"""
This module provides the functionality to create the temporal
SQL database and to establish a connection to the database.
Usage:
.. code-block:: python
>>> import grass.temporal as tgis
>>> # Create the temporal database
>>> tgis.init()
>>> # Establish a database connection
>>> dbif, connection_state_changed = tgis.init_dbif(None)
>>> dbif.connect()
>>> # Execute a SQL statement
>>> dbif.execute_transaction("SELECT datetime(0, 'unixepoch', 'localtime');")
>>> # Mogrify an SQL statement
>>> dbif.mogrify_sql_statement(
... ["SELECT name from raster_base where name = ?", ("precipitation",)]
... )
"SELECT name from raster_base where name = 'precipitation'"
>>> dbif.close()
(C) 2011-2014 by the GRASS Development Team
This program is free software under the GNU General Public
License (>=v2). Read the file COPYING that comes with GRASS
for details.
:author: Soeren Gebbert
"""
# import traceback
import os
import grass.script as gscript
from .c_libraries_interface import CLibrariesInterface
from grass.pygrass import messages
from grass.script.utils import decode
# Import all supported database backends
# Ignore import errors since they are checked later
try:
import sqlite3
except ImportError:
pass
# Postgresql is optional, existence is checked when needed
try:
import psycopg2
import psycopg2.extras
except:
pass
import atexit
from datetime import datetime
###############################################################################
[docs]def profile_function(func):
"""Profiling function provided by the temporal framework"""
do_profiling = os.getenv("GRASS_TGIS_PROFILE")
if do_profiling == "True" or do_profiling == "1":
import cProfile
import pstats
import io
pr = cProfile.Profile()
pr.enable()
func()
pr.disable()
s = io.StringIO()
sortby = "cumulative"
ps = pstats.Stats(pr, stream=s).sort_stats(sortby)
ps.print_stats()
print(s.getvalue())
else:
func()
# Global variable that defines the backend
# of the temporal GIS
# It can either be "sqlite" or "pg"
tgis_backend = None
[docs]def get_tgis_backend():
"""Return the temporal GIS backend as string
:returns: either "sqlite" or "pg"
"""
global tgis_backend
return tgis_backend
# Global variable that defines the database string
# of the temporal GIS
tgis_database = None
[docs]def get_tgis_database():
"""Return the temporal database string specified with t.connect"""
global tgis_database
return tgis_database
# The version of the temporal framework
# this value must be an integer larger than 0
# Increase this value in case of backward incompatible changes in the TGIS API
tgis_version = 2
# The version of the temporal database since framework and database version
# can differ this value must be an integer larger than 0
# Increase this value in case of backward incompatible changes
# temporal database SQL layout
tgis_db_version = 3
# We need to know the parameter style of the database backend
tgis_dbmi_paramstyle = None
[docs]def get_tgis_dbmi_paramstyle():
"""Return the temporal database backend parameter style
:returns: "qmark" or ""
"""
global tgis_dbmi_paramstyle
return tgis_dbmi_paramstyle
# We need to access the current mapset quite often in the framework, so we make
# a global variable that will be initiated when init() is called
current_mapset = None
current_location = None
current_gisdbase = None
###############################################################################
[docs]def get_current_mapset():
"""Return the current mapset
This is the fastest way to receive the current mapset.
The current mapset is set by init() and stored in a global variable.
This function provides access to this global variable.
"""
global current_mapset
return current_mapset
###############################################################################
[docs]def get_current_location():
"""Return the current location
This is the fastest way to receive the current location.
The current location is set by init() and stored in a global variable.
This function provides access to this global variable.
"""
global current_location
return current_location
###############################################################################
[docs]def get_current_gisdbase():
"""Return the current gis database (gisdbase)
This is the fastest way to receive the current gisdbase.
The current gisdbase is set by init() and stored in a global variable.
This function provides access to this global variable.
"""
global current_gisdbase
return current_gisdbase
###############################################################################
# If this global variable is set True, then maps can only be registered in
# space time datasets with the same mapset. In addition, only maps in the
# current mapset can be inserted, updated or deleted from the temporal database.
# Overwrite this global variable by: g.gisenv set="TGIS_DISABLE_MAPSET_CHECK=True"
# ATTENTION: Be aware to face corrupted temporal database in case this global
# variable is set to False. This feature is highly
# experimental and violates the grass permission guidance.
enable_mapset_check = True
# If this global variable is set True, the timestamps of maps will be written
# as textfiles for each map that will be inserted or updated in the temporal
# database using the C-library timestamp interface.
# Overwrite this global variable by: g.gisenv set="TGIS_DISABLE_TIMESTAMP_WRITE=True"
# ATTENTION: Be aware to face corrupted temporal database in case this global
# variable is set to False. This feature is highly
# experimental and violates the grass permission guidance.
enable_timestamp_write = True
[docs]def get_enable_mapset_check():
"""Return True if the mapsets should be checked while insert, update,
delete requests and space time dataset registration.
If this global variable is set True, then maps can only be registered
in space time datasets with the same mapset. In addition, only maps in
the current mapset can be inserted, updated or deleted from the temporal
database.
