Inclusion of two patches written by [shamer] + modified config file management.

CHANGELOG

@@ -1,3 +1,12 @@
+0.6.1 (5 May 2012)
+=================
+Inclusion of two patches written by [shamer] + modified config file management.
+
+  * Added option to use ssmtp to send mail [shamer]
+  * Added lock file to prevent running multiple instances simultaneously [shamer]
+  * Modified config file management (no more specified on the command line, must be specified as an parameter at the beginning of the script)
+  * Fixed bad check_variables() behaviour when not using Amazon S3 storage backend without commenting AWS API keys
+
 0.6 Version Six (4 May 2012)
 ============================
 This is a rework of the script to include some github patches that were brought to the original script in order to make the script more generic than only Amazon S3 oriented and fix a few issues.

README

@@ -14,9 +14,9 @@ machine ever does go belly up.
 Optionally, you can set up an email address where the log file will be sent,
 which is useful when the script is used via cron.
 
-This version is a rewriting of the code originally written by Damon Timm, including many
+This version is a rewriting of the code originally written by Damon Timm,
-patches that have been brought to the original scripts by various forks
+including many patches that have been brought to the original scripts by
-on Github.
+various forks on Github.
 
 Latest version of the code available at:
 http://github.com/zertrin/duplicity-backup
@@ -51,6 +51,15 @@ REQUIREMENTS
 * s3cmd (optional)
 * mailx (optional)
 
+CONFIGURATION
+=============
+
+The configuration takes place directly in the script and is documented there.
+
+You can optionnaly specifiy a custom config file in the CONFIG parameter at the
+very beginning. Any parameter specified in this custom config file will
+override thoses specified in the script.
+
 COMMON USAGE EXAMPLES
 =====================
 

duplicity-backup.sh

@@ -27,6 +27,10 @@
 #
 # ---------------------------------------------------------------------------- #
 
+# Set config file (uncomment if you want to use a separate config file)
+# Its content override config below !
+#CONFIG="/some/path/to/config/file"
+
 # AMAZON S3 INFORMATION
 # Comment out this lines if you're not using S3
 AWS_ACCESS_KEY_ID="foobar_aws_key_id"
@@ -132,6 +136,10 @@ EMAIL_TO=
 EMAIL_FROM=
 EMAIL_SUBJECT=
 
+# command to use to send mail (uncomment to activate functionnality)
+#MAIL="mailx"
+#MAIL="ssmtp"
+
 # TROUBLESHOOTING: If you are having any problems running this script it is
 # helpful to see the command output that is being generated to determine if the
 # script is causing a problem or if it is an issue with duplicity (or your
@@ -144,21 +152,7 @@ EMAIL_SUBJECT=
 # Script Happens Below This Line - Shouldn't Require Editing #
 ##############################################################
 
-# Read config file
+# Read config file if specified
-CONFIG=
-while :
-do
-    case $1 in
-        -c | --config)
-            CONFIG=$2
-            shift 2
-            ;;
-        *)
-            break
-            ;;
-    esac
-done
-
 if [ ! -z "$CONFIG" -a -f "$CONFIG" ];
 then
   . $CONFIG
@@ -174,7 +168,10 @@ export PASSPHRASE
 LOGFILE="${LOGDIR}${LOG_FILE}"
 DUPLICITY="$(which duplicity)"
 S3CMD="$(which s3cmd)"
-MAIL="$(which mailx)"
+
+# File to use as a lock. The lock is used to insure that only one instance of
+# the script is running at a time.
+LOCKFILE=${LOGDIR}backup.lock
 
 if [ $ENCRYPTION = "yes" ]; then
   ENCRYPT="--encrypt-key=${GPG_KEY} --sign-key=${GPG_KEY}"
@@ -193,7 +190,10 @@ CONFIG_VAR_MSG="Oops!! ${0} was unable to run!\nWe are missing one or more impor
 if [ ! -x "$DUPLICITY" ]; then
   echo "ERROR: duplicity not installed, that's gotta happen first!" >&2
   exit 1
-elif  [ `echo ${DEST} | cut -c 1,2` = "s3" ]; then
+fi
+
+if  [ `echo ${DEST} | cut -c 1,2` = "s3" ]; then
+  DEST_IS_S3=true
   if [ ! -x "$S3CMD" ]; then
     echo $NO_S3CMD; S3CMD_AVAIL=false
   elif [ ! -f "${HOME}/.s3cfg" ]; then
@@ -201,9 +201,26 @@ elif  [ `echo ${DEST} | cut -c 1,2` = "s3" ]; then
   else
     S3CMD_AVAIL=true
   fi
+else
+  DEST_IS_S3=false
 fi
 
