refactor(log): Use CLEF for JSON logs

Use Compact Log Event Format (CLEF) for JSON logs along with custom properties.

.gitattributes

@@ -55,6 +55,23 @@
 *.bat      text eol=crlf
 *.cmd      text eol=crlf
 
+# web frontend stack -- force LF so SRI hashes are always correct
+*.html     text eol=lf
+*.htm      text eol=lf
+*.css      text eol=lf
+*.min.css  text eol=lf
+*.js       text eol=lf
+*.min.js   text eol=lf
+*.php      text eol=lf
+
+# Visual Studio projects (Rider also)
+*.cs     diff=csharp
+*.sln    merge=union
+*.csproj merge=union
+*.vbproj merge=union
+*.fsproj merge=union
+*.dbproj merge=union
+
 # Serialisation
 *.json     text
 *.toml     text
@@ -79,3 +96,5 @@
 .gitattributes  export-ignore
 .gitignore      export-ignore
 .gitkeep        export-ignore
+.idea           export-ignore
+.vscode         export-ignore

.gitignore

@@ -1 +1,35 @@
+#
+# JetBrains exclusions
+#
+
+riderModule.iml
+/_ReSharper.Caches/
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Generated files
+.idea/**/contentModel.xml
+.idea/**/GitCommitMessageStorage.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# modules
+.idea_modules/
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# project-specific exclusions
 *.log

.idea/developer-tools.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="DeveloperToolsToolWindowSettingsV1" lastSelectedContentNodeId="base64-encoder-decoder" pluginVersion="9.0.0">
+    <developerToolsConfigurations />
+  </component>
+</project>

.idea/git_toolbox_prj.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GitToolBoxProjectSettings">
+    <option name="commitMessageIssueKeyValidationOverride">
+      <BoolValueOverride>
+        <option name="enabled" value="true" />
+      </BoolValueOverride>
+    </option>
+    <option name="commitMessageValidationEnabledOverride">
+      <BoolValueOverride>
+        <option name="enabled" value="true" />
+      </BoolValueOverride>
+    </option>
+  </component>
+</project>

.idea/indexLayout.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="UserContentModel">
+    <attachedFolders />
+    <explicitIncludes />
+    <explicitExcludes />
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="com.itcodebox.notebooks.projectservice.ProjectUIState">
+    <option name="selectedNotebookId" value="1" />
+    <option name="selectedChapterId" value="1" />
+    <option name="selectedNoteId" value="1" />
+  </component>
+</project>

.idea/projectSettingsUpdater.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RiderProjectSettingsUpdater">
+    <option name="singleClickDiffPreview" value="1" />
+    <option name="unhandledExceptionsIgnoreList" value="1" />
+    <option name="vcsConfiguration" value="3" />
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

Folder.DotSettings

@@ -0,0 +1,4 @@
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=cfddns/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=mydomain/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=myserver/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

cfddns.sh

@@ -3,8 +3,8 @@
 #
 # update Cloudflare DNS records with current (dynamic) IP address
 #    Script by Asif Bacchus <asif@bacchus.cloud>
-#    Last modified: May 10, 2021
+#    Last modified: July 19, 2026
-#    Version 2.2
+#    Version 3.0
 #
 
 ### text formatting presets using tput
@@ -31,81 +31,137 @@ else
   width=80
 fi
 
-### functions
 badParam() {
   if [ "$1" = "null" ]; then
     printf "\n%sERROR: '%s' cannot have a NULL (empty) value.\n" "$err" "$2"
     printf "%sPlease use '--help' for assistance.%s\n\n" "$cyan" "$norm"
+    ([ "$logToConsole" -eq 0 ]) && writeLog \
+      "${2} cannot have a NULL (empty) value" "critical" "fail" "preexec" 1
     exit 1
   elif [ "$1" = "dne" ]; then
     printf "\n%sERROR: '%s %s'\n" "$err" "$2" "$3"
     printf "file or directory does not exist or is empty.%s\n\n" "$norm"
+    ([ "$logToConsole" -eq 0 ]) && writeLog \
+      "${3}: file or directory does not exist or is empty" "critical" "fail" "preexec" 1
     exit 1
   elif [ "$1" = "errMsg" ]; then
     printf "\n%sERROR: %s%s\n\n" "$err" "$2" "$norm"
+    ([ "$logToConsole" -eq 0 ]) && writeLog \
+      "${2%%\Exit*}" "fatal" "fail" "preexec" 1
     exit 1
   fi
 }
 
