pg_dump-Dow

#!/usr/bin/env bash

help() { cat <<'END'

Synopsis:
	Midnight dump of PG database into backup/<database>/<database>.<Dow>.d
Description:
	Typical butt save, daily pg_dump of a PostgreSQL database.
	The backup format is pg_dump directory, named like:
	
		backup/<database>/<database>-<Dow>.d/

	Compression is 9 (best).  The parallel jobs is set to 4 processors. 
	Faults are written to run/pg_dump-midnight-<database>.fault
Usage:
	D=setspace
	0 0 * * * pg_dump-Dow $DB >>log/pg_dump-Dow-$DB.log 2>&1
Depends
	$JMSCOTT_ROOT/bin/duration-english
	$PGHOME/bin/pg_dump
Source Code:
	https://github.com/jmscott/work
Exit Status:
	0	dump ok
	1	dump failed
END
#
#  Note:
#	Investigate if directory format of pg_dump includes checksum in
#	manifest.
#
	exit 0
}

DOW=$(date +%a)
PROG=$(basename $0)
START_EPOCH=$(date +%s)
JOBS=4
COMPRESSION=9
PSQL='psql --no-psqlrc'

now()
{
	date +'%Y/%m/%d: %H:%M:%S'
}

log()
{
	echo "$(now): $@"
}

leave()
{
	STATUS=$?
	ELAPSED_DURATION=$(duration-english $(expr $(date +%s) - $START_EPOCH))
	log "elapsed: $ELAPSED_DURATION"
	log 'good bye, cruel world'
	exit $STATUS
}

die()
{
	MSG="ERROR: $@"
	test -w run && echo "$(now): $MSG" >>run/$PROG.fault
	log "$MSG" >&2
	exit 1
}

in_PATH()
{
	EXE=$1
	type -P $EXE 2>/dev/null || die "executable not in \$PATH: $EXE"
}

test "$1" = '--help' && help

test $# = 1 || die "wrong number of arguments: got $#, expected 1"
DATABASE=$1

log 'hello, world'
trap leave EXIT INT TERM

test -r etc/profile && . etc/profile

log "PATH=$PATH"
in_PATH duration-english
in_PATH pg_dump

log "PGHOME=$PGHOME"
log "PGHOST=$PGHOST"
log "PGPORT=$PGPORT"
log "PGUSER=$PGUSER"
log "PGPASSWORD=$PGPASSWORD"
export PGDATABASE=$DATABASE
log "PGDATABASE=$PGDATABASE"
log "day of week: $DOW"
log "compression: $COMPRESSION"

log "parallel jobs: $JOBS"

BACKUP=backup/$DATABASE
log "backup db dir: $BACKUP"
mkdir -p $BACKUP || die "mkdir backup failed: exit status=$?"
BACKUP=backup/$DATABASE/$DATABASE-$DOW.d
log "backup Dow dir: $BACKUP"

if [ -d $BACKUP ];  then
	log "removing previous backup: $(du -sh $BACKUP | awk '{print $1}')"
	rm -rf $BACKUP || die "rm daily backup dir failed: exit status=$?"
fi
DBSIZE=$($PSQL --tuples-only -c '
SELECT
	pg_size_pretty(pg_database_size(current_database()));
' | sed 's/^ *//')
log "size of raw database: $DATABASE: $DBSIZE"
log 'starting pg_dump ...'
pg_dump $DATABASE							\
	--format=d							\
	--jobs=$JOBS							\
	--file=$BACKUP							||
  die "pg_dump failed: exit status=$?"
log '... pg_dump done, OK, no errors'
log "dump size: $(du -sh $BACKUP | awk '{print $1}')"

exit 0