-if [ ! -d ${LOGDIR} ]; then
+check_variables ()
+{
+  if [[ ${ROOT} = "" || ${DEST} = "" || ${INCLIST} = "" || \
+         ${GPG_KEY} = "foobar_gpg_key" || \
+         ${PASSPHRASE} = "foobar_gpg_passphrase" || \
+         ${LOGDIR} = "/home/foobar_user_name/logs/test2/" || \
+         ( ${DEST_IS_S3} = true && ${AWS_ACCESS_KEY_ID} = "foobar_aws_key_id" ) || \
+         ( ${DEST_IS_S3} = true && ${AWS_SECRET_ACCESS_KEY} = "foobar_aws_access_key" ) ]]; then
+    echo -e ${CONFIG_VAR_MSG}
+    exit 1
+  fi
+}
+
+check_logdir()
+{
+  if [ ! -d ${LOGDIR} ]; then
     echo "Attempting to create log directory ${LOGDIR} ..."
     if ! mkdir -p ${LOGDIR}; then
       echo "Log directory ${LOGDIR} could not be created by this user: ${USER}"
@@ -212,11 +229,48 @@ if [ ! -d ${LOGDIR} ]; then
     else
       echo "Directory ${LOGDIR} successfully created."
     fi
-elif [ ! -w ${LOGDIR} ]; then
+  elif [ ! -w ${LOGDIR} ]; then
     echo "Log directory ${LOGDIR} is not writeable by this user: ${USER}"
     echo "Aborting..."
     exit 1
-fi
+  fi
+}
+
+email_logfile()
+{
+  if [ $EMAIL_TO ]; then
+      MAILCMD=$(which $MAIL)
+      if [ ! -x "$MAILCMD" ]; then
+          echo -e "Email couldn't be sent. ${MAIL} not available." >> ${LOGFILE}
+      else
+          EMAIL_SUBJECT=${EMAIL_SUBJECT:="duplicity-backup alert ${LOG_FILE}"}
+          if [ "$MAIL" = "ssmtp" ]; then
+            echo """Subject: ${EMAIL_SUBJECT}""" | cat - ${LOGFILE} | ${MAILCMD} -s ${EMAIL_TO}
+
+          elif ["$MAIL" = "mailx" ]; then
+            EMAIL_FROM=${EMAIL_FROM:+"-r ${EMAIL_FROM}"}
+            cat ${LOGFILE} | ${MAILCMD} -s """${EMAIL_SUBJECT}""" $EMAIL_FROM ${EMAIL_TO}
+          fi
+          echo -e "Email alert sent to ${EMAIL_TO} using ${MAIL}" >> ${LOGFILE}
+      fi
+  fi
+}
+
+get_lock()
+{
+  echo "Attempting to acquire lock ${LOCKFILE}" >> ${LOGFILE}
+  if ( set -o noclobber; echo "$$" > "${LOCKFILE}" ) 2> /dev/null; then
+      # The lock succeeded. Create a signal handler to remove the lock file when the process terminates.
+      trap 'EXITCODE=$?; echo "Removing lock. Exit code: ${EXITCODE}" >>${LOGFILE}; rm -f "${LOCKFILE}"' 0
+      echo "successfully acquired lock." >> ${LOGFILE}
+  else
+      # Write lock acquisition errors to log file and stderr
+      echo "lock failed, could not acquire ${LOCKFILE}" | tee -a ${LOGFILE} >&2
+      echo "lock held by $(cat ${LOCKFILE})" | tee -a ${LOGFILE} >&2
+      email_logfile
+      exit 2
+  fi
+}
 
 get_source_file_size()
 {
@@ -360,20 +414,12 @@ backup_this_script()
   echo -e "\nYou may want to write the above down and save it with the file."
 }
 
