"""postgresql backup plugin for backup system.

Data dumps are performed using 'pg_dump'
The following settings are read from the 'options'
heading in the backup.cfg file:
    pg_user : username to use for pg_dump
    pg_password : password for that user

By default, the options -d -C -E utf8 are used.
"""

import plugins, os

PIPE = plugins.subprocess.PIPE
Popen = plugins.subprocess.Popen

config = False
databases = []
BACKUP_PATH = '/var/backup/db/pgsql/'

def init(cfg, *args, **kwargs):
    global config, databases
    config = cfg
    databases = args
    print "config: %s, dbs: %s" % (config, databases)

def pre():
    """Prepare a copy of the postgres database using pg_dump."""
    # pg_dump -d -C -E utf8 django > django.psql
    # -E : encoding
    # -C : CREATE commands
    # -d : INSERT instead of COPY
    for db in databases:
        mkdir = "mkdir -p /tmp%s" % (BACKUP_PATH)
        dumpfile = "/tmp%s%s.psql" % (BACKUP_PATH, db)
        cmd = ['pg_dump', '-d', '-C', '-E', 'utf8', db]
        plugins.print_exec(mkdir)
        dumpfileObj = open(dumpfile, 'w')
        env = None
        opts = config.get_section("options")
        if hasattr(opts, "pg_password"):
            env={"PGPASSWORD": opts.pg_password}
        if hasattr(opts, "pg_user"):
            cmd.insert(1, '-U')
            cmd.insert(2, opts.pg_user)
        print ' '.join(cmd) + '(%r)' % env
        process = Popen(cmd, stdout=dumpfileObj,
                env=env).wait()

def run():
    """Backup all of the trac copies in /tmp.
    Read the rsync manpage in the 'relative' section to see why,
    but we want to run rsync with the source /tmp/./path/to/trac"""
    rsync = config.rsync()
    dest = config.destination()
    # we want rsync + source + dest
    def source(db):
        return '/tmp/.%s%s.psql ' % (BACKUP_PATH, db)
    for db in databases:
        c = rsync + source(db) + dest
        print 'rs>', c
        plugins.print_exec(c)

def post():
    """Remove the copies we prepared in the pre() step."""
    for db in databases:
        rm = "rm -f /tmp%s%s.psql" % (BACKUP_PATH, db)
        plugins.print_exec(rm)

    rmdir = "rm -rf /tmp/var"
    plugins.print_exec(rmdir)