-exitError() {
+getHostname() {
-    case "$1" in
+  (hostname -s)
-    3)
-        errMsg="Unable to connect to Cloudflare servers. This is probably a temporary networking issue. Please try again later."
-        ;;
-    10)
-        errMsg="Unable to auto-detect IP address. Try again later or supply the IP address to be used."
-        ;;
-    20)
-        errMsg="Cloudflare authorized email address (cfEmail) is either null or undefined. Please check your Cloudflare credentials file."
-        ;;
-    21)
-        errMsg="Cloudflare authorized API key (cfKey) is either null or undefined. Please check your Cloudflare credentials file."
-        ;;
-    22)
-        errMsg="Cloudflare zone id (cfZoneId) is either null or undefined. Please check your Cloudflare credentials file."
-        ;;
-    25)
-        errMsg="Cloudflare API error. Please review any 'CF-ERR:' lines in this log for details."
-        ;;
-    26)
-        errMsg="${failedHostCount} host update(s) failed. Any 'CF-ERR:' lines noted in this log may help determine what went wrong."
-        ;;
-    *)
-        writeLog error "An unspecified error occurred. (code: 99)"
-        printf "%s[%s] -- Cloudflare DDNS update-script: completed with error(s) --%s\n" "$err" "$(stamp)" "$norm" >>"$logFile"
-        exit 99
-        ;;
-    esac
-    writeLog error "$errMsg" "$1"
-    printf "%s[%s] -- Cloudflare DDNS update-script: completed with error(s) --%s\n" "$err" "$(stamp)" "$norm" >>"$logFile"
-    exit "$1"
 }
 
-exitOK() {
+getTimeStamp() {
-    printf "%s[%s] -- Cloudflare DDNS update-script: completed successfully --%s\n" "$ok" "$(stamp)" "$norm" >>"$logFile"
+  (date -u +"%Y-%m-%dT%H:%M:%SZ")
-    exit 0
 }
 
+lowercase() {
+  echo "$1" | tr '[:upper:]' '[:lower:]'
+}
+
+uppercase() {
+  echo "$1" | tr '[:lower:]' '[:upper:]'
+}
+
+# 1: cloudflare error object, 2: operation identifier
 listCFErrors() {
   # extract error codes and messages in separate variables, replace newlines with underscores
   codes="$(printf "%s" "$1" | jq -r '.errors | .[] | .code' | tr '\n' '_')"
   messages="$(printf "%s" "$1" | jq -r '.errors | .[] | .message' | tr '\n' '_')"
 
-    # iterate codes and messages and assemble into coherent messages in log
+  # iterate codes and messages, assemble into a coherent log message
   while [ -n "$codes" ] && [ -n "$messages" ]; do
-        # get first code and message in respective sets
+    # get the first code and message in respective sets
     code="${codes%%_*}"
     message="${messages%%_*}"
 
-        # update codes and messages sets by removing first item in each set
+    # update sets of codes and messages by removing the first item (above) in each set
     codes="${codes#*_}"
     messages="${messages#*_}"
 
     # output to log
-        writeLog cf "$message" "$code"
+    writeLog "${message}" "err" "fail" "$2:CF-ERR" "$code"
   done
 }
 
