SnowConvert Scripts Helpers
SnowConvert Helpers is a set of classes with functions designed to facilitate the conversion of Teradata script files to Python files that Snowflake can interpret.
SnowConvert for Teradata can take in any Teradata SQL or scripts (BTEQ, FastLoad, MultiLoad, and TPump) and convert them to functionally equivalent Snowflake SQL, JavaScript embedded in Snowflake SQL, and Python. Any output Python code from SnowConvert will call functions from these helper classes to complete the conversion and create a functionally equivalent output in Snowflake.
The Snowflake Connector for Python will also be called in order to connect to your Snowflake account and run the output Python code created by SnowConvert.
The latest version information of the package can be found here.
Script Migration
Source
Suppose you have the following BTEQ code to be migrated.
insert into table1 values(1, 2);
insert into table1 values(3, 4);
insert into table1 values(5, 6);Output
You should get an output like the one below.
import os
import sys
import snowconvert.helpers
from snowconvert.helpers import Export
from snowconvert.helpers import exec
con = None
def main():
snowconvert.helpers.configure_log()
con = snowconvert.helpers.log_on()
exec("""
INSERT INTO PUBLIC.table1 VALUES (1, 2)
""")
exec("""
INSERT INTO PUBLIC.table1 VALUES (3, 4)
""")
exec("""
INSERT INTO PUBLIC.table1 VALUES (5, 6)
""")
snowconvert.helpers.quit_application()
if __name__ == "__main__":
main()Getting Started
To install the package, you should run the following command in your python environment. If you're not familiar with installing packages in Python, visit the following page on python packages (https://packaging.python.org/tutorials/installing-packages/).
Once your package is installed, you will be able to run the script migrated code in Python.
Run the code
To run the migrated code, you just have to open the Command Prompt or the Terminal and execute the following command.
If the script has no errors, you will get in your console an output like the one below.
Passing connection parameters
There are several ways to pass the connection parameters to the connection of the database:
As parameters in the function call snowconvert.helpers.log_on inside the python file.
As positional parameters with the specific order of user, password, account, database, warehouse, and role when the python is being executed from the command line.
As named parameters with no order restriction of SNOW_USER, SNOW_PASSWORD, SNOW_ACCOUNT, SNOW_DATABASE, SNOW_WAREHOUSE, SNOW_ROLE, SNOW_QUERYTAG, SNOWAUTHENTICATOR and SNOWTOKEN when the python is being executed from the command line and any of them are passed like --param-VARNAME=VALUE.
As environment variables named SNOW_USER, SNOW_PASSWORD, SNOW_ACCOUNT, SNOW_DATABASE, SNOW_WAREHOUSE, SNOW_ROLE, SNOW_QUERYTAG, SNOWAUTHENTICATOR and SNOWTOKEN before python execution.
The previous order specified is the way to determine the precedence.
Parameters in the function call
They can be set as positional parameters in the function call as follows.
Or they can be set any of the named parameters in any order in the function call as follows.
Positional parameters
They need to be set in the specific order in the command line as follows.
Or they can be set only some of the parameters but always starting with the user parameter as follows.
Named parameters
They can be set any of the named parameters in any order in the command line as follows (use a single line, multiline shown for readability reasons).
Environment variables
Before calling the python script, any of the following environment variables can be set:
SNOW_USER
SNOW_PASSWORD
SNOW_ACCOUNT
SNOW_DATABASE
SNOW_WAREHOUSE
SNOW_ROLE
SNOW_QUERYTAG
SNOW_AUTHENTICATOR
SNOW_TOKEN
Example of passing environment variables
Here is an example of using SNOW_AUTHENTICATOR, SNOW_USER and SNOW_PASSWORD. They must be defined before running the output python file and then run the python generated file.
Enabling Logging
To enable logging, you should enable an environment variable called SNOW_LOGGING set as true.
Then, if you want to customize the logging configuration you can pass a parameter to the snowconvert.helpers.configure_log() method like this:
The configuration file should contain the next structure. For more information about python logging, click here
Snowflake
Once any migrated code you have been executed, you can go to Snowflake and check your changes or deployments.
You will be able to see the rows you have inserted in the example above.
Local Helpers Documentation
First of all, it is required to install the python package named pydoc (Available since version 2.0.2 of snowconvert-helpers).
Then in order to display the python documentation of the package snowconvert-helpers, you should go to a folder where you have the converted output code and you have a python output.
Located in this directory you need to run:
The console will open your preferred browser with the HTML help of the documentation for all the installed packages.
This will open the browser with the documentation of your code like:
Scroll thru the end of the page to see the installed packages. And you will see something similar to:
Clicking in the SnowConvert(package) you will see something like:
Clicking in the module helpers will display a screen similar to:
Then you can scroll thru the functions and classes of the module.
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