Add initial support for INI file merging (#349)

internal/mqini/mqini.go

@@ -19,7 +19,12 @@ package mqini
 
 import (
 	"bufio"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"github.com/ibm-messaging/mq-container/internal/command"
@@ -34,6 +39,12 @@ type QueueManager struct {
 	InstallationName string
 }
 
+var qmgrDir string
+
+var stanzasQMINI []string
+
+var stanzasMQATINI []string
+
 // getQueueManagerFromStanza parses a queue manager stanza
 func getQueueManagerFromStanza(stanza string) (*QueueManager, error) {
 	scanner := bufio.NewScanner(strings.NewReader(stanza))
@@ -76,3 +87,242 @@ func GetErrorLogDirectory(qm *QueueManager) string {
 	}
 	return filepath.Join(qm.Prefix, "qmgrs", qm.Directory, "errors")
 }
+
+//AddStanzas Reads supplied mq ini configuration files and updates the stanzas
+//into queue manager's ini configuration files.
+func AddStanzas(qmname string) error {
+
+	//find the qmgr directory.
+	qm, err := GetQueueManager(qmname)
+	if err != nil {
+		return err
+	}
+	qmgrDir = filepath.Join(qm.Prefix, "qmgrs", qm.Directory)
+
+	//Find the users ini configuration file
+	files := getIniFileList()
+	if len(files) > 1 {
+		msg := fmt.Sprintf("[ %v ]", files)
+		return errors.New("Only a single ini file can be provided. Following ini files are found:" + msg)
+	}
+	if len(files) == 0 {
+		//no ini file update required.
+		return nil
+	}
+
+	iniFileBytes, err := ioutil.ReadFile(files[0])
+	if err != nil {
+		return err
+	}
+	userconfig := string(iniFileBytes)
+	if len(userconfig) == 0 {
+		return nil
+	}
+
+	//Prepare a list of all supported stanzas
+	PopulateAllAvailableStanzas()
+
+	//Update the qmgr ini file with user config.
+	qmConfig, atConfig, err := PrepareConfigStanzasToWrite(userconfig)
+	if err != nil {
+		return err
+	}
+	err = writeConfigStanzas(qmConfig, atConfig)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// PopulateAllAvailableStanzas initializes the ini stanzas prescribed by mq specification.
+func PopulateAllAvailableStanzas() {
+	stanzasQMINI = []string{"ExitPath",
+		"Log",
+		"Service",
+		"ServiceComponent",
+		"Channels",
+		"TCP",
+		"ApiExitLocal",
+		"AccessMode",
+		"RestrictedMode",
+		"XAResourceManager",
+		"DefaultBindType",
+		"SSL",
+		"DiagnosticMessages",
+		"Filesystem",
+		"Security",
+		"TuningParameters",
+		"ExitPropertiesLocal",
+		"LU62",
+		"NETBIOS"}
+
+	stanzasMQATINI = []string{"AllActivityTrace", "ApplicationTrace"}
+}
+
+// getIniFileList Checks for the user supplied ini file in /etc/mqm directory.
+func getIniFileList() []string {
+
+	fileList := []string{}
+	filepath.Walk("/etc/mqm", func(path string, f os.FileInfo, err error) error {
+		if strings.HasSuffix(path, ".ini") {
+			fileList = append(fileList, path)
+		}
+		return nil
+	})
+	return fileList
+}
+
+//PrepareConfigStanzasToWrite Reads through the user supplied ini config file and prepares list of
+//updates to be written into corresponding mq ini files (qm.ini and/or mqat.ini files.)
+func PrepareConfigStanzasToWrite(userconfig string) (string, string, error) {
+
+	var qminiConfigStr string
+	var mqatiniConfigStr string
+
+	//read the initial version.
+	iniFileBytes, err := ioutil.ReadFile(filepath.Join(qmgrDir, "qm.ini"))
+	if err != nil {
+		return "", "", err
+	}
+	qminiConfigStr = string(iniFileBytes)
+
+	iniFileBytes, err = ioutil.ReadFile(filepath.Join(qmgrDir, "mqat.ini"))
+	if err != nil {
+		return "", "", err
+	}
+	mqatiniConfigStr = string(iniFileBytes)
+
+	stanzaListMerge := make(map[string]strings.Builder)
+	stanzaListAppend := make(map[string]strings.Builder)
+	var sbAppend strings.Builder
+	var sbMerger strings.Builder
+
+	scanner := bufio.NewScanner(strings.NewReader(userconfig))
+	scanner.Split(bufio.ScanLines)
+	consumetoAppend := false
+	consumeToMerge := false
+	var stanza string
+
+	//read through the user file and prepare what we want.
+	for scanner.Scan() {
+		if strings.Contains(scanner.Text(), ":") {
