refactor(func): Remove unused functions

Remvoe the logging functions replaced by the new structured implementation.

.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>

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
@@ -31,7 +31,6 @@ else
   width=80
 fi
 
-### functions
 badParam() {
   if [ "$1" = "null" ]; then
     printf "\n%sERROR: '%s' cannot have a NULL (empty) value.\n" "$err" "$2"
@@ -47,65 +46,80 @@ badParam() {
   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"
+    writePlainTextLog "${message}" "err" "fail" "$2" "$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
+}
+
+# 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"
+}
+
 scriptExamples() {
   newline
   printf "Update Cloudflare DNS host A/AAAA records with current IP address.\n"
@@ -157,6 +171,10 @@ scriptHelp() {
   textBlock "Switch value. Output log to console (stdout) instead of a log file. Can be combined with --nc if desired."
   textBlockDefaults "(disabled: output to log file)"
   newline
+  textBlockSwitches "--log-journal"
+  textBlock "Switch value. Output a structured log entry to your journaling system instead of a log file. Implies --nc."
+  textBlockDefaults "(disabled: output to log file)"
+  newline
   textBlockSwitches "--no-log"
   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."
   textBlockDefaults "(disabled: output to log file)"
@@ -188,10 +206,6 @@ scriptHelp() {
   exit 0
 }
 
-stamp() {
-    (date +%F" "%T)
-}
-
 newline() {
   printf "\n"
 }
@@ -208,51 +222,11 @@ 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
 scriptPath="$(CDPATH='' \cd -- "$(dirname -- "$0")" && pwd -P)"
 scriptName="$(basename "$0")"
 logFile="$scriptPath/${scriptName%.*}.log"
+logToJournal=0
 accountFile="$scriptPath/cloudflare.credentials"
 colourizeLogFile=1
 dnsRecords=""
@@ -292,6 +266,10 @@ while [ $# -gt 0 ]; do
   # log to the console instead of a file
     logFile="/dev/stdout"
     ;;
+  --log-journal)
+  # log to the journal system instead of a file
+    logToJournal=1
+    ;;
   --no-log)
   # do not log anything
     logFile="/dev/null"
@@ -353,16 +331,26 @@ done
 ### pre-flight checks
 if ! command -v curl >/dev/null; then
   printf "\n%sThis script requires 'curl' be installed and accessible. Exiting.%s\n\n" "$err" "$norm"
+  writePlainTextLog "'curl' must be installed and accessible" "fatal" "fail" "preexec" 2
   exit 2
 fi
 if ! command -v jq >/dev/null; then
   printf "\n%sThis script requires 'jq' be installed and accessible. Exiting.%s\n\n" "$err" "$norm"
+  writePlainTextLog "'jq' must be installed and accessible" "fatal" "fail" "preexec" 2
   exit 2
 fi
-[ -z "$dnsRecords" ] && badParam errMsg "You must specify at least one DNS record to update. Exiting."
+if [ -z "$dnsRecords" ]; then
-# verify credentials file exists and is not empty (default check)
+  badParam errMsg "You must specify at least one DNS record to update. Exiting."
+  writePlainTextLog "At least one DNS record to update must be specified" "fatal" "fail" "params" 1
+fi
+# verify the credentials file exists and is not empty (default check)
 if [ ! -f "$accountFile" ] || [ ! -s "$accountFile" ]; then
-    badParam errMsg "Cannot find Cloudflare credentials file (${accountFile}). Exiting."
+  badParam errMsg "Cannot find the Cloudflare credentials file (${accountFile}). Exiting."
+  writePlainTextLog "Cannot find the specified Cloudflare credentials file (${accountFile})" "fatal" "fail" "params" 1
+fi
+if [ "$logToJournal" -eq 1 ] && ! command -v logger >/dev/null 2>&1; then
+  printf "\n%sThis script requires 'logger' be installed to write entries to your journaling system. Exiting.%s\n\n" "$err" "$norm"
+  exit 2
 fi
 # turn off log file colourization if parameter is set
 if [ "$colourizeLogFile" -eq 0 ]; then
@@ -377,74 +365,72 @@ if [ "$colourizeLogFile" -eq 0 ]; then
 fi
 
 ### initial log entries
-{
+writePlainTextLog "starting '${scriptName}'" "info" "ok" "script"
-    printf "%s[%s] -- Cloudflare DDNS update-script: starting --%s\n" "$ok" "$(stamp)" "$norm"
+writePlainTextLog "script path: ${scriptPath}/${scriptName}" "debug" "ok" "startup"
-    printf "Parameters:\n"
+writePlainTextLog "credentials file: ${accountFile}" "debug" "ok" "startup"
-    printf "script path: %s\n" "$scriptPath/$scriptName"
-    printf "credentials file: %s\n" "$accountFile"
 
-    if [ "$ip4" -eq 1 ]; then
+if [ "$ip4" -eq 1 ]; then
-        printf "mode: IP4\n"
+  writePlainTextLog "mode: IPv4" "debug" "ok" "startup"
-    elif [ "$ip6" -eq 1 ]; then
+elif [ "$ip6" -eq 1 ]; then
-        printf "mode: IP6\n"
+  writePlainTextLog "mode: IPv6" "debug" "ok" "startup"
-    fi
+fi
 
