Initial Pass Informix DBHelper

etlhelper/db_helper_factory.py

@@ -7,6 +7,7 @@
 from etlhelper.db_helpers.postgres import PostgresDbHelper
 from etlhelper.db_helpers.mssql import MSSQLDbHelper
 from etlhelper.db_helpers.sqlite import SQLiteDbHelper
+from etlhelper.db_helpers.informix import InformixDbHelper
 from etlhelper.exceptions import ETLHelperHelperError
 
 
@@ -72,3 +73,5 @@ def from_dbtype(self, dbtype):
                                   MSSQLDbHelper)
 DB_HELPER_FACTORY.register_helper('SQLITE', "<class 'sqlite3.Connection'>",
                                   SQLiteDbHelper)
+DB_HELPER_FACTORY.register_helper('INFORMIX', "<class 'ibm_db_dbi.Connection'>",
+                                  InformixDbHelper)

etlhelper/db_helpers/informix.py

@@ -0,0 +1,79 @@
+"""
+Database helper for Postgres
+"""
+from contextlib import contextmanager
+
+from etlhelper.db_helpers.db_helper import DbHelper
+
+
+class InformixDbHelper(DbHelper):
+    """
+    Postgres db helper class
+    """
+    def __init__(self):
+        super().__init__()
+        try:
+            import ibm_db_dbi
+            self.sql_exceptions = (ibm_db_dbi.ProgrammingError)
+            self._connect_func = ibm_db_dbi.connect
+            self.connect_exceptions = (ibm_db_dbi.OperationalError)
+            self.required_params = {'hostname', 'port', 'database', 'uid'}
+        except ImportError:
+            print("The Informix Python libraries could not be found.\n"
+                  "Run: python -m pip install ibm_db")
+
+    def get_connection_string(self, db_params, password_variable):
+        """
+        Return a connection string
+        :param db_params: DbParams
+        :param password: str, password
+        :return: str
+        """
+        # Prepare connection string
+        password = self.get_password(password_variable)
+        return f'database={db_params.database};hostname={db_params.hostname};' \
+               f'port={db_params.port};protocol=tcpip;uid={db_params.uid};pwd={password}'
+
+    def get_sqlalchemy_connection_string(self, db_params, password_variable):
+        """
+        Returns connection string for sql alchemy
+        """
+        password = self.get_password(password_variable)
+        return (f'postgresql://{db_params.user}:{password}@'
+                f'{db_params.host}:{db_params.port}/{db_params.dbname}')
+
+    @staticmethod
+    def executemany(cursor, query, chunk):
+        """
+        Call execute_batch method for PostGres.
+
+        :param cursor: Open database cursor.
+        :param query: str, SQL query
+        :param chunk: list, Rows of parameters.
+        """
+        # Here we use execute_batch to send multiple inserts to db at once.
+        # This is faster than execute_many() because it results in fewer db
+        # calls.  execute_values() or preparing single statement with
+        # mogrify() were not used because resulting input statement is less
+        # clear and selective formatting of inputs for spatial vs non-spatial
+        # tables adds significant code complexity.
+        # See following for background:
+        # https://github.com/psycopg/psycopg2/issues/491#issuecomment-276551038
+        # https://www.compose.com/articles/formatted-sql-in-python-with-psycopgs-mogrify/
+        from psycopg2.extras import execute_batch
+
+        execute_batch(cursor, query, chunk, page_size=len(chunk))
+
+
+    @staticmethod
+    @contextmanager
+    def cursor(conn):
+        """
+        Return a cursor on current connection.  This implementation allows
+        SQLite cursor to be used as context manager as with other db types.
+        """
+        try:
+            cursor = conn.cursor()
+            yield cursor
+        finally:
+            cursor.close()