+standardizeLogLevels() {
+  LEVEL_TO_STANDARDIZE="$(lowercase "$1")"
+  case "$LEVEL_TO_STANDARDIZE" in
+  "critical" | "crit" | "fatal")
+    echo "CRIT"
+    ;;
+  "error" | "err")
+    echo "ERR"
+    ;;
+  "warning" | "warn")
+    echo "WARN"
+    ;;
+  "information" | "info")
+    echo "INFO"
+    ;;
+  "debug" | "verbose")
+    echo "DEBUG"
+    ;;
+  *)
+    echo "INFO"
+    ;;
+  esac
+}
+
+# $1: message, $2: level, $3: status, [$4: operation], [$5: code]
+writeJsonLog() {
+  # not enough information to generate a meaningful log message
+  if [ -z "$1" ] || [ $# -lt 3 ]; then
+    return
+  fi
+
+  JSON_PROPS="$(
+    jq --null-input -c \
+      --arg timestamp "$(getTimeStamp)" \
+      --arg hostname "$(getHostname)" \
+      --arg pName "$LOG_PROGRAM_NAME" \
+      --arg pid "$$" \
+      --arg level "$(standardizeLogLevels "$2")" \
+      --arg status "$(uppercase "$3")" \
+      --arg message "$1" \
+      --arg operation "${4:-UNSPECIFIED}" \
+      --arg code "${5:-0}" \
+      '{"@t":$timestamp, "@m":$message, "@l":$level, "hostname":$hostname, "programName":$pName, "pid":$pid, "status":$status, "operation":$operation, "code":$code}' \
+  )"
+
+  printf "%s\n" "$JSON_PROPS" >>"$logFile"
+  return
+}
+
+# modified syslog fmt: <ISO-8601 timestamp> <hostname> <tag>[pid]: [LEVEL:$2] [STATUS:$3] <MESSAGE:$1> (<OPERATION:$4>:<CODE:$5>)
+writePlainTextLog() {
+  # not enough information to generate a meaningful log message
+  if [ -z "$1" ] || [ $# -lt 3 ]; then
+    return
+  fi
+
+  printf "%s %s %s[%s]: [%s] [%s] %s (%s:%s)\n" \
+    "$(getTimeStamp)" "$(getHostname)" "$LOG_PROGRAM_NAME" "$$" \
+    "$(standardizeLogLevels "$2")" "$(uppercase "$3")" "$1" "${4:-UNSPECIFIED}" "${5:-0}" \
+    >>"$logFile"
+}
+
+writeLog() {
+  ([ "$logToNone" -eq 1 ]) && return
+
+  PT_LOG_LEVEL="$(standardizeLogLevels "$2")"
+  ([ "$logDebug" -eq 0 ] && [ "$PT_LOG_LEVEL" = "DEBUG" ]) && return
+
+  ([ "$logToJournal" -eq 1 ]) && return # TODO: replace this with function when implemented
+  ([ "$useJsonLogFmt" -eq 1 ]) && writeJsonLog "$@"
+  ([ "$useSyslogLogFmt" -eq 1 ]) && writePlainTextLog "$@"
+}
+
 scriptExamples() {
   newline
   printf "Update Cloudflare DNS host A/AAAA records with current IP address.\n"
@@ -139,30 +195,42 @@ scriptHelp() {
   textBlock "The only required parameter is '--records' which is a comma-delimited list of hostnames to update. However, there are several other options which may be useful to implement."
   textBlock "Parameters are listed below and followed by a description of their effect. If a default value exists, it will be listed on the following line in (parentheses)."
   newline
-    textBlock "${magenta}--- script related parameters ---${norm}"
+  textBlock "${magenta}--- script-related parameters ---${norm}"
   newline
   textBlockSwitches "-c | --cred | --creds | --credentials | -f (deprecated, backward-compatibility)"
-    textBlock "Path to file containing your Cloudflare *token* credentials. Please refer to the repo README for more information on format, etc."
+  textBlock "Path to the file containing your Cloudflare *token* credentials. Please refer to the repo README for more information on format, etc."
   textBlockDefaults "(${accountFile})"
   newline
-    textBlockSwitches "-l | --log"
+  textBlockSwitches "--log-file"
-    textBlock "Path where the log file should be written."
+  textBlock "Path where the log file should be written. Script will use file-based logging."
   textBlockDefaults "(${logFile})"
   newline
-    textBlockSwitches "--nc | --no-color | --no-colour"
-    textBlock "Switch value. Disables ANSI colours in the log. Useful if you review the logs using a reader that does not parse ANSI colour codes."
-    textBlockDefaults "(disabled: print logs in colour)"
-    newline
   textBlockSwitches "--log-console"
-    textBlock "Switch value. Output log to console (stdout) instead of a log file. Can be combined with --nc if desired."
+  textBlock "Switch value. Script will use console-based (stdout) logging."
-    textBlockDefaults "(disabled: output to log file)"
+  textBlockDefaults "(disabled: use file-based logging)"
   newline
-    textBlockSwitches "--no-log"
+  textBlockSwitches "--log-journal"
-    textBlock "Switch value. Do not create a log (i.e. no console, no file). You will not have *any* output from the script if you choose this option, so you will not know if updates succeeded or failed."
+  textBlock "Switch value. Script will use journald-based logging."
-    textBlockDefaults "(disabled: output to log file)"
+  textBlockDefaults "(disabled: use file-based logging)"
+  newline
+  textBlockSwitches "--log-none"
+  textBlock "Switch value. Script will not log anything. You will not have *any* output from the script if you choose this option, so you will not know if updates succeed or fail."
+  textBlockDefaults "(disabled: use file-based logging)"
+  newline
+  textBlockSwitches "--log-debug"
+  textBlock "Switch value. Log 'debug' level messages. This should normally remain disabled."
+  textBlockDefaults "(disabled: do not log 'debug' messages)"
+  newline
+  textBlockSwitches "--fmt-json"
+  textBlock "Switch value. Use JSON formatted key-value pair structured logging format. Best when using a log parsing tool or log management system to read your log files. Does not apply when using '--log-journal'."
+  textBlockDefaults "(enabled)"
+  newline
+  textBlockSwitches "--fmt-syslog"
+  textBlock "Switch value. Use a modified syslog (plain-text) format for log messages. Ideal when logging to the console. Does not apply when using '--log-journal'."
+  textBlockDefaults "(disabled: use structured JSON logging)"
   newline
   textBlockSwitches "-h | --help | -?"
-    textBlock "Display this help screen."
+  textBlock "Display this information screen."
   newline
   textBlockSwitches "--examples"
   textBlock "Show some usage examples."
@@ -173,7 +241,7 @@ scriptHelp() {
   textBlock "Comma-delimited list of hostnames for which IP addresses should be updated in Cloudflare DNS. This parameter is REQUIRED. Note that this script will only *update* records, it will not create new ones. If you supply hostnames that are not already defined in DNS, the script will log a warning and will skip those hostnames."
   newline
   textBlockSwitches "-i | --ip | --ip-address | -a | --address"
-    textBlock "New IP address for DNS host records. If you omit this, the script will attempt to auto-detect your public IP address and use that."
+  textBlock "New IP address for DNS host records. If you omit this, the script will attempt to auto-detect your public IP address and use that. N.B. IP addresses are *not* parsed for correctness."
   newline
   textBlockSwitches "-4 | --ip4 | --ipv4"
   textBlock "Switch value. Update Host 'A' records (IP4) only. Note that this script can only update either A *or* AAAA records. If you need to update both, you'll have to run the script once in IP4 mode and again in IP6 mode. If you specify both this switch and the IP6 switch, the last one specified will take effect."
@@ -188,10 +256,6 @@ scriptHelp() {
   exit 0
 }
 