-    # detect and report IP address
+# detect and report IP address
-    if [ -z "$ipAddress" ]; then
+if [ -z "$ipAddress" ]; then
   # detect public ip address
   if [ "$ip4" -eq 1 ]; then
     if ! ipAddress="$(curl -s $ip4DetectionSvc)"; then
-                printf "ddns ip address:%s ERROR%s\n" "$err" "$norm"
+      writePlainTextLog \
-                exitError 10
+        "Unable to auto-detect this machine's public IP address; try again later or supply the IP address to be used" "err" "fail" "detectip" 10
+      exit 10
     fi
   fi
   if [ "$ip6" -eq 1 ]; then
     if ! ipAddress="$(curl -s $ip6DetectionSvc)"; then
-                printf "ddns ip address:%s ERROR%s\n" "$err" "$norm"
+      writePlainTextLog \
-                exitError 10
+        "Unable to auto-detect this machine's public IP address; try again later or supply the IP address to be used" "err" "fail" "detectip" 10
+      exit 10
     fi
   fi
-        printf "ddns ip address (detected): %s\n" "$ipAddress"
+  writePlainTextLog "DDNS IP address (detected): $ipAddress" "info" "ok" "startup"
-    else
+else
-        printf "ddns ip address (supplied): %s\n" "$ipAddress"
+  writePlainTextLog "DDNS IP address (supplied): $ipAddress" "info" "ok" "startup"
-    fi
+fi
 
-    # iterate DNS records to update
+# iterate DNS records to update
-    dnsRecordsToUpdate="$(printf '%s' "${dnsRecords}" | sed "s/${dnsSeparator}*$//")$dnsSeparator"
+dnsRecordsToUpdate="$(printf '%s' "${dnsRecords}" | sed "s/${dnsSeparator}*$//")$dnsSeparator"
-    while [ -n "$dnsRecordsToUpdate" ] && [ "$dnsRecordsToUpdate" != "$dnsSeparator" ]; do
+while [ -n "$dnsRecordsToUpdate" ] && [ "$dnsRecordsToUpdate" != "$dnsSeparator" ]; do
   record="${dnsRecordsToUpdate%%${dnsSeparator}*}"
   dnsRecordsToUpdate="${dnsRecordsToUpdate#*${dnsSeparator}}"
 
-        if [ -z "$record" ]; then continue; fi
+  if [ -z "$record" ]; then
-        printf "updating record: %s\n" "$record"
+    continue
-    done
+  fi
-
+  writePlainTextLog "DNS host record '${record}' queued for update" "info" "ok" "startup"
-    printf "(end of parameter list)\n"
+done
-} >>"$logFile"
 
 ### read Cloudflare credentials
-writeLog process "Reading Cloudflare credentials"
 case "$accountFile" in
 /*)
-    # absolute path, use as-is
+# absolute path, use as-is
-    # shellcheck source=./cloudflare.credentials
+# shellcheck source=./cloudflare.credentials
   . "$accountFile"
   ;;
 *)
-    # relative path, rewrite
+# relative path, rewrite
-    # shellcheck source=./cloudflare.credentials
+# shellcheck source=./cloudflare.credentials
   . "./$accountFile"
   ;;
 esac
 if [ -z "$cfKey" ]; then
-    writeLog process-error
+  writePlainTextLog "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
+  writePlainTextLog "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"
+writePlainTextLog "Cloudflare credentials file read successfully" "debug" "ok" "creds"
 
 ### connect to Cloudflare and do what needs to be done!
 dnsRecordsToUpdate="$dnsRecords$dnsSeparator"
@@ -459,70 +445,69 @@ 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 ${cfKey}" \
+      -H "Content-Type: application/json"
+  )"; then
+    writePlainTextLog "Unable to connect to Cloudflare servers; please try again later." "err" "fail" "cflogin" 3
+    exit 3
+  fi
+
+  # an API error on this GET request likely indicates an authentication error that would affect all remaining operations
+  # no reason to continue processing other dns records and pile-up errors which might look like a DoS attempt
   cfSuccess="$(printf "%s" "$cfLookup" | jq -r '.success')"
   if [ "$cfSuccess" = "false" ]; then
-        writeLog process-error
+    listCFErrors "$cfLookup" "cflogin"
-        listCFErrors "$cfLookup"
+    writePlainTextLog "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 [ "$resultCount" = "0" ]; then
-        # warn if record of host not found
+    writePlainTextLog "Cannot find an existing record matching '${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 = ${currentIpAddr}"
+  writePlainTextLog "The current IP address for '${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 ${record} is already up-to-date"
+    writePlainTextLog "The IP address for '${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
+    writePlainTextLog "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 [ "$cfSuccess" = "true" ]; then
-        writeLog process-done "DONE"
+    writePlainTextLog "The IP address for '${record}' successfully updated" "info" "ok" "ddns"
-        writeLog success "IP address for ${record} updated."
   else
-        writeLog process-error
+    listCFErrors "$cfResult" "ddns"
-        listCFErrors "$cfResult"
+    writePlainTextLog "Unable to update the IP address for '${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 +516,14 @@ done
 
 # exit
 if [ "$invalidDomainCount" -ne 0 ]; then
-    writeLog warning "${invalidDomainCount} invalid host(s) supplied for updating."
+  writePlainTextLog "${invalidDomainCount} invalid host(s) were supplied for updating" "warn" "warn" "ddns"
 fi
 if [ "$failedHostCount" -ne 0 ]; then
-    exitError 26
+  writePlainTextLog \
+    "${failedHostCount} host update(s) failed; review 'CF-ERR:' lines in this log to help determine what may have gone wrong" "err" "fail" "ddns" 26
+  exit 26
 else
-    exitOK
+  writePlainTextLog "${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