-check_variables ()
+check_variables
-{
+check_logdir
-  if [[ ${ROOT} = "" || ${DEST} = "" || ${INCLIST} = "" || \
-        ${AWS_ACCESS_KEY_ID} = "foobar_aws_key_id" || \
-        ${AWS_SECRET_ACCESS_KEY} = "foobar_aws_access_key" || \
-        ${GPG_KEY} = "foobar_gpg_key" || \
-        ${PASSPHRASE} = "foobar_gpg_passphrase" ]]; then
-    echo -e ${CONFIG_VAR_MSG}
-    echo -e ${CONFIG_VAR_MSG}"\n--------    END    --------" >> ${LOGFILE}
-    exit 1
-  fi
-}
 
-echo -e "--------    START duplicity-backup SCRIPT    --------\n" >> ${LOGFILE}
+echo -e "--------    START DUPLICITY-BACKUP SCRIPT    --------\n" >> ${LOGFILE}
+
+get_lock
 
 case "$1" in
   "--backup-script")
@@ -382,7 +428,6 @@ case "$1" in
   ;;
 
   "--full")
-    check_variables
     OPTION="full"
     include_exclude
     duplicity_backup
@@ -391,7 +436,6 @@ case "$1" in
   ;;
 
   "--verify")
-    check_variables
     OLDROOT=${ROOT}
     ROOT=${DEST}
     DEST=${OLDROOT}
@@ -411,7 +455,6 @@ case "$1" in
   ;;
 
   "--restore")
-    check_variables
     ROOT=$DEST
     OPTION="restore"
 
@@ -436,7 +479,6 @@ case "$1" in
   ;;
 
   "--restore-file")
-    check_variables
     ROOT=$DEST
     INCLUDE=
     EXCLUDE=
@@ -476,7 +518,6 @@ case "$1" in
   ;;
 
   "--list-current-files")
-    check_variables
     OPTION="list-current-files"
     ${DUPLICITY} ${OPTION} ${VERBOSITY} ${STATIC_OPTIONS} \
     $ENCRYPT \
@@ -485,7 +526,6 @@ case "$1" in
   ;;
 
   "--collection-status")
-    check_variables
     OPTION="collection-status"
     ${DUPLICITY} ${OPTION} ${VERBOSITY} ${STATIC_OPTIONS} \
     $ENCRYPT \
@@ -494,7 +534,6 @@ case "$1" in
   ;;
 
   "--backup")
-    check_variables
     include_exclude
     duplicity_backup
     duplicity_cleanup
@@ -504,7 +543,7 @@ case "$1" in
   *)
     echo -e "[Only show `basename $0` usage options]\n" >> ${LOGFILE}
     echo "  USAGE:
-      `basename $0` [-c configfile] [options]
+      `basename $0` [options]
 
     Options:
       --backup: runs an incremental backup
@@ -524,22 +563,14 @@ case "$1" in
       INCLIST (directories included)  = ${INCLIST[@]:0}
       EXCLIST (directories excluded)  = ${EXCLIST[@]:0}
       ROOT (root directory of backup) = ${ROOT}
+      LOGFILE (log file path)         = ${LOGFILE}
     "
   ;;
 esac
 
-echo -e "--------    END duplicity-backup SCRIPT    --------\n" >> ${LOGFILE}
+echo -e "--------    END DUPLICITY-BACKUP SCRIPT    --------\n" >> ${LOGFILE}
 
-if [ $EMAIL_TO ]; then
+email_logfile
-  if [ ! -x "$MAIL" ]; then
-    echo -e "Email couldn't be sent. mailx not available." >> ${LOGFILE}
-  else
-    EMAIL_FROM=${EMAIL_FROM:+"-r ${EMAIL_FROM}"}
-    EMAIL_SUBJECT=${EMAIL_SUBJECT:="duplicity-backup Alert ${LOG_FILE}"}
-    cat ${LOGFILE} | ${MAIL} -s """${EMAIL_SUBJECT}""" $EMAIL_FROM ${EMAIL_TO}
-    echo -e "Email alert sent to ${EMAIL_TO} using ${MAIL}" >> ${LOGFILE}
-  fi
-fi
 
 if [ ${ECHO} ]; then
   echo "TEST RUN ONLY: Check the logfile for command output."