Overwrite this global variable by: g.gisenv set="TGIS_DISABLE_MAPSET_CHECK=True"
..warning::
Be aware to face corrupted temporal database in case this
global variable is set to False. This feature is highly
experimental and violates the grass permission guidance.
"""
global enable_mapset_check
return enable_mapset_check
[docs]def get_enable_timestamp_write():
"""Return True if the map timestamps should be written to the spatial
database metadata as well.
If this global variable is set True, the timestamps of maps will be
written as textfiles for each map that will be inserted or updated in
the temporal database using the C-library timestamp interface.
Overwrite this global variable by: g.gisenv set="TGIS_DISABLE_TIMESTAMP_WRITE=True"
..warning::
Be aware that C-libraries can not access timestamp information if
they are not written as spatial database metadata, hence modules
that make use of timestamps using the C-library interface will not
work with maps that were created without writing the timestamps.
"""
global enable_timestamp_write
return enable_timestamp_write
###############################################################################
# The global variable that stores the PyGRASS Messenger object that
# provides a fast and exit safe interface to the C-library message functions
message_interface = None
def _init_tgis_message_interface(raise_on_error=False):
"""Initiate the global message interface
:param raise_on_error: If True raise a FatalError exception in case of
a fatal error, call sys.exit(1) otherwise
"""
global message_interface
if message_interface is None:
message_interface = messages.get_msgr(raise_on_error=raise_on_error)
[docs]def get_tgis_message_interface():
"""Return the temporal GIS message interface which is of type
grass.pygrass.message.Messenger()
Use this message interface to print messages to stderr using the
GRASS C-library messaging system.
"""
global message_interface
return message_interface
###############################################################################
# The global variable that stores the C-library interface object that
# provides a fast and exit safe interface to the C-library libgis,
# libraster, libraster3d and libvector functions
c_library_interface = None
def _init_tgis_c_library_interface():
"""Set the global C-library interface variable that
provides a fast and exit safe interface to the C-library libgis,
libraster, libraster3d and libvector functions
"""
global c_library_interface
if c_library_interface is None:
c_library_interface = CLibrariesInterface()
[docs]def get_tgis_c_library_interface():
"""Return the C-library interface that
provides a fast and exit safe interface to the C-library libgis,
libraster, libraster3d and libvector functions
"""
global c_library_interface
return c_library_interface
###############################################################################
# Set this variable True to raise a FatalError exception
# in case a fatal error occurs using the messenger interface
raise_on_error = False
[docs]def set_raise_on_error(raise_exp=True):
"""Define behavior on fatal error, invoked using the tgis messenger
interface (msgr.fatal())
The messenger interface will be restarted using the new error policy
:param raise_exp: True to raise a FatalError exception instead of calling
sys.exit(1) when using the tgis messenger interface
.. code-block:: python
>>> import grass.temporal as tgis
>>> tgis.init()
>>> ignore = tgis.set_raise_on_error(False)
>>> msgr = tgis.get_tgis_message_interface()
>>> tgis.get_raise_on_error()
False
>>> msgr.fatal("Ohh no no no!")
Traceback (most recent call last):
File "__init__.py", line 239, in fatal
sys.exit(1)
SystemExit: 1
>>> tgis.set_raise_on_error(True)
False
>>> msgr.fatal("Ohh no no no!")
Traceback (most recent call last):
File "__init__.py", line 241, in fatal
raise FatalError(message)
FatalError: Ohh no no no!
:returns: current status
"""
global raise_on_error
tmp_raise = raise_on_error
raise_on_error = raise_exp
global message_interface
if message_interface:
message_interface.set_raise_on_error(raise_on_error)
else:
_init_tgis_message_interface(raise_on_error)
return tmp_raise
[docs]def get_raise_on_error():
"""Return True if a FatalError exception is raised instead of calling
sys.exit(1) in case a fatal error was invoked with msgr.fatal()
"""
global raise_on_error
return raise_on_error
###############################################################################
[docs]def get_tgis_version():
"""Get the supported version of the temporal framework
:returns: The version number of the temporal framework as integer
"""
global tgis_version
return tgis_version
###############################################################################
[docs]def get_tgis_db_version():
"""Get the supported version of the temporal database
:returns: The version number of the temporal database as integer
"""
global tgis_db_version
return tgis_db_version
###############################################################################
###############################################################################
# The temporal database string set with t.connect
# with substituted GRASS variables gisdbase, location and mapset
tgis_database_string = None
[docs]def get_tgis_database_string():
"""Return the preprocessed temporal database string
This string is the temporal database string set with t.connect
that was processed to substitute location, gisdbase and mapset
variables.
"""
global tgis_database_string
return tgis_database_string
###############################################################################
[docs]def get_sql_template_path():
base = os.getenv("GISBASE")
base_etc = os.path.join(base, "etc")
return os.path.join(base_etc, "sql")
###############################################################################
[docs]def stop_subprocesses():
"""Stop the messenger and C-interface subprocesses
that are started by tgis.init()
"""
global message_interface
global c_library_interface
if message_interface:
message_interface.stop()
if c_library_interface:
c_library_interface.stop()
# We register this function to be called at exit
atexit.register(stop_subprocesses)
[docs]def get_available_temporal_mapsets():
"""Return a list of of mapset names with temporal database driver and names
that are accessible from the current mapset.
