Do not lock exclusively when listing backups

[backmeupscotty.git] / backmeupscotty

diff --git a/backmeupscotty b/backmeupscotty
index e9bab430abb4c03726c44a4338255499d266a000..65e4d53310b732200dc2c67edcd941f7caaf2b31 100644 (file)
--- a/backmeupscotty
+++ b/backmeupscotty
@@ -1,83 +1,256 @@
 #!/bin/bash
 
 REMOTE_HOST=localhost
 #!/bin/bash
 
 REMOTE_HOST=localhost

-REMOTE_BASE=/tmp/backmeupscotty
+REMOTE_DIR=/tmp/backmeupscotty/test

 ARCHIVE_KEEPNBACKUPS=30
 ARCHIVE_KEEPNDAYS=30
 ARCHIVE_KEEPNBACKUPS=30
 ARCHIVE_KEEPNDAYS=30

+BACKUP_RUNEVERYNTHDAY=1
+BWLIMIT=500KiB
+BACKUP_FORCE=0

 
 

-if [ $(pidof -x $(basename $0) | wc -w) -gt 2 ]; then 
-    echo BACKMEUPSCOTTY: Another instance of $(basename $0) is already running! >&2
-    exit 1
-fi
+_ERROR_ENCOUNTERED=0

 
 

-while getopts ":q" opt; do
-    case $opt in
-       q)
-           exec > /dev/null
-           ;;
-    esac
-done
+function timestamp {
+    date +'[%y-%m-%d|%H:%M:%S]'
+}
+
+function scottyline {
+    echo $(timestamp) $@
+}
+
+function scottyinfo {
+    if [ $_ERROR_ENCOUNTERED -eq 0 ]; then
+        scottyline $@
+    else
+        scottyline $@ >&2
+    fi
+}
+
+function scottyerror {
+    scottyline $@ >&2
+    if [ $_ERROR_ENCOUNTERED -eq 0 ]; then
+        _ERROR_ENCOUNTERED=1
+        scottyline "Going into verbose mode after error encounter." >&2
+    fi
+}
+
+function ssh255 {
+    ssh $@
+    sshret=$?
+
+    if [ $sshret -eq 255 ]; then
+        scottyerror "SSH connection failed!"
+        exit 1
+    else
+        return $sshret
+    fi
+}

 
 function grepbackups {
 
 function grepbackups {

-    ssh $REMOTE_HOST "ls $REMOTE_BASE/$1" | grep -E '[0-9]+-[0-9]+'
+    ssh255 $REMOTE_HOST "ls $REMOTE_DIR" | grep -E '[0-9]+-[0-9]+'
+}
+
+function isIncomplete {
+    if ( ssh255 $REMOTE_HOST '[ -d '$REMOTE_DIR/incomplete' ]' ); then
+        return 0
+    else
+        return 1
+    fi
+}
+
+function isNthDay {
+    if [ $(( ( $(date +%s) / (60*60*24) ) % $BACKUP_RUNEVERYNTHDAY )) -eq 0 ];
+    then
+        return 0
+    else
+        return 1
+    fi
+}
+
+function latestTooOld {
+    for oldbackup in $(grepbackups); do
+        tstamp=$(echo $oldbackup | cut -d'-' -f1)
+
+        if [ $(( $(date +%s) - $tstamp )) -lt $(( ($BACKUP_RUNEVERYNTHDAY*24+12)*60*60 )) ]
+        then
+            return 1
+        fi
+    done
+
+    return 0

 }
 
 function scottysync {
     timestamp=$(date +%s)
 
 }
 
 function scottysync {
     timestamp=$(date +%s)
 

-    echo BACKMEUPSCOTTY: Syncing $1 to $REMOTE_HOST:$REMOTE_BASE/$2 @$timestamp
+    scottyinfo "Syncing $SYNC_SRC to $REMOTE_HOST:$REMOTE_DIR @$timestamp."

