Ubuntu Manpage: PGObject::Util::DBAdmin - PostgreSQL Database Management Facilities for PGObject

Provided by: libpgobject-util-dbadmin-perl_1.6.1-1_all

NAME

       PGObject::Util::DBAdmin - PostgreSQL Database Management Facilities for PGObject

VERSION

       version 1.6.1

SYNOPSIS

       This module provides an interface to the basic Postgres db manipulation utilities.

        my $db = PGObject::Util::DBAdmin->new(
           connect_data => {
              user     => 'postgres',
              password => 'mypassword',
              host     => 'localhost',
              port     => '5432',
              dbname   => 'mydb'
           }
        );

        my @dbnames = $db->list_dbs(); # like psql -l

        $db->create(); # createdb
        $db->run_file(file => 'sql/initial_schema.sql'); # psql -f

        my $filename = $db->backup(format => 'c'); # pg_dump -Fc

        my $db2 = PGObject::Util::DBAdmin->new($db->export, (dbname => 'otherdb'));

        my $db3 = PGObject::Util::DBAdmin->new(
           connect_data => {
              service     => 'zephyr',
              sslmode     => 'require',
              sslkey      => "$HOME/.postgresql/postgresql.key",
              sslcert     => "$HOME/.postgresql/postgresql.crt",
              sslpassword => 'your-sslpassword',
           }
        );

PROPERTIES

connect_data
Contains a hash with connection parameters; see the PostgreSQL documentation
<https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS> for
supported parameters.

The usual parameters are:

• user

• password

• dbname

• host

• port

Please note that the key "requiressl" is deprecated in favor of "sslmode" and isn't
supported.

username (deprecated)
The username used to authenticate with the PostgreSQL server.

password (deprecated)
The password used to authenticate with the PostgreSQL server.

host (deprecated)
In PostgreSQL, this can refer to the hostname or the absolute path to the directory where
the UNIX sockets are set up.

port (deprecated)
Default '5432'

dbname (deprecated)
The database name to create or connect to.

stderr
When applicable, the stderr output captured from any external commands (for example
createdb or pg_restore) run during the previous method call. See notes in "CAPTURING".

stdout
When applicable, the stdout output captured from any external commands (for example
createdb or pg_restore) run during the previous method call. See notes in "CAPTURING".

logger
Provides a reference to the logger associated with the current instance. The logger uses
"ref $self" as its category, eliminating the need to create new loggers when deriving from
this class.

If you want to override the logger-instantiation behaviour, please implement the
"_build_logger" builder method in your derived class.

GLOBAL VARIABLES

   %helper_paths
       This hash variable contains as its keys the names of the PostgreSQL helper executables
       "psql", "dropdb", "pg_dump", etc. The values contain the paths at which the executables to
       be run are located. The default values are the names of the executables only, allowing
       them to be looked up in $PATH.

       Modification of the values in this variable are the strict realm of applications.
       Libraries using this library should defer potential required modifications to the
       applications based upon them.

SUBROUTINES/METHODS

new
Creates a new db admin object for manipulating databases.

BUILDARGS
Compensates for the legacy invocation with the "username", "password", "host", "port" and
"dbname" parameters.

verify_helpers( [ helpers => [...]], [operations => [...]])
Verifies ability to execute (external) helper applications by method name (through the
"operations" argument) or by external helper name (through the "helpers" argument).
Returns a hash ref with each key being the name of a helper application (see "helpers"
below) with the values being a boolean indicating whether or not the helper can be
successfully executed.

Valid values in the array referenced by the "operations" parameter are "create",
"run_file", "backup", "backup_globals", "restore" and "drop"; the methods this module
implements with the help of external helper programs. (Other values may be passed, but
unsupported values aren't included in the return value.)

Valid values in the array referenced by the "helpers" parameter are the names of the
PostgreSQL helper programs "createdb", "dropdb", "pg_dump", "pg_dumpall", "pg_restore" and
"psql". (Other values may be passed, but unsupported values will not be included in the
return value.)

When no arguments are passed, all helpers will be tested.

Note: "verify_helpers" is a class method, meaning it wants to be called as
"PGObject::Util::DBAdmin-"verify_helpers()>.

export
Exports the database parameters as a list so it can be used to create another object.

connect($options)
Connects to the database using DBI and returns a database connection.

Connection options may be specified in the $options hashref.

server_version([$dbname])
Returns a version string (like 9.1.4) for PostgreSQL. Croaks on error.

When a database name is specified, uses that database to connect to, using the credentials
specified in the instance.

If no database name is specified, 'template1' is used.

list_dbs([$dbname])
Returns a list of db names.

When a database name is specified, uses that database to connect to, using the credentials
specified in the instance.

If no database name is specified, 'template1' is used.

create
Creates a new database.

Croaks on error, returns true on success.

Supported arguments:

copy_of
Creates the new database as a copy of the specified one (using it as a template).
Optional parameter. Default is to create a database without a template.

run_file
Run the specified file on the db.