:returns: A dictionary, mapset names are keys, the tuple (driver,
database) are the values
"""
global c_library_interface
global message_interface
mapsets = c_library_interface.available_mapsets()
tgis_mapsets = {}
for mapset in mapsets:
mapset = mapset
driver = c_library_interface.get_driver_name(mapset)
database = c_library_interface.get_database_name(mapset)
message_interface.debug(
1,
"get_available_temporal_mapsets: "
"\n mapset %s\n driver %s\n database %s" % (mapset, driver, database),
)
if driver and database:
# Check if the temporal sqlite database exists
# We need to set non-existing databases in case the mapset is the current
# mapset
# to create it
if (
driver == "sqlite" and os.path.exists(database)
) or mapset == get_current_mapset():
tgis_mapsets[mapset] = (driver, database)
# We need to warn if the connection is defined but the database does not
# exists
if driver == "sqlite" and not os.path.exists(database):
message_interface.warning(
"Temporal database connection defined as:\n"
+ database
+ "\nBut database file does not exist."
)
return tgis_mapsets
###############################################################################
[docs]def init(raise_fatal_error=False, skip_db_version_check=False):
"""This function set the correct database backend from GRASS environmental
variables and creates the grass temporal database structure for raster,
vector and raster3d maps as well as for the space-time datasets strds,
str3ds and stvds in case it does not exist.
Several global variables are initiated and the messenger and C-library
interface subprocesses are spawned.
Re-run this function in case the following GRASS variables change while
the process runs:
- MAPSET
- LOCATION_NAME
- GISDBASE
- TGIS_DISABLE_MAPSET_CHECK
- TGIS_DISABLE_TIMESTAMP_WRITE
Re-run this function if the following t.connect variables change while
the process runs:
- temporal GIS driver (set by t.connect driver=)
- temporal GIS database (set by t.connect database=)
The following environmental variables are checked:
- GRASS_TGIS_PROFILE (True, False, 1, 0)
- GRASS_TGIS_RAISE_ON_ERROR (True, False, 1, 0)
..warning::
This functions must be called before any spatio-temporal processing
can be started
:param raise_fatal_error: Set this True to assure that the init()
function does not kill a persistent process
like the GUI. If set True a
grass.pygrass.messages.FatalError
exception will be raised in case a fatal
error occurs in the init process, otherwise
sys.exit(1) will be called.
:param skip_db_version_check: Set this True to skip mismatch temporal
database version check.
Recommended to be used only for
upgrade_temporal_database().
"""
# We need to set the correct database backend and several global variables
# from the GRASS mapset specific environment variables of g.gisenv and t.connect
global tgis_backend
global tgis_database
global tgis_database_string
global tgis_dbmi_paramstyle
global tgis_db_version
global raise_on_error
global enable_mapset_check
global enable_timestamp_write
global current_mapset
global current_location
global current_gisdbase
raise_on_error = raise_fatal_error
# We must run t.connect at first to create the temporal database and to
# get the environmental variables
gscript.run_command("t.connect", flags="c")
grassenv = gscript.gisenv()
# Set the global variable for faster access
current_mapset = grassenv["MAPSET"]
current_location = grassenv["LOCATION_NAME"]
current_gisdbase = grassenv["GISDBASE"]
# Check environment variable GRASS_TGIS_RAISE_ON_ERROR
if (
os.getenv("GRASS_TGIS_RAISE_ON_ERROR") == "True"
or os.getenv("GRASS_TGIS_RAISE_ON_ERROR") == "1"
):
raise_on_error = True
# Check if the script library raises on error,
# if so we do the same
if gscript.get_raise_on_error() is True:
raise_on_error = True
# Start the GRASS message interface server
_init_tgis_message_interface(raise_on_error)
# Start the C-library interface server
_init_tgis_c_library_interface()
msgr = get_tgis_message_interface()
msgr.debug(1, "Initiate the temporal database")
msgr.debug(1, ("Raise on error id: %s" % str(raise_on_error)))
ciface = get_tgis_c_library_interface()
driver_string = ciface.get_driver_name()
database_string = ciface.get_database_name()
# Set the mapset check and the timestamp write
if "TGIS_DISABLE_MAPSET_CHECK" in grassenv:
if (
gscript.encode(grassenv["TGIS_DISABLE_MAPSET_CHECK"]) == "True"
or gscript.encode(grassenv["TGIS_DISABLE_MAPSET_CHECK"]) == "1"
):
enable_mapset_check = False
msgr.warning("TGIS_DISABLE_MAPSET_CHECK is True")
if "TGIS_DISABLE_TIMESTAMP_WRITE" in grassenv:
if (
gscript.encode(grassenv["TGIS_DISABLE_TIMESTAMP_WRITE"]) == "True"
or gscript.encode(grassenv["TGIS_DISABLE_TIMESTAMP_WRITE"]) == "1"
):
enable_timestamp_write = False
msgr.warning("TGIS_DISABLE_TIMESTAMP_WRITE is True")
if driver_string is not None and driver_string != "":
driver_string = decode(driver_string)
if driver_string == "sqlite":
tgis_backend = driver_string
try:
import sqlite3
except ImportError:
msgr.error(
"Unable to locate the sqlite SQL Python interface"
" module sqlite3."