 
 

-    if [ ! -d "$1" ]; then
-       echo BACKMEUPSCOTTY: Source dir $1 does not exist. Not syncing! >&2
-       return 1
+    if [ ! -d "$SYNC_SRC" ]; then
+        scottyerror "Source dir $SYNC_SRC does not exist. Not syncing!"
+        return 1

     fi
 
     fi
 

-    if [ $(ls -A "$1" | wc -l) -eq 0 ]; then
-       echo BACKMEUPSCOTTY: Source dir $1 is empty. Not syncing! >&2
-       return 1
+    if [ $(ls -A "$SYNC_SRC" | wc -l) -eq 0 ]; then
+        scottyerror "Source dir $SYNC_SRC is empty. Not syncing!"
+        return 1

     fi
 
     fi
 

-    dir_current=$REMOTE_BASE/$2/current
-    dir_incomplete=$REMOTE_BASE/$2/incomplete
-    dir_timestamped=$REMOTE_BASE/$2/$timestamp-$(date -d @$timestamp +%Y%m%d%H%M%S)
+    dir_current=$REMOTE_DIR/current
+    dir_incomplete=$REMOTE_DIR/incomplete
+    dir_timestamped=$REMOTE_DIR/$timestamp-$(date -d @$timestamp +%Y%m%d%H%M%S)

 
 

-    if [ -z $3 ]; then
-       rsync_exclude=""
+    if [ -z $SYNC_EXC ]; then
+        rsync_exclude=""

     else
     else

-       rsync_exclude=$(eval echo --exclude={$3} | tr -d {})
+        rsync_exclude=$(eval echo --exclude={$SYNC_EXC} | tr -d {})

     fi
 
     fi
 

-    if (ssh $REMOTE_HOST '[ ! -d '$REMOTE_BASE/$2' ]'); then
-       echo BACKMEUPSCOTTY: Creating destination directory $REMOTE_HOST:$REMOTE_BASE/$2
-       ssh $REMOTE_HOST "mkdir $REMOTE_BASE/$2"
+    if (ssh255 $REMOTE_HOST '[ ! -d '$REMOTE_DIR' ]'); then
+        scottyinfo "Creating destination directory $REMOTE_HOST:$REMOTE_DIR."
+        ssh255 $REMOTE_HOST "mkdir $REMOTE_DIR"

     fi
 
     fi
 

-    if (ssh $REMOTE_HOST '[ -d '$REMOTE_BASE/$2/incomplete' ]'); then
-       echo BACKMEUPSCOTTY: Continuing old incomplete backup >&2
+    if isIncomplete; then
+        scottyerror "Continuing old incomplete backup."

     fi
 
     fi
 

-    echo BACKMEUPSCOTTY: Starting rsync
-    rsync -e ssh \
-       -v -aHAX --numeric-ids --delete --delete-excluded \
-       --link-dest=$dir_current \
-       $rsync_exclude \
-       $1/ $REMOTE_HOST:$dir_incomplete/
-    
+    scottyinfo "Starting rsync."
+    rsync -e ssh --bwlimit=$BWLIMIT \
+          -v -aHAX --numeric-ids --delete --delete-excluded \
+          --link-dest=$dir_current \
+          $rsync_exclude \
+          $SYNC_SRC/ $REMOTE_HOST:$dir_incomplete/
+