-stamp() {
-    (date +%F" "%T)
-}
-
 newline() {
   printf "\n"
 }
@@ -208,60 +272,25 @@ textBlockSwitches() {
   printf "%s%s%s\n" "$cyan" "$1" "$norm"
 }
 
-writeLog() {
-    case "$1" in
-    cf)
-        printf "[%s] CF-ERR: %s (code: %s)\n" "$(stamp)" "$2" "$3" >>"$logFile"
-        ;;
-    err)
-        printf "%s[%s] ERR: %s%s\n" "$err" "$(stamp)" "$2" "$norm" >>"$logFile"
-        ;;
-    error)
-        printf "%s[%s] ERROR: %s (code: %s)%s\n" "$err" "$(stamp)" "$2" "$3" "$norm" >>"$logFile"
-        ;;
-    process)
-        printf "%s[%s] %s... %s" "$cyan" "$(stamp)" "$2" "$norm" >>"$logFile"
-        ;;
-    process-done)
-        printf "%s%s%s\n" "$cyan" "$2" "$norm" >>"$logFile"
-        ;;
-    process-error)
-        printf "%sERROR%s\n" "$err" "$norm" >>"$logFile"
-        ;;
-    process-warning)
-        printf "%s%s%s\n" "$warn" "$2" "$norm" >>"$logFile"
-        ;;
-    stamped)
-        printf "[%s] %s\n" "$(stamp)" "$2" >>"$logFile"
-        ;;
-    success)
-        printf "%s[%s] SUCCESS: %s%s\n" "$ok" "$(stamp)" "$2" "$norm" >>"$logFile"
-        ;;
-    warn)
-        printf "%s[%s] WARN: %s%s\n" "$warn" "$(stamp)" "$2" "$norm" >>"$logFile"
-        ;;
-    warning)
-        printf "%s[%s] WARNING: %s%s\n" "$warn" "$(stamp)" "$2" "$norm" >>"$logFile"
-        ;;
-    *)
-        printf "%s\n" "$2" >>"$logFile"
-        ;;
-    esac
-}
-
 ### default variable values
+LOG_PROGRAM_NAME="CFDDNS"
 scriptPath="$(CDPATH='' \cd -- "$(dirname -- "$0")" && pwd -P)"
 scriptName="$(basename "$0")"
 logFile="$scriptPath/${scriptName%.*}.log"
+logToJournal=0
+logToConsole=0
+logToNone=0
+logDebug=0
+useJsonLogFmt=1
+useSyslogLogFmt=0
 accountFile="$scriptPath/cloudflare.credentials"
-colourizeLogFile=1
 dnsRecords=""
 dnsSeparator=","
 ipAddress=""
 ip4=1
 ip6=0
-ip4DetectionSvc="http://ipv4.icanhazip.com"
+ip4DetectionSvc="https://ipv4.icanhazip.com"
-ip6DetectionSvc="http://ipv6.icanhazip.com"
+ip6DetectionSvc="https://ipv6.icanhazip.com"
 invalidDomainCount=0
 failedHostCount=0
 
@@ -279,8 +308,8 @@ while [ $# -gt 0 ]; do
   # display sample commands
     scriptExamples
     ;;
-    -l | --log)
+  --log-file)
-        # set log file location
+  # use file-based logging at the specified location
     if [ -n "$2" ]; then
       logFile="${2%/}"
       shift
@@ -289,19 +318,35 @@ while [ $# -gt 0 ]; do
     fi
     ;;
   --log-console)
-        # log to the console instead of a file
+  # use console-based logging
     logFile="/dev/stdout"
+    logToConsole=1
     ;;
-    --no-log)
+  --log-journal)
+  # use journald-based logging
+    logToJournal=1
+    ;;
+  --log-none)
   # do not log anything
     logFile="/dev/null"
+    logToNone=1
     ;;
-    --nc | --no-color | --no-colour)
+  --log-debug)
-        # do not colourize log file
+  # log debugging messages
-        colourizeLogFile=0
+    logDebug=1
+    ;;
+  --fmt-json)
+  # use JSON log formatting
+    useJsonLogFmt=1
+    useSyslogLogFmt=0
+    ;;
+  --fmt-syslog)
+  # use modified syslog plain-text log formatting
+    useSyslogLogFmt=1
+    useJsonLogFmt=0
     ;;
   -c | --cred* | -f)
-        # path to Cloudflare credentials file
+  # path to the Cloudflare credentials file
     if [ -n "$2" ]; then
       if [ -f "$2" ] && [ -s "$2" ]; then
         accountFile="${2%/}"
@@ -344,6 +389,8 @@ while [ $# -gt 0 ]; do
   *)
     printf "\n%sUnknown option: %s\n" "$err" "$1"
     printf "%sUse '--help' for valid options.%s\n\n" "$cyan" "$norm"
+    ([ "$logToConsole" -eq 0 ]) && writeLog \
+      "Unknown script parameter: '${1}'" "critical" "fail" "preexec" 1
     exit 1
     ;;
   esac
@@ -352,41 +399,36 @@ done
 