)
raise
dbmi = sqlite3
elif driver_string == "pg":
tgis_backend = driver_string
try:
import psycopg2
except ImportError:
msgr.error(
"Unable to locate the Postgresql SQL Python "
"interface module psycopg2."
)
raise
dbmi = psycopg2
else:
msgr.fatal(
_(
"Unable to initialize the temporal DBMI interface. "
"Please use t.connect to specify the driver and the"
" database string"
)
)
else:
# Set the default sqlite3 connection in case nothing was defined
gscript.run_command("t.connect", flags="d")
driver_string = ciface.get_driver_name()
database_string = ciface.get_database_name()
tgis_backend = driver_string
try:
import sqlite3
except ImportError:
msgr.error(
"Unable to locate the sqlite SQL Python interface" " module sqlite3."
)
raise
dbmi = sqlite3
tgis_database_string = database_string
# Set the parameter style
tgis_dbmi_paramstyle = dbmi.paramstyle
# We do not know if the database already exists
db_exists = False
dbif = SQLDatabaseInterfaceConnection()
# Check if the database already exists
if tgis_backend == "sqlite":
# Check path of the sqlite database
if os.path.exists(tgis_database_string):
dbif.connect()
# Check for raster_base table
dbif.execute(
"SELECT name FROM sqlite_master WHERE type='table' "
"AND name='raster_base';"
)
name = dbif.fetchone()
if name and name[0] == "raster_base":
db_exists = True
dbif.close()
elif tgis_backend == "pg":
# Connect to database
dbif.connect()
# Check for raster_base table
dbif.execute(
"SELECT EXISTS(SELECT * FROM information_schema.tables "
"WHERE table_name=%s)",
("raster_base",),
)
if dbif.fetchone()[0]:
db_exists = True
if tgis_db_version > 2:
backup_howto = _(
"Run t.upgrade command to upgrade your temporal database.\n"
"Consider creating a backup of your temporal database to avoid "
"loosing data in case something goes wrong.\n"
)
else:
backup_howto = _(
"You need to export it by "
"restoring the GRASS GIS version used for creating this DB."
"Notes: Use t.rast.export and t.vect.export "
"to make a backup of your"
" existing space time datasets. To save the timestamps of"
" your existing maps and space time datasets, use "
"t.rast.list, t.vect.list and t.rast3d.list. "
"You can register the existing time stamped maps easily if"
" you export columns=id,start_time,end_time into text "
"files and use t.register to register them again in new"
" created space time datasets (t.create). After the backup"
" remove the existing temporal database, a new one will be"
" created automatically.\n"
)
if db_exists is True:
dbif.close()
if skip_db_version_check is True:
return
# Check the version of the temporal database
dbif.connect()
metadata = get_tgis_metadata(dbif)
dbif.close()
if metadata is None:
msgr.fatal(
_(
"Unable to receive temporal database metadata.\n"
"Current temporal database info:%(info)s"
)
% ({"info": get_database_info_string()})
)
# temporal framework version check
for entry in metadata:
if "tgis_version" in entry and entry[1] != str(get_tgis_version()):
msgr.fatal(
_(
"Unsupported temporal database: version mismatch."
"\n %(backup)s Supported temporal API version is:"
" %(api)i.\nPlease update your GRASS GIS "
"installation.\nCurrent temporal database info:"
"%(info)s"
)
% (
{
"backup": backup_howto,
"api": get_tgis_version(),
"info": get_database_info_string(),
}
)
)
# temporal database version check
tgis_db_version_meta = get_tgis_db_version_from_metadata(metadata)
if tgis_db_version_meta != tgis_db_version:
message = _(
"Temporal database version mismatch detected.\n{backup}"
"Supported temporal database version is: {tdb}\n"
"Your existing temporal database version: {ctdb}\n"
"Current temporal database info: {info}".format(
backup=backup_howto,
tdb=tgis_db_version,
ctdb=tgis_db_version_meta,
info=get_database_info_string(),
)
)
if tgis_db_version_meta == 2 and tgis_db_version == 3:
# version 3 is backward compatible with version 2
msgr.warning(message)
else:
msgr.fatal(
_(
"The format of your actual temporal database is "
"not supported any more. {m}".format(m=message)
)
)
return
create_temporal_database(dbif)
###############################################################################
[docs]def get_database_info_string():
dbif = SQLDatabaseInterfaceConnection()
info = "\nDBMI interface:..... " + str(dbif.get_dbmi().__name__)
info += "\nTemporal database:.. " + str(get_tgis_database_string())
return info
###############################################################################
def _create_temporal_database_views(dbif):
"""Create all views in the temporal database (internal use only)
Used by create_temporal_database() and upgrade_temporal_database().