+			consumetoAppend = false
+			consumeToMerge = false
+			stanza = scanner.Text()
+			//check if this stanza exists in the qm.ini/mqat.ini files
+			if strings.Contains(qminiConfigStr, stanza) ||
+				(strings.Contains(mqatiniConfigStr, stanza) && !(strings.Contains(stanza, "ApplicationTrace"))) {
+				consumeToMerge = true
+				sbMerger = strings.Builder{}
+
+				stanzaListMerge[stanza] = sbMerger
+			} else {
+				consumetoAppend = true
+				sbAppend = strings.Builder{}
+				stanzaListAppend[stanza] = sbAppend
+			}
+		} else {
+			if consumetoAppend {
+				sb := stanzaListAppend[stanza]
+				sb.WriteString(scanner.Text() + "\n")
+				stanzaListAppend[stanza] = sb
+			}
+			if consumeToMerge {
+				sb := stanzaListMerge[stanza]
+				sb.WriteString(scanner.Text() + "\n")
+				stanzaListMerge[stanza] = sb
+			}
+		}
+	}
+
+	//merge if stanza exits.
+	if len(stanzaListMerge) > 0 {
+		for key := range stanzaListMerge {
+			toWrite, filename := ValidateStanzaToWrite(key)
+			if toWrite {
+				attrList := stanzaListMerge[key]
+				switch filename {
+				case "qm.ini":
+					qminiConfigStr = prepareStanzasToMerge(key, attrList, qminiConfigStr)
+				case "mqat.ini":
+					mqatiniConfigStr = prepareStanzasToMerge(key, attrList, mqatiniConfigStr)
+				default:
+				}
+			}
+		}
+	}
+
+	//append new stanzas.
+	if len(stanzaListAppend) > 0 {
+		for key := range stanzaListAppend {
+			attrList := stanzaListAppend[key]
+			if strings.Contains(strings.Join(stanzasMQATINI, ", "), strings.TrimSuffix(strings.TrimSpace(key), ":")) {
+				mqatiniConfigStr = prepareStanzasToAppend(key, attrList, mqatiniConfigStr)
+			} else {
+				qminiConfigStr = prepareStanzasToAppend(key, attrList, qminiConfigStr)
+			}
+		}
+	}
+
+	return qminiConfigStr, mqatiniConfigStr, nil
+}
+
+//ValidateStanzaToWrite Validates stanza to be written and the file it belongs to.
+func ValidateStanzaToWrite(stanza string) (bool, string) {
+	stanza = strings.TrimSpace(stanza)
+	if strings.Contains(stanza, ":") {
+		stanza = stanza[:len(stanza)-1]
+	}
+
+	if strings.Contains(strings.Join(stanzasQMINI, ", "), stanza) {
+		return true, "qm.ini"
+	} else if strings.Contains(strings.Join(stanzasMQATINI, ", "), stanza) {
+		return true, "mqat.ini"
+	} else {
+		return false, ""
+	}
+}
+
+//prepareStanzasToAppend Prepares list of stanzas that are to be appended into qm ini files(qm.ini/mqat.ini)
+func prepareStanzasToAppend(key string, attrList strings.Builder, iniConfig string) string {
+	newVal := key + "\n" + attrList.String()
+	iniConfig = iniConfig + newVal
+	return iniConfig
+}
+
+//prepareStanzasToMerge Prepares list of stanzas that are to be updated into qm ini files(qm.ini/mqat.ini)
+//These stanzas are already present in mq ini files and their values have to be updated with user supplied ini.
+func prepareStanzasToMerge(key string, attrList strings.Builder, iniConfig string) string {
+	lineScanner := bufio.NewScanner(strings.NewReader(attrList.String()))
+	lineScanner.Split(bufio.ScanLines)
+	for lineScanner.Scan() {
+		attrLine := lineScanner.Text()
+		keyvalue := strings.Split(attrLine, "=")
+		//this line present in qm.ini, update value.
+		if strings.Contains(iniConfig, keyvalue[0]) {
+			re := regexp.MustCompile(keyvalue[0] + "=.*")
+			iniConfig = re.ReplaceAllString(iniConfig, attrLine)
+		} else { //this line not present in qm.ini file, add it.
+			re := regexp.MustCompile(key)
+			newVal := key + "\n" + attrLine
+			iniConfig = re.ReplaceAllString(iniConfig, newVal)
+		}
+	}
+	return iniConfig
+}
+
+//writeConfigStanzas Writes the ini file updates into corresponding mq ini files.
+func writeConfigStanzas(qmConfig string, atConfig string) error {
+
+	err := ioutil.WriteFile(filepath.Join(qmgrDir, "qm.ini"), []byte(qmConfig), 0644)
+	if err != nil {
+		return err
+	}
+
+	err = ioutil.WriteFile(filepath.Join(qmgrDir, "mqat.ini"), []byte(atConfig), 0644)
+	if err != nil {
+		return err
+	}
+	return nil
+}