requirements.txt

@@ -1,18 +1,72 @@
-flake8
-ipdb
-ipython
-pytest
-pytest-cov
-Sphinx
-sphinxcontrib-applehelp
-sphinxcontrib-devhelp
-sphinxcontrib-htmlhelp
-sphinxcontrib-jsmath
-sphinxcontrib-qthelp
-sphinxcontrib-serializinghtml
-sphinx_rtd_theme
-versioneer
-cx-oracle
-pyodbc
-psycopg2-binary
-twine
+alabaster==0.7.12
+attrs==19.3.0
+Babel==2.8.0
+backcall==0.1.0
+bleach==3.1.0
+certifi==2019.11.28
+cffi==1.13.2
+chardet==3.0.4
+coverage==5.0.3
+cryptography==2.8
+cx-Oracle==7.3.0
+decorator==4.4.1
+docutils==0.16
+entrypoints==0.3
+flake8==3.7.9
+ibm-db==3.0.1
+idna==2.8
+imagesize==1.2.0
+importlib-metadata==1.5.0
+ipdb==0.12.3
+ipython==7.12.0
+ipython-genutils==0.2.0
+jedi==0.16.0
+jeepney==0.4.2
+Jinja2==2.11.1
+keyring==21.1.0
+MarkupSafe==1.1.1
+mccabe==0.6.1
+more-itertools==8.2.0
+packaging==20.1
+parso==0.6.1
+pexpect==4.8.0
+pickleshare==0.7.5
+pkginfo==1.5.0.1
+pluggy==0.13.1
+prompt-toolkit==3.0.3
+psycopg2-binary==2.8.4
+ptyprocess==0.6.0
+py==1.8.1
+pycodestyle==2.5.0
+pycparser==2.19
+pyflakes==2.1.1
+Pygments==2.5.2
+pyodbc==4.0.28
+pyparsing==2.4.6
+pytest==5.3.5
+pytest-cov==2.8.1
+pytest-sugar==0.9.2
+pytz==2019.3
+readme-renderer==24.0
+requests==2.22.0
+requests-toolbelt==0.9.1
+SecretStorage==3.1.2
+six==1.14.0
+snowballstemmer==2.0.0
+Sphinx==2.3.1
+sphinx-rtd-theme==0.4.3
+sphinxcontrib-applehelp==1.0.1
+sphinxcontrib-devhelp==1.0.1
+sphinxcontrib-htmlhelp==1.0.2
+sphinxcontrib-jsmath==1.0.1
+sphinxcontrib-qthelp==1.0.2
+sphinxcontrib-serializinghtml==1.1.3
+termcolor==1.1.0
+tqdm==4.42.1
+traitlets==4.3.3
+twine==3.1.1
+urllib3==1.25.8
+versioneer==0.18
+wcwidth==0.1.8
+webencodings==0.5.1
+zipp==2.1.0

test/unit/test_db_helpers.py

@@ -1,11 +1,12 @@
 """Unit tests for db_helpers module."""
-from unittest.mock import Mock
-import pytest
+import pyodbc
 import sqlite3
+from unittest.mock import Mock
 
 import cx_Oracle
-import pyodbc
+import ibm_db_dbi
 import psycopg2
+import pytest
 
 from etlhelper import DbParams
 from etlhelper.db_helper_factory import DB_HELPER_FACTORY
@@ -26,6 +27,8 @@
 
 SQLITEDB = DbParams(dbtype='SQLITE', filename='/myfile.db')
 
+INFORMIXDB = DbParams(dbtype='INFORMIX', database='testDb', hostname='localhost', port='1111', protocol='tcpip',uid='user' )
+
 
 def test_oracle_sql_exceptions():
     helper = OracleDbHelper()
@@ -43,7 +46,8 @@ def test_oracle_connect_exceptions():
      'DRIVER=test driver;SERVER=tcp:server;PORT=1521;DATABASE=testdb;UID=testuser;PWD=mypassword'), # NOQA
     (POSTGRESDB, psycopg2,
      'host=server port=1521 dbname=testdb user=testuser password=mypassword'),
-    (SQLITEDB, sqlite3, '/myfile.db')
+    (SQLITEDB, sqlite3, '/myfile.db'),
+    (INFORMIXDB, ibm_db_dbi, 'database=testDb;hostname=localhost;port=1111;protocol=tcpip;uid=user;pwd=mypassword')
 ])
 def test_connect(monkeypatch, db_params, driver, expected):
     # Arrange