:param dbif: The database interface to be used
"""
template_path = get_sql_template_path()
for sql_filename in (
"raster_views",
"raster3d_views",
"vector_views",
"strds_views",
"str3ds_views",
"stvds_views",
):
sql_filepath = open(
os.path.join(template_path, sql_filename + ".sql"), "r"
).read()
dbif.execute_transaction(sql_filepath)
[docs]def create_temporal_database(dbif):
"""This function will create the temporal database
It will create all tables and triggers that are needed to run
the temporal GIS
:param dbif: The database interface to be used
"""
global tgis_backend
global tgis_version
global tgis_db_version
global tgis_database_string
template_path = get_sql_template_path()
msgr = get_tgis_message_interface()
# Read all SQL scripts and templates
map_tables_template_sql = open(
os.path.join(template_path, "map_tables_template.sql"), "r"
).read()
raster_metadata_sql = open(
os.path.join(get_sql_template_path(), "raster_metadata_table.sql"), "r"
).read()
raster3d_metadata_sql = open(
os.path.join(template_path, "raster3d_metadata_table.sql"), "r"
).read()
vector_metadata_sql = open(
os.path.join(template_path, "vector_metadata_table.sql"), "r"
).read()
stds_tables_template_sql = open(
os.path.join(template_path, "stds_tables_template.sql"), "r"
).read()
strds_metadata_sql = open(
os.path.join(template_path, "strds_metadata_table.sql"), "r"
).read()
str3ds_metadata_sql = open(
os.path.join(template_path, "str3ds_metadata_table.sql"), "r"
).read()
stvds_metadata_sql = open(
os.path.join(template_path, "stvds_metadata_table.sql"), "r"
).read()
# Create the raster, raster3d and vector tables SQL statements
raster_tables_sql = map_tables_template_sql.replace("GRASS_MAP", "raster")
vector_tables_sql = map_tables_template_sql.replace("GRASS_MAP", "vector")
raster3d_tables_sql = map_tables_template_sql.replace("GRASS_MAP", "raster3d")
# Create the space-time raster, raster3d and vector dataset tables
# SQL statements
strds_tables_sql = stds_tables_template_sql.replace("STDS", "strds")
stvds_tables_sql = stds_tables_template_sql.replace("STDS", "stvds")
str3ds_tables_sql = stds_tables_template_sql.replace("STDS", "str3ds")
msgr.message(_("Creating temporal database: %s" % (str(tgis_database_string))))
if tgis_backend == "sqlite":
# We need to create the sqlite3 database path if it does not exist
tgis_dir = os.path.dirname(tgis_database_string)
if not os.path.exists(tgis_dir):
try:
os.makedirs(tgis_dir)
except Exception as e:
msgr.fatal(
_(
"Unable to create SQLite temporal database\n"
"Exception: %s\nPlease use t.connect to set a "
"read- and writable temporal database path" % (e)
)
)
# Set up the trigger that takes care of
# the correct deletion of entries across the different tables
delete_trigger_sql = open(
os.path.join(template_path, "sqlite3_delete_trigger.sql"), "r"
).read()
indexes_sql = open(
os.path.join(template_path, "sqlite3_indexes.sql"), "r"
).read()
else:
# Set up the trigger that takes care of
# the correct deletion of entries across the different tables
delete_trigger_sql = open(
os.path.join(template_path, "postgresql_delete_trigger.sql"), "r"
).read()
indexes_sql = open(
os.path.join(template_path, "postgresql_indexes.sql"), "r"
).read()
# Connect now to the database
if dbif.connected is not True:
dbif.connect()
# Execute the SQL statements
# Create the global tables for the native grass datatypes
dbif.execute_transaction(raster_tables_sql)
dbif.execute_transaction(raster_metadata_sql)
dbif.execute_transaction(vector_tables_sql)
dbif.execute_transaction(vector_metadata_sql)
dbif.execute_transaction(raster3d_tables_sql)
dbif.execute_transaction(raster3d_metadata_sql)
# Create the tables for the new space-time datatypes
dbif.execute_transaction(strds_tables_sql)
dbif.execute_transaction(strds_metadata_sql)
dbif.execute_transaction(stvds_tables_sql)
dbif.execute_transaction(stvds_metadata_sql)
dbif.execute_transaction(str3ds_tables_sql)
dbif.execute_transaction(str3ds_metadata_sql)
# Create views
_create_temporal_database_views(dbif)
# The delete trigger
dbif.execute_transaction(delete_trigger_sql)
# The indexes
dbif.execute_transaction(indexes_sql)
# Create the tgis metadata table to store the database
# initial configuration
# The metadata table content
metadata = {}
metadata["tgis_version"] = tgis_version
metadata["tgis_db_version"] = tgis_db_version
metadata["creation_time"] = datetime.today()
_create_tgis_metadata_table(metadata, dbif)
dbif.close()
###############################################################################
[docs]def upgrade_temporal_database(dbif):
"""This function will upgrade the temporal database if needed.
It will update all tables and triggers that are requested by
currently supported TGIS DB version.
