first commit

internal/mqversion/mqversion.go

@@ -0,0 +1,97 @@
+/*
+© Copyright IBM Corporation 2020
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package mqversion
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/ibm-messaging/mq-container/internal/command"
+)
+
+// Get will return the current MQ version
+func Get() (string, error) {
+	mqVersion, _, err := command.Run("dspmqver", "-b", "-f", "2")
+	if err != nil {
+		return "", fmt.Errorf("Error Getting MQ version: %v", err)
+	}
+	return strings.TrimSpace(mqVersion), nil
+}
+
+// Compare returns an integer comparing two MQ version strings lexicographically. The result will be 0 if currentVersion==checkVersion, -1 if currentVersion < checkVersion, and +1 if currentVersion > checkVersion
+func Compare(checkVersion string) (int, error) {
+	currentVersion, err := Get()
+	if err != nil {
+		return 0, err
+	}
+
+	currentVRMF, err := parseVRMF(currentVersion)
+	if err != nil {
+		return 0, err
+	}
+	compareVRMF, err := parseVRMF(checkVersion)
+	if err != nil {
+		return 0, fmt.Errorf("failed to parse compare version: %w", err)
+	}
+	return currentVRMF.compare(*compareVRMF), nil
+}
+
+type vrmf [4]int
+
+func (v vrmf) String() string {
+	return fmt.Sprintf("%d.%d.%d.%d", v[0], v[1], v[2], v[3])
+}
+
+func (v vrmf) compare(to vrmf) int {
+	for idx := 0; idx < 4; idx++ {
+		if v[idx] < to[idx] {
+			return -1
+		}
+		if v[idx] > to[idx] {
+			return 1
+		}
+	}
+	return 0
+}
+
+func parseVRMF(vrmfString string) (*vrmf, error) {
+	versionParts := strings.Split(vrmfString, ".")
+	if len(versionParts) != 4 {
+		return nil, fmt.Errorf("incorrect number of parts to version string: expected 4, got %d", len(versionParts))
+	}
+	vmrfPartNames := []string{"version", "release", "minor", "fix"}
+	parsed := vrmf{}
+	for idx, value := range versionParts {
+		partName := vmrfPartNames[idx]
+		if value == "" {
+			return nil, fmt.Errorf("empty %s found in VRMF", partName)
+		}
+		val, err := strconv.Atoi(value)
+		if err != nil {
+			return nil, fmt.Errorf("non-numeric %s found in VRMF", partName)
+		}
+		if val < 0 {
+			return nil, fmt.Errorf("negative %s found in VRMF", partName)
+		}
+		if idx == 0 && val == 0 {
+			return nil, fmt.Errorf("zero value for version not allowed")
+		}
+		parsed[idx] = val
+	}
+	return &parsed, nil
+}