     if [ $? -eq 0 ]; then
     if [ $? -eq 0 ]; then

-       echo BACKMEUPSCOTTY: Timestamping completed backup and linking to current backup
-       ssh $REMOTE_HOST \
-           "mv $dir_incomplete $dir_timestamped && rm -f $dir_current && ln -s $dir_timestamped $dir_current"
+        scottyinfo "Timestamping completed backup and linking to current backup."
+        ssh255 $REMOTE_HOST \
+               "mv $dir_incomplete $dir_timestamped && rm -f $dir_current && \
+               ln -s $(basename $dir_timestamped) $dir_current"
+    else
+        scottyerror "Rsync failed."
+    fi
+
+    while [ $(grepbackups | wc -l) -gt $ARCHIVE_KEEPNBACKUPS ]; do
+        oldestbackup=$(grepbackups | head -1)
+        oldestbackuptstamp=$(echo $oldestbackup | cut -d'-' -f1)
+
+        if [ $oldestbackuptstamp -lt $(( $(date +%s) - $ARCHIVE_KEEPNDAYS*60*60*24 )) ]; then
+            scottyinfo "Removing old backup $oldestbackup."
+            ssh255 $REMOTE_HOST rm -r "$REMOTE_DIR/$oldestbackup"
+        else
+            break
+        fi
+    done
+}
+
+function deleteLock {
+    if ! rmdir /var/lock/$(basename $0); then
+        scottyerror "Could not delete lockfile /tmp/$(basename $0).lock!"

     fi
     fi

+}
+
+function cleanup_abort {
+    scottyerror "Caught exit signal! Cleaning up."
+
+    cleanup ABORT
+
+    if [ $(jobs -p) ]; then
+        scottyerror "TERMinating remaining child processes."
+        kill $(jobs -p)
+    fi
+
+    deleteLock
+
+    exit
+}
+
+function cleanup {
+    scottyinfo "No cleanup function was defined."
+}
+
+function prepare {
+    scottyinfo "No prepare function was defined."
+}
+
+function cleanup_normal {
+    cleanup
+    deleteLock
+}
+
+function printhelp {
+    cat <<EOF
+Usage: $(basename $0) [OPTION]...

 
 

-    while [ $(grepbackups $2 | wc -l) -gt $ARCHIVE_KEEPNBACKUPS ]; do
-       oldestbackup=$(grepbackups $2 | head -1)
-       oldestbackuptstamp=$(echo $oldestbackup | cut -d'-' -f1)
+Recognized options:
+  -q   Only output errors
+  -n   Run only on nth day
+  -f   Force backup
+  -l   List existing backups
+  -h   Print out this help
+EOF
+}
+
+function exclusiveLock {
+    if ! mkdir /var/lock/$(basename $0); then
+       scottyerror "Another instance of $(basename $0) is still running!"
+       exit 1
+    else
+       trap deleteLock EXIT
+    fi
+}

 
 

-       if [ $oldestbackuptstamp -lt $(( $(date +%s) - $ARCHIVE_KEEPNDAYS*60*60*24 )) ]; then
-           echo BACKMEUPSCOTTY: Removing old backup $oldestbackup
-           ssh $REMOTE_HOST rm -r "$REMOTE_BASE/$2/$oldestbackup"
-       else
-           break
-       fi
+function backmeupscotty {
+    while getopts "qn:flh" opt; do
+        case $opt in
+            q)
+                exec > /dev/null
+                ;;
+            n)
+                BACKUP_RUNEVERYNTHDAY=$OPTARG
+                ;;
+            f)
+                BACKUP_FORCE=1
+                ;;
+           l)
+               LIST_BACKUPS=1
+               ;;
+            h)
+                printhelp
+                exit 0
+                ;;
+        esac

     done
     done

+
+    ssh255 $REMOTE_HOST exit
+
+    if [ $LIST_BACKUPS ]; then
+       for backup in $(grepbackups); do
+           echo $backup
+       done
+       exit 0
+    fi
+
+    exclusiveLock
+
+    if [ $BACKUP_FORCE -eq 1 ]; then
+        scottyinfo "Backup was enforced."
+    elif latestTooOld; then
+        scottyerror "The latest backup is too old."
+    elif isNthDay; then
+        scottyinfo "This is the nth day."
+    else
+        scottyinfo "No backup has to be done. Exiting."
+        exit 0
+    fi
+
+    scottyinfo "Performing backup."
+
+    trap cleanup_abort EXIT
+
+    prepare
+    scottysync
+
+    trap cleanup_normal EXIT
+
+    exit 0

 }
 }