVersion(currVer, minVer)
+		if e != nil {
+			err = e
+		}
+		if res < 0 {
+			err = fmt.Errorf("%s version must be > %s, but is: %s", path, minVer, currVer)
 		}
 	}
-	go ensureVersion(haproxyBin, "^HA-Proxy version ([0-9]\\.[0-9]\\.[0-9])", "2.0")
-	go ensureVersion(dataplaneapiBin, "^HAProxy Data Plane API v([0-9]\\.[0-9]\\.[0-9])", "1.2")
+	go ensureVersion(haproxyBin, "2.0")
+	go ensureVersion(dataplaneapiBin, "1.2")
 
 	wg.Wait()
 	if err != nil {
 		return err
 	}
 	return nil
 }
+
+// compareVersion compares two semver versions.
+// If v1 > v2 returns 1, if v1 < v2 returns -1, if equal returns 0.
+// If major versions are not the same, returns -1.
+// If an error occurs, returns -1 and error.
+func compareVersion(v1, v2 string) (int, error) {
+	a := strings.Split(v1, ".")
+	b := strings.Split(v2, ".")
+
+	if len(a) < 2 {
+		return -1, fmt.Errorf("%s arg is not a version string", v1)
+	}
+	if len(b) < 2 {
+		return -1, fmt.Errorf("%s arg is not a version string", v2)
+	}
+
+	if len(a) != len(b) {
+		switch {
+		case len(a) > len(b):
+			for i := len(b); len(b) < len(a); i++ {
+				b = append(b, " ")
+			}
+			break
+		case len(a) < len(b):
+			for i := len(a); len(a) < len(b); i++ {
+				a = append(a, " ")
+			}
+			break
+		}
+	}
+
+	var res int
+
+	for i, s := range a {
+		var ai, bi int
+		fmt.Sscanf(s, "%d", &ai)
+		fmt.Sscanf(b[i], "%d", &bi)
+
+		if i == 0 {
+			//major versions should be the same
+			if ai != bi {
+				res = -1
+				break
+			}
+			continue
+		}
+		if ai > bi {
+			res = 1
+			break
+		}
+		if ai < bi {
+			res = -1
+			break
+		}
+	}
+	return res, nil
+}

haproxy/haproxy_cmd/run_test.go

@@ -0,0 +1,35 @@
+package haproxy_cmd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type version struct {
+	v1     string
+	v2     string
+	status int
+}
+
+func TestCompareVersion(t *testing.T) {
+	tests := []*version{
+		{status: 1, v1: "1.3", v2: "1.2"},
+		{status: 1, v1: "1.3.1", v2: "1.3"},
+		{status: 1, v1: "2.0.1", v2: "2.0"},
+		{status: 0, v1: "2.0", v2: "2.0"},
+		{status: 0, v1: "2.0.0", v2: "2.0"},
+		{status: 0, v1: "2.0", v2: "2.0.0"},
+		{status: -1, v1: "1.2", v2: "1.3"},
+		{status: -1, v1: "1.3", v2: "1.3.1"},
+		{status: -1, v1: "2.0", v2: "2.0.1"},
+		{status: -1, v1: "2", v2: "2.0.1"},
+		{status: -1, v1: "2.0", v2: "2"},
+		{status: -1, v1: "3.0", v2: "2.2.2"},
+		{status: -1, v1: "2.2", v2: "3.0"},
+	}
+	for _, test := range tests {
+		res, _ := compareVersion(test.v1, test.v2)
+		require.Equal(t, res, test.status)
+	}
+}