:param dbif: The database interface to be used
"""
global tgis_database_string
global tgis_db_version
metadata = get_tgis_metadata(dbif)
msgr = get_tgis_message_interface()
if metadata is None:
msgr.fatal(
_(
"Unable to receive temporal database metadata.\n"
"Current temporal database info:%(info)s"
)
% ({"info": get_database_info_string()})
)
upgrade_db_from = None
for entry in metadata:
if "tgis_db_version" in entry and entry[1] != str(tgis_db_version):
upgrade_db_from = entry[1]
break
if upgrade_db_from is None:
msgr.message(_("Temporal database is up-to-date. Operation canceled"))
dbif.close()
return
template_path = get_sql_template_path()
try:
upgrade_db_sql = open(
os.path.join(
template_path,
"upgrade_db_%s_to_%s.sql" % (upgrade_db_from, tgis_db_version),
),
"r",
).read()
except FileNotFoundError:
msgr.fatal(
_("Unsupported TGIS DB upgrade scenario: from version %s to %s")
% (upgrade_db_from, tgis_db_version)
)
drop_views_sql = open(os.path.join(template_path, "drop_views.sql"), "r").read()
msgr.message(
_("Upgrading temporal database <%s> from version %s to %s...")
% (tgis_database_string, upgrade_db_from, tgis_db_version)
)
# Drop views
dbif.execute_transaction(drop_views_sql)
# Perform upgrade
dbif.execute_transaction(upgrade_db_sql)
# Recreate views
_create_temporal_database_views(dbif)
dbif.close()
###############################################################################
def _create_tgis_metadata_table(content, dbif=None):
"""!Create the temporal gis metadata table which stores all metadata
information about the temporal database.
:param content: The dictionary that stores the key:value metadata
that should be stored in the metadata table
:param dbif: The database interface to be used
"""
dbif, connection_state_changed = init_dbif(dbif)
statement = "CREATE TABLE tgis_metadata (key VARCHAR NOT NULL, value VARCHAR);\n"
dbif.execute_transaction(statement)
for key in content.keys():
statement = (
"INSERT INTO tgis_metadata (key, value) VALUES "
+ "('%s' , '%s');\n" % (str(key), str(content[key]))
)
dbif.execute_transaction(statement)
if connection_state_changed:
dbif.close()
###############################################################################
[docs]class SQLDatabaseInterfaceConnection:
def __init__(self):
self.tgis_mapsets = get_available_temporal_mapsets()
self.current_mapset = get_current_mapset()
self.connections = {}
self.connected = False
self.unique_connections = {}
for mapset in self.tgis_mapsets.keys():
driver, dbstring = self.tgis_mapsets[mapset]
if dbstring not in self.unique_connections.keys():
self.unique_connections[dbstring] = DBConnection(
backend=driver, dbstring=dbstring
)
self.connections[mapset] = self.unique_connections[dbstring]
self.msgr = get_tgis_message_interface()
[docs] def get_dbmi(self, mapset=None):
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
return self.connections[mapset].dbmi
[docs] def rollback(self, mapset=None):
"""
Roll back the last transaction. This must be called
in case a new query should be performed after a db error.
This is only relevant for postgresql database.
"""
if mapset is None:
mapset = self.current_mapset
[docs] def connect(self):
"""Connect to the DBMI to execute SQL statements
Supported backends are sqlite3 and postgresql
"""
for mapset in self.tgis_mapsets.keys():
driver, dbstring = self.tgis_mapsets[mapset]
conn = self.connections[mapset]
if conn.is_connected() is False:
conn.connect(dbstring)
self.connected = True
[docs] def is_connected(self):
return self.connected
[docs] def close(self):
"""Close the DBMI connection
There may be several temporal databases in a location, hence
close all temporal databases that have been opened.
"""
for key in self.unique_connections.keys():
self.unique_connections[key].close()
self.connected = False
[docs] def mogrify_sql_statement(self, content, mapset=None):
"""Return the SQL statement and arguments as executable SQL string
:param content: The content as tuple with two entries, the first
entry is the SQL statement with DBMI specific
place holder (?), the second entry is the argument
list that should substitute the place holder.
:param mapset: The mapset of the abstract dataset or temporal
database location, if None the current mapset
will be used
"""
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
if mapset not in self.tgis_mapsets.keys():
self.msgr.fatal(
_(
"Unable to mogrify sql statement. "
+ self._create_mapset_error_message(mapset)
)
)
return self.connections[mapset].mogrify_sql_statement(content)
[docs] def check_table(self, table_name, mapset=None):
"""Check if a table exists in the temporal database
:param table_name: The name of the table to be checked for existence
:param mapset: The mapset of the abstract dataset or temporal
database location, if None the current mapset
will be used
:returns: True if the table exists, False otherwise
TODO:
There may be several temporal databases in a location, hence
the mapset is used to query the correct temporal database.