 ### pre-flight checks
 if ! command -v curl >/dev/null; then
-    printf "\n%sThis script requires 'curl' be installed and accessible. Exiting.%s\n\n" "$err" "$norm"
+  printf "\n%sThis script requires that 'curl' is installed and accessible. Exiting.%s\n\n" "$err" "$norm"
+  ([ "$logToConsole" -eq 0 ]) && writeLog "'curl' must be installed and accessible" "fatal" "fail" "preexec" 2
   exit 2
 fi
 if ! command -v jq >/dev/null; then
-    printf "\n%sThis script requires 'jq' be installed and accessible. Exiting.%s\n\n" "$err" "$norm"
+  printf "\n%sThis script requires that 'jq' is installed and accessible. Exiting.%s\n\n" "$err" "$norm"
+  ([ "$logToConsole" -eq 0 ]) && writeLog "'jq' must be installed and accessible" "fatal" "fail" "preexec" 2
   exit 2
 fi
-[ -z "$dnsRecords" ] && badParam errMsg "You must specify at least one DNS record to update. Exiting."
+if [ -z "$dnsRecords" ]; then
-# verify credentials file exists and is not empty (default check)
+  badParam errMsg "You must specify at least one DNS record to update. Exiting."
-if [ ! -f "$accountFile" ] || [ ! -s "$accountFile" ]; then
-    badParam errMsg "Cannot find Cloudflare credentials file (${accountFile}). Exiting."
 fi
-# turn off log file colourization if parameter is set
+# verify the credentials file exists and is not empty (default check)
-if [ "$colourizeLogFile" -eq 0 ]; then
+if [ ! -f "$accountFile" ] || [ ! -s "$accountFile" ]; then
-    bold=""
+  badParam errMsg "Cannot find the Cloudflare credentials file (${accountFile}) or it is empty. Exiting."
-    cyan=""
+fi
-    err=""
+if [ "$logToJournal" -eq 1 ] && ! command -v logger >/dev/null 2>&1; then
-    magenta=""
+  printf "\n%sThis script requires that 'logger' is installed to write journald entries. Exiting.%s\n\n" "$err" "$norm"
-    norm=""
+  exit 2
-    ok=""
-    warn=""
-    yellow=""
 fi
 
 ### initial log entries
-{
+writeLog "starting '${scriptName}'" "info" "ok" "script"
-    printf "%s[%s] -- Cloudflare DDNS update-script: starting --%s\n" "$ok" "$(stamp)" "$norm"
+writeLog "script path: ${scriptPath}/${scriptName}" "debug" "ok" "startup"
-    printf "Parameters:\n"
+writeLog "credentials file: ${accountFile}" "debug" "ok" "startup"
-    printf "script path: %s\n" "$scriptPath/$scriptName"
-    printf "credentials file: %s\n" "$accountFile"
 
 if [ "$ip4" -eq 1 ]; then
-        printf "mode: IP4\n"
+  writeLog "mode: IPv4" "debug" "ok" "startup"
 elif [ "$ip6" -eq 1 ]; then
-        printf "mode: IP6\n"
+  writeLog "mode: IPv6" "debug" "ok" "startup"
 fi
 
 # detect and report IP address
@@ -394,19 +436,21 @@ fi
   # detect public ip address
   if [ "$ip4" -eq 1 ]; then
     if ! ipAddress="$(curl -s $ip4DetectionSvc)"; then
-                printf "ddns ip address:%s ERROR%s\n" "$err" "$norm"
+      writeLog \
-                exitError 10
+        "Unable to auto-detect this machine's public IP address; try again later or supply the IP address to be used" "err" "fail" "detectip" 10
+      exit 10
     fi
   fi
   if [ "$ip6" -eq 1 ]; then
     if ! ipAddress="$(curl -s $ip6DetectionSvc)"; then
-                printf "ddns ip address:%s ERROR%s\n" "$err" "$norm"
+      writeLog \
-                exitError 10
+        "Unable to auto-detect this machine's public IP address; try again later or supply the IP address to be used" "err" "fail" "detectip" 10
+      exit 10
     fi
   fi
-        printf "ddns ip address (detected): %s\n" "$ipAddress"
+  writeLog "DDNS IP address (detected): $ipAddress" "info" "ok" "startup"
 else
-        printf "ddns ip address (supplied): %s\n" "$ipAddress"
+  writeLog "DDNS IP address (supplied): $ipAddress" "info" "ok" "startup"
 fi
 