After calling this method, STDOUT and STDERR output from the external utility which runs
the file on the database are available as properties $db->stdout and $db->stderr
respectively.

Croaks on error. Returns true on success.

Recognized arguments are:

file
Path to file to be run. This is a mandatory argument.

vars
A hash reference containing "psql"-variables to be passed to the script being
executed. Running:

$dbadmin->run_file(file => '/tmp/pg.sql', vars => { schema => 'xyz' });

Is equivalent to starting the file "/tmp/pg.sql" with the command

\set schema xyz

To undefine a variable, associate the variable name (hash key) with the value "undef".

stdout_log
Provided for legacy compatibility. Optional argument. The full path of a file to which
STDOUT from the external psql utility will be appended.

errlog
Provided for legacy compatibility. Optional argument. The full path of a file to which
STDERR from the external psql utility will be appended.

backup
Creates a database backup file.

After calling this method, STDOUT and STDERR output from the external utility which runs
the file on the database are available as properties $db->stdout and $db->stderr
respectively.

Unlinks the output file and croaks on error.

Returns the full path of the file containining the backup.

Accepted parameters:

format
The specified format, for example c for custom. Defaults to plain text.

file
Full path of the file to which the backup will be written. If the file does not exist,
one will be created with umask 0600. If the file exists, it will be overwritten, but
its permissions will not be changed.

If undefined, a file will be created using File::Temp having umask 0600.

tempdir
The directory in which to write the backup file. Optional parameter. Uses File::Temp
default if not defined. Ignored if file parameter is given.

compress
Optional parameter. Specifies the compression level to use and is passed to the
underlying pg_dump command. Default is no compression.

backup_globals
This creates a file containing a plain text dump of global (inter-db) objects, such as
users and tablespaces. It uses pg_dumpall to do this.

Being a plain text file, it can be restored using the run_file method.

Unlinks the output file and croaks on error.

Returns the full path of the file containining the backup.

Accepted parameters:

If undefined, a file will be created using File::Temp having umask 0600.

tempdir
The directory in which to write the backup file. Optional parameter. Uses File::Temp
default if not defined. Ignored if file parameter is given.

restore
Restores from a saved file. Must pass in the file name as a named argument.

After calling this method, STDOUT and STDERR output from the external restore utility are
available as properties $db->stdout and $db->stderr respectively.

Croaks on error. Returns true on success.

Recognized arguments are:

file
Path to file which will be restored to the database. Required.

format
The file format, for example c for custom. Defaults to plain text.

drop
Drops the database. This is not recoverable. Croaks on error, returns true on success.

is_ready
Drops the database. This is not recoverable. Croaks on error, returns true on success.

CAPTURING

       This module uses "Capture::Tiny" to run extenal commands and capture their output, which
       is made available through the "stderr" and "stdout" properties.

       This capturing does not work if Perl's standard "STDOUT" or "STDERR" filehandles have been
       localized. In this situation, the localized filehandles are captured, but external system
       calls are not affected by the localization, so their output is sent to the original
       filehandles and is not captured.

       See the "Capture::Tiny" documentation for more details.

AUTHOR

       Chris Travers, "<chris at efficito.com>"

BUGS

       Please report any bugs or feature requests to "bug-pgobject-util-dbadmin at rt.cpan.org",
       or through the web interface at
       <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=PGObject-Util-DBAdmin>.  I will be
       notified, and then you'll automatically be notified of progress on your bug as I make
       changes.

SUPPORT

       You can find documentation for this module with the perldoc command.

           perldoc PGObject::Util::DBAdmin

       You can also look for information at:

       •   RT: CPAN's request tracker (report bugs here)

           <http://rt.cpan.org/NoAuth/Bugs.html?Dist=PGObject-Util-DBAdmin>

       •   AnnoCPAN: Annotated CPAN documentation

           <http://annocpan.org/dist/PGObject-Util-DBAdmin>

       •   CPAN Ratings

           <http://cpanratings.perl.org/d/PGObject-Util-DBAdmin>

       •   Search CPAN

           <http://search.cpan.org/dist/PGObject-Util-DBAdmin/>

ACKNOWLEDGEMENTS

LICENSE AND COPYRIGHT

       Copyright 2014-2020 Chris Travers.

       This program is distributed under the (Revised) BSD License:
       <http://www.opensource.org/licenses/BSD-3-Clause>

       Redistribution and use in source and binary forms, with or without modification, are
       permitted provided that the following conditions are met:

       * Redistributions of source code must retain the above copyright notice, this list of
       conditions and the following disclaimer.

       * Redistributions in binary form must reproduce the above copyright notice, this list of
       conditions and the following disclaimer in the documentation and/or other materials
       provided with the distribution.

       * Neither the name of Chris Travers's Organization nor the names of its contributors may
       be used to endorse or promote products derived from this software without specific prior
       written permission.

       THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
       MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
       COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
       EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
       HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
       TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
       SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.