"""
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
if mapset not in self.tgis_mapsets.keys():
self.msgr.fatal(
_("Unable to check table. " + self._create_mapset_error_message(mapset))
)
return self.connections[mapset].check_table(table_name)
[docs] def execute(self, statement, args=None, mapset=None):
"""
:param mapset: The mapset of the abstract dataset or temporal
database location, if None the current mapset
will be used
"""
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
if mapset not in self.tgis_mapsets.keys():
self.msgr.fatal(
_(
"Unable to execute sql statement. "
+ self._create_mapset_error_message(mapset)
)
)
return self.connections[mapset].execute(statement, args)
[docs] def fetchone(self, mapset=None):
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
if mapset not in self.tgis_mapsets.keys():
self.msgr.fatal(
_("Unable to fetch one. " + self._create_mapset_error_message(mapset))
)
return self.connections[mapset].fetchone()
[docs] def fetchall(self, mapset=None):
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
if mapset not in self.tgis_mapsets.keys():
self.msgr.fatal(
_("Unable to fetch all. " + self._create_mapset_error_message(mapset))
)
return self.connections[mapset].fetchall()
[docs] def execute_transaction(self, statement, mapset=None):
"""Execute a transactional SQL statement
The BEGIN and END TRANSACTION statements will be added automatically
to the sql statement
:param statement: The executable SQL statement or SQL script
"""
if mapset is None:
mapset = self.current_mapset
mapset = decode(mapset)
if mapset not in self.tgis_mapsets.keys():
self.msgr.fatal(
_(
"Unable to execute transaction. "
+ self._create_mapset_error_message(mapset)
)
)
return self.connections[mapset].execute_transaction(statement)
def _create_mapset_error_message(self, mapset):
return (
"You have no permission to "
"access mapset <%(mapset)s>, or "
"mapset <%(mapset)s> has no temporal database. "
"Accessible mapsets are: <%(mapsets)s>"
% {"mapset": decode(mapset), "mapsets": ",".join(self.tgis_mapsets.keys())}
)
###############################################################################
[docs]class DBConnection:
"""This class represents the database interface connection
and provides access to the chosen backend modules.
The following DBMS are supported:
- sqlite via the sqlite3 standard library
- postgresql via psycopg2
"""
def __init__(self, backend=None, dbstring=None):
"""Constructor of a database connection
param backend:The database backend sqlite or pg
param dbstring: The database connection string
"""
self.connected = False
if backend is None:
global tgis_backend
if decode(tgis_backend) == "sqlite":
self.dbmi = sqlite3
else:
self.dbmi = psycopg2
else:
if decode(backend) == "sqlite":
self.dbmi = sqlite3
else:
self.dbmi = psycopg2
if dbstring is None:
global tgis_database_string
self.dbstring = tgis_database_string
self.dbstring = dbstring
self.msgr = get_tgis_message_interface()
self.msgr.debug(
1,
"DBConnection constructor:"
"\n backend: %s"
"\n dbstring: %s" % (backend, self.dbstring),
)
def __del__(self):
if self.connected is True:
self.close()
[docs] def is_connected(self):
return self.connected
[docs] def rollback(self):
"""
Roll back the last transaction. This must be called
in case a new query should be performed after a db error.
This is only relevant for postgresql database.
"""
if self.dbmi.__name__ == "psycopg2":
if self.connected:
self.connection.rollback()
[docs] def connect(self, dbstring=None):
"""Connect to the DBMI to execute SQL statements
Supported backends are sqlite3 and postgresql
param dbstring: The database connection string
"""
# Connection in the current mapset
if dbstring is None:
dbstring = self.dbstring
dbstring = decode(dbstring)
try:
if self.dbmi.__name__ == "sqlite3":
self.connection = self.dbmi.connect(
dbstring,
detect_types=self.dbmi.PARSE_DECLTYPES | self.dbmi.PARSE_COLNAMES,
)
self.connection.row_factory = self.dbmi.Row
self.connection.isolation_level = None
self.connection.text_factory = str
self.cursor = self.connection.cursor()
self.cursor.execute("PRAGMA synchronous = OFF")
self.cursor.execute("PRAGMA journal_mode = MEMORY")
elif self.dbmi.__name__ == "psycopg2":
self.connection = self.dbmi.connect(dbstring)
# self.connection.set_isolation_level(dbmi.extensions.ISOLATION_LEVEL_AUTOCOMMIT)
self.cursor = self.connection.cursor(
cursor_factory=self.dbmi.extras.DictCursor
)
self.connected = True
except Exception as e:
self.msgr.fatal(
_(
"Unable to connect to %(db)s database: "
'%(string)s\nException: "%(ex)s"\nPlease use'
" t.connect to set a read- and writable "
"temporal database backend"
)
% (
{
"db": self.dbmi.__name__,
"string": tgis_database_string,
"ex": e,
}
)
)
[docs] def close(self):
"""Close the DBMI connection
TODO:
There may be several temporal databases in a location, hence
close all temporal databases that have been opened. Use a dictionary
to manage different connections.
"""
self.connection.commit()
self.cursor.close()
self.connected = False
[docs] def mogrify_sql_statement(self, content):
"""Return the SQL statement and arguments as executable SQL string
TODO:
Use the mapset argument to identify the correct database driver
:param content: The content as tuple with two entries, the first
entry is the SQL statement with DBMI specific
place holder (?), the second entry is the argument
list that should substitute the place holder.