 # iterate DNS records to update
@@ -415,15 +459,13 @@ fi
   record="${dnsRecordsToUpdate%%${dnsSeparator}*}"
   dnsRecordsToUpdate="${dnsRecordsToUpdate#*${dnsSeparator}}"
 
-        if [ -z "$record" ]; then continue; fi
+  if [ -z "$record" ]; then
-        printf "updating record: %s\n" "$record"
+    continue
+  fi
+  writeLog "DNS host record '${record}' queued for update" "info" "ok" "startup"
 done
 
-    printf "(end of parameter list)\n"
-} >>"$logFile"
-
 ### read Cloudflare credentials
-writeLog process "Reading Cloudflare credentials"
 case "$accountFile" in
 /*)
 # absolute path, use as-is
@@ -437,14 +479,14 @@ case "$accountFile" in
   ;;
 esac
 if [ -z "$cfKey" ]; then
-    writeLog process-error
+  writeLog "Cloudflare authorized API key (cfKey) is either null or undefined; please check your Cloudflare credentials file" "err" "fail" "creds" 21
-    exitError 21
+  exit 21
 fi
 if [ -z "$cfZoneId" ]; then
-    writeLog process-error
+  writeLog "Cloudflare zone id (cfZoneId) is either null or undefined; please check your Cloudflare credentials file" "err" "fail" "creds" 22
-    exitError 22
+  exit 22
 fi
-writeLog process-done "DONE"
+writeLog "Cloudflare credentials file read successfully" "debug" "ok" "creds"
 
 ### connect to Cloudflare and do what needs to be done!
 dnsRecordsToUpdate="$dnsRecords$dnsSeparator"
@@ -459,70 +501,69 @@ while [ -n "$dnsRecordsToUpdate" ] && [ "$dnsRecordsToUpdate" != "$dnsSeparator"
   record="${dnsRecordsToUpdate%%${dnsSeparator}*}"
   dnsRecordsToUpdate="${dnsRecordsToUpdate#*${dnsSeparator}}"
 
-    if [ -z "$record" ]; then continue; fi
+  if [ -z "$record" ]; then
-    writeLog process "Processing ${record}"
+    continue
-
-    # exit if curl/network error
-    if ! cfLookup="$(curl -s -X GET "https://api.cloudflare.com/client/v4/zones/${cfZoneId}/dns_records?name=${record}&type=${recordType}" \
-        -H "Authorization: Bearer ${cfKey}" \
-        -H "Content-Type: application/json")"; then
-        writeLog process-error
-        exitError 3
   fi
 
-    # exit if API error
+  # exit if curl/network error
-    # exit here since API errors on GET request probably indicates authentication error which would affect all remaining operations
+  if ! cfLookup="$(
-    # no reason to continue processing other hosts and pile-up errors which might look like a DoS attempt
+    curl -s -X GET "https://api.cloudflare.com/client/v4/zones/${cfZoneId}/dns_records?name=${record}&type=${recordType}" \
+      -H "Authorization: Bearer ${cfKey}" \
+      -H "Content-Type: application/json"
+  )"; then
+    writeLog "Unable to connect to Cloudflare servers; please try again later." "err" "fail" "cflogin" 3
+    exit 3
+  fi
+
+  # an API error on this GET request likely indicates an authentication error that would affect all remaining operations
+  # no reason to continue processing other dns records and pile-up errors which might look like a DoS attempt
   cfSuccess="$(printf "%s" "$cfLookup" | jq -r '.success')"
   if [ "$cfSuccess" = "false" ]; then
-        writeLog process-error
+    listCFErrors "$cfLookup" "cflogin"
-        listCFErrors "$cfLookup"
+    writeLog "Cloudflare API error; review any previously logged 'CF-ERR:' lines for details." "err" "fail" "cflogin" 25
-        exitError 25
+    exit 25
   fi
 
   resultCount="$(printf "%s" "$cfLookup" | jq '.result_info.count')"
 
-    # skip to next host if cannot find existing host record (this script *updates* only, does not create!)
+  # skip to the next host if an existing host record cannot be found (this script *updates* only, does not create!)
   if [ "$resultCount" = "0" ]; then
-        # warn if record of host not found
+    writeLog "Cannot find an existing record matching '${record}' to update" "warn" "warn" "ddns"
-        writeLog process-warning "NOT FOUND"
-        writeLog warn "Cannot find existing record to update for DNS entry: ${record}"
     invalidDomainCount=$((invalidDomainCount + 1))
     continue
   fi
 
   objectId=$(printf "%s" "$cfLookup" | jq -r '.result | .[] | .id')
   currentIpAddr=$(printf "%s" "$cfLookup" | jq -r '.result | .[] | .content')
-    writeLog process-done "FOUND: IP = ${currentIpAddr}"
+  writeLog "The current IP address for '${record}' is ${currentIpAddr}" "debug" "ok" "ddns"
 
-    # skip to next hostname if record already up-to-date
+  # skip to next hostname if record already up to date
   if [ "$currentIpAddr" = "$ipAddress" ]; then
-        writeLog stamped "IP address for ${record} is already up-to-date"
+    writeLog "The IP address for '${record}' is already up to date" "info" "ok" "ddns"
     continue
   fi
 
   # update record
-    writeLog process "Updating IP address for ${record}"
   updateJSON="$(jq -n --arg key0 content --arg value0 "${ipAddress}" '{($key0):$value0}')"
 
   # exit if curl/network error
-    if ! cfResult="$(curl -s -X PATCH "https://api.cloudflare.com/client/v4/zones/${cfZoneId}/dns_records/${objectId}" \
+  if ! cfResult="$(
+    curl -s -X PATCH "https://api.cloudflare.com/client/v4/zones/${cfZoneId}/dns_records/${objectId}" \
       -H "Authorization: Bearer ${cfKey}" \
       -H "Content-Type: application/json" \
-        --data "${updateJSON}")"; then
+      --data "${updateJSON}"
-        writeLog process-error
+  )"; then
-        exitError 3
+    writeLog "Unable to connect to Cloudflare servers; please try again later." "err" "fail" "ddns" 3
+    exit 3
   fi
 
   # note update success or failure
   cfSuccess="$(printf "%s" "$cfResult" | jq '.success')"
   if [ "$cfSuccess" = "true" ]; then
-        writeLog process-done "DONE"
+    writeLog "The IP address for '${record}' successfully updated" "info" "ok" "ddns"
-        writeLog success "IP address for ${record} updated."
   else
-        writeLog process-error
+    listCFErrors "$cfResult" "ddns"
-        listCFErrors "$cfResult"
+    writeLog "Unable to update the IP address for '${record}'" "err" "fail" "ddns"
-        writeLog err "Unable to update IP address for ${record}"
     # do not exit with error, API error here is probably an update issue specific to this host
     # increment counter and note it after all processing finished
     failedHostCount=$((failedHostCount + 1))
@@ -531,12 +572,14 @@ done
 
 # exit
 if [ "$invalidDomainCount" -ne 0 ]; then
-    writeLog warning "${invalidDomainCount} invalid host(s) supplied for updating."
+  writeLog "${invalidDomainCount} invalid host(s) were supplied for updating" "warn" "warn" "ddns"
 fi
 if [ "$failedHostCount" -ne 0 ]; then
-    exitError 26
+  writeLog \
+    "${failedHostCount} host update(s) failed; review 'CF-ERR:' lines in this log to help determine what may have gone wrong" "err" "fail" "ddns" 26
+  exit 26
 else
-    exitOK
+  writeLog "${scriptName} completed successfully" "info" "ok" "script"
 fi
 