:param mapset: The mapset of the abstract dataset or temporal
database location, if None the current mapset
will be used
Usage:
.. code-block:: python
>>> init()
>>> dbif = SQLDatabaseInterfaceConnection()
>>> dbif.mogrify_sql_statement(
... [
... "SELECT ctime FROM raster_base WHERE id = ?",
... [
... "soil@PERMANENT",
... ],
... ]
... )
"SELECT ctime FROM raster_base WHERE id = 'soil@PERMANENT'"
"""
sql = content[0]
args = content[1]
if self.dbmi.__name__ == "psycopg2":
if len(args) == 0:
return sql
else:
if self.connected:
try:
return self.cursor.mogrify(sql, args)
except Exception as exc:
print(sql, args)
raise exc
else:
self.connect()
statement = self.cursor.mogrify(sql, args)
self.close()
return statement
elif self.dbmi.__name__ == "sqlite3":
if len(args) == 0:
return sql
else:
# Unfortunately as sqlite does not support
# the transformation of sql strings and qmarked or
# named arguments we must make our hands dirty
# and do it by ourself. :(
# Doors are open for SQL injection because of the
# limited python sqlite3 implementation!!!
pos = 0
count = 0
maxcount = 100
statement = sql
while count < maxcount:
pos = statement.find("?", pos + 1)
if pos == -1:
break
if args[count] is None:
statement = "%sNULL%s" % (
statement[0:pos],
statement[pos + 1 :],
)
elif isinstance(args[count], int):
statement = "%s%d%s" % (
statement[0:pos],
args[count],
statement[pos + 1 :],
)
elif isinstance(args[count], float):
statement = "%s%f%s" % (
statement[0:pos],
args[count],
statement[pos + 1 :],
)
elif isinstance(args[count], datetime):
statement = "%s'%s'%s" % (
statement[0:pos],
str(args[count]),
statement[pos + 1 :],
)
else:
# Default is a string, this works for datetime
# objects too
statement = "%s'%s'%s" % (
statement[0:pos],
str(args[count]),
statement[pos + 1 :],
)
count += 1
return statement
[docs] def check_table(self, table_name):
"""Check if a table exists in the temporal database
:param table_name: The name of the table to be checked for existence
:param mapset: The mapset of the abstract dataset or temporal
database location, if None the current mapset
will be used
:returns: True if the table exists, False otherwise
TODO:
There may be several temporal databases in a location, hence
the mapset is used to query the correct temporal database.
"""
table_exists = False
connected = False
if not self.connected:
self.connect()
connected = True
# Check if the database already exists
if self.dbmi.__name__ == "sqlite3":
self.cursor.execute(
"SELECT name FROM sqlite_master WHERE "
"type='table' AND name='%s';" % table_name
)
name = self.cursor.fetchone()
if name and name[0] == table_name:
table_exists = True
else:
# Check for raster_base table
self.cursor.execute(
"SELECT EXISTS(SELECT * FROM information_schema.tables "
"WHERE table_name=%s)",
("%s" % table_name,),
)
if self.cursor.fetchone()[0]:
table_exists = True
if connected:
self.close()
return table_exists
[docs] def execute(self, statement, args=None):
"""Execute a SQL statement
:param statement: The executable SQL statement or SQL script
"""
connected = False
if not self.connected:
self.connect()
connected = True
try:
if args:
self.cursor.execute(statement, args)
else:
self.cursor.execute(statement)
except:
if connected:
self.close()
self.msgr.error(_("Unable to execute :\n %(sql)s" % {"sql": statement}))
raise
if connected:
self.close()
[docs] def fetchone(self):
if self.connected:
return self.cursor.fetchone()
return None
[docs] def fetchall(self):
if self.connected:
return self.cursor.fetchall()
return None
[docs] def execute_transaction(self, statement, mapset=None):
"""Execute a transactional SQL statement
The BEGIN and END TRANSACTION statements will be added automatically
to the sql statement
:param statement: The executable SQL statement or SQL script
"""
connected = False
if not self.connected:
self.connect()
connected = True
sql_script = ""
sql_script += "BEGIN TRANSACTION;\n"
sql_script += statement
sql_script += "END TRANSACTION;"
try:
if self.dbmi.__name__ == "sqlite3":
self.cursor.executescript(statement)
else:
self.cursor.execute(statement)
self.connection.commit()
except:
if connected:
self.close()
self.msgr.error(
_("Unable to execute transaction:\n %(sql)s" % {"sql": statement})
)
raise
if connected:
self.close()
###############################################################################
[docs]def init_dbif(dbif):
"""This method checks if the database interface connection exists,
if not a new one will be created, connected and True will be returned.
If the database interface exists but is not connected, the connection
will be established.
:returns: the tuple (dbif, connection_state_changed)
Usage code sample:
.. code-block:: python
dbif, connection_state_changed = tgis.init_dbif(None)
sql = dbif.mogrify_sql_statement(
["SELECT * FROM raster_base WHERE ? = ?"], ["id", "soil@PERMANENT"]
)
dbif.execute_transaction(sql)
if connection_state_changed:
dbif.close()
"""
connection_state_changed = False
if dbif is None:
dbif = SQLDatabaseInterfaceConnection()
dbif.connect()
connection_state_changed = True
elif dbif.is_connected() is False:
dbif.connect()
connection_state_changed = True
return dbif, connection_state_changed
###############################################################################
if __name__ == "__main__":
import doctest
doctest.testmod()