 ### exit return codes

logger.sh

@@ -0,0 +1,161 @@
+#!/bin/sh
+
+getTimeStamp() {
+  (date -u +"%Y-%m-%dT%H:%M:%SZ")
+}
+
+getHostname() {
+  (hostname -s)
+}
+
+lowercase() {
+  echo "$1" | tr '[:upper:]' '[:lower:]'
+}
+
+uppercase() {
+  echo "$1" | tr '[:lower:]' '[:upper:]'
+}
+
+standardizeLogLevels() {
+  LEVEL_TO_STANDARDIZE="$(lowercase "$1")"
+  case "$LEVEL_TO_STANDARDIZE" in
+  "critical" | "crit" | "fatal")
+    echo "CRIT"
+    ;;
+  "error" | "err")
+    echo "ERR"
+    ;;
+  "warning" | "warn")
+    echo "WARN"
+    ;;
+  "information" | "info")
+    echo "INFO"
+    ;;
+  "debug" | "verbose")
+    echo "DEBUG"
+    ;;
+  *)
+    echo "INFO"
+    ;;
+  esac
+}
+
+translateLogLevelsToJournalD() {
+  LEVEL_TO_TRANSLATE="$(standardizeLogLevels "$1")"
+  case "$LEVEL_TO_TRANSLATE" in
+  "CRIT")
+    echo 2
+    ;;
+  "ERR")
+    echo 3
+    ;;
+  "WARN")
+    echo 4
+    ;;
+  "INFO")
+    echo 6
+    ;;
+  "DEBUG")
+    echo 7
+    ;;
+  *)
+    echo 6
+  esac
+}
+
+# modified syslog fmt: <ISO-8601 timestamp> <hostname> <tag>[pid]: [LEVEL:$2] [STATUS:$3] <MESSAGE:$1> (<OPERATION:$4>:<CODE:$5>)
+writePlainTextLog() {
+  # not enough information to generate a meaningful log message
+  if [ -z "$1" ] || [ $# -lt 3 ]; then
+    return
+  fi
+
+  printf "%s %s %s[%s]: [%s] [%s] %s (%s:%s)\n" \
+    "$(getTimeStamp)" "$(getHostname)" "$LOG_PROGRAM_NAME" "$$" \
+    "$(standardizeLogLevels "$2")" "$(uppercase "$3")" "$1" "${4:-UNSPECIFIED}" "${5:-999}"
+}
+
+# $1: message, $2: level, $3: status, [$4: operation], [$5: code]
+writeJsonLog() {
+  # not enough information to generate a meaningful log message
+  if [ -z "$1" ] || [ $# -lt 3 ]; then
+    return
+  fi
+
+  PROPS="$(
+    jq --null-input \
+      --arg timestamp "$(getTimeStamp)" \
+      --arg hostname "$(getHostname)" \
+      --arg pName "$LOG_PROGRAM_NAME" \
+      --arg pid "$$" \
+      --arg level "$(standardizeLogLevels "$2")" \
+      --arg status "$(uppercase "$3")" \
+      --arg message "$1" \
+      --arg operation "${4:-UNSPECIFIED}" \
+      --arg code "${5:-999}" \
+      '{"timestamp":$timestamp, "hostname":$hostname, "programName":$pName, "pid":$pid, "level":$level, "status":$status, "message":$message, "operation":$operation, "code":$code}' \
+  )"
+
+  echo "$PROPS" | jq "."
+  return
+}
+
+# $1: message, $2: level, $3: status, $4: operation, $5: code
+writeJournalDLog() {
+  # not enough information to generate a meaningful log message
+  if [ -z "$1" ] || [ $# -lt 3 ]; then
+    return
+  fi
+
+  J_TIMESTAMP="$(getTimeStamp)"
+  J_PID="$$"
+  J_PRIO="$(translateLogLevelsToJournalD "$2")"
+  J_STAT="$(uppercase "$3")"
+
+  logger --journald <<end
+SYSLOG_TIMESTAMP=${J_TIMESTAMP}
+SYSLOG_FACILITY=3
+SYSLOG_IDENTIFIER=${LOG_PROGRAM_NAME}
+SYSLOG_PID=${J_PID}
+PRIORITY=${J_PRIO}
+STATUS=${J_STAT}
+MESSAGE=$1
+OPERATION=${4:-UNSPECIFIED}
+ERRNO=${5:-999}
+end
+
+  return
+}
+
+LOG_PROGRAM_NAME="cfddns"
+
+if [ "$1" = "text" ]; then
+  writePlainTextLog # this will do nothing
+  writePlainTextLog "Testing plain-text logging output" # this will also do nothing
+  writePlainTextLog "Informational plain-text log message" "information" "ok" # info message
+  writePlainTextLog "Plain-text message forced to info level" "whoops" "ok" # level translated to default
+  writePlainTextLog "Warning! This is plain-text." "warning" "flagged" # warning level with 'flagged' status
+  writePlainTextLog "Error sample! This is plain-text." "err" "error" # error level message
+  writePlainTextLog "Unable to continue, critical failure. (This is plain-text)" "fatal" "exit" "startup" "2" # critical level error with operation and error code
+elif [ "$1" = "json" ]; then
+  writeJsonLog # this will do nothing
+  writeJsonLog "This is a test message" # this will also do nothing
+  writeJsonLog "Informational JSON log message" "information" "ok" # info message
+  writeJsonLog "JSON message forced to info level" "whoops" "ok" # level translated to default
+  writeJsonLog "Warning! This is JSON." "warning" "flagged" # warning level with 'flagged' status
+  writeJsonLog "Error sample! This is JSON." "err" "error" # error level message
+  writeJsonLog "Unable to continue, critical failure. (This is JSON)" "fatal" "exit" "startup" "2" # critical level error with operation and error code
+elif [ "$1" = "journal" ]; then
+  writeJournalDLog # this will do nothing
+  writeJournalDLog "This is a test message" # this will also do nothing
+  writeJournalDLog "Informational JOURNALD log message" "information" "ok" # info message
+  writeJournalDLog "JOURNALD message forced to info level" "whoops" "ok" # level translated to default
+  writeJournalDLog "Warning! This is a JOURNALD message." "warning" "flagged" # warning level with 'flagged' status
+  writeJournalDLog "Error sample! This is a JOURNALD." "err" "error" # error level message
+  writeJournalDLog "Unable to continue, critical failure. (This is JOURNALD message)" "fatal" "exit" "startup" "2" # critical level error with operation and error code
+else
+  printf "\nPlease specify either 'text', 'json', or 'journal' after the script name. Exiting.\n\n"
+  exit 1
+fi
+
+exit 0