Teradata (via Collector method) - v3.1.0
About Collectors
Collectors are extractors that are developed and managed by you (A customer of K).
KADA provides python libraries that customers can use to quickly deploy a Collector.
Why you should use a Collector
There are several reasons why you may use a collector vs the direct connect extractor:
You are using the KADA SaaS offering and it cannot connect to your sources due to firewall restrictions
You want to push metadata to KADA rather than allow it pull data for Security reasons
You want to inspect the metadata before pushing it to K
Using a collector requires you to manage
Deploying and orchestrating the extract code
Managing a high water mark so the extract only pull the latest metadata
Storing and pushing the extracts to your K instance.
Pre-requisites
Python 3.6 - 3.10
Access to K landing directory
Access to Teradata
Step 1: Create Teradata permission
This step is performed by the Teradata Admin.
Login to Teradata
Create a <KADA_USER> account with read access to the following tables
dbc.DBQLOGTBL
dbc.DBQLSQLTBL
dbc.TABLESV
dbc.COLUMNSV
dbc.INDICESV
dbc.ALL_RI_CHILDRENV
dbc.TVM
dbc.DBASE
dbc.TABLES
dbc.TEXTTBLIf you have PDCR enabled then also need to access to these tables
pdcrinfo.DBQLOGTBL_HST
pdcrinfo.DBQLSQLTBL_HSTSHOW command access on tables, macros, procedures.
CODE-- apply at the database level GRANT SHOW ON <DATABASE_NAME> TO <KADA_USER> -- or apply to individual tables to limit to a subset of tables GRANT SHOW ON <DATABASE_NAME> TO <KADA_USER>
Step 2: Create the Source in K
Go to Settings, Select Sources and click Add Source
Select Teradata as the Source Type
Select “Load from File system” option
Give the source a Name - e.g. Teradata Production
Add the Host name for the Teradata Server
Click Finish Setup
Step 3: Getting Access to the Source Landing Directory
When using a Collector you will push metadata to a K landing directory.
To find your landing directory you will need to
Go to Platform Settings - Settings. Note down the value of this setting
If using Azure: storage_azure_storage_account
if using AWS:
storage_root_folder - the AWS s3 bucket
storage_aws_region - the region where the AWS s3 bucket is hosted
Go to Sources - Edit the Source you have configured. Note down the landing directory in the About this Source section
To connect to the landing directory you will need
If using Azure: a SAS token to push data to the landing directory. Request this from KADA Support (support@kada.ai)
if using AWS:
an Access key and Secret. Request this from KADA Support (support@kada.ai)
OR provide your IAM role to KADA Support to provision access.
Step 4: Install the Collector
It is recommended to use a python environment such as pyenv or pipenv if you are not intending to install this package at the system level.
Some python packages also have dependencies on the OS level packages, so you may be required to install additional OS packages if the below fails to install.
You can download the latest Core Library and whl via Platform Settings → Sources → Download Collectors
![](../__attachments/2056814593/image-20230507-082525.png?inst-v=56ba31f4-fc44-4351-81e8-df11c3948b3e)
Run the following command to install the collector
pip install kada_collectors_extractors_<version>-none-any.whl
You will also need to install the common library kada_collectors_lib for this collector to function properly.
pip install kada_collectors_lib-<version>-none-any.whl
Step 5: Configure the Collector
The collector requires a set of parameters to connect to and extract metadata from Teradata.
FIELD | FIELD TYPE | DESCRIPTION | EXAMPLE |
---|---|---|---|
server | string | Teradata server, if you use a custom port other than 1025 you can specify it as part of the server e.g. “10.1.18.19:130” | “10.1.18.19” |
host | string | The onboarded host value in K for the Teradata server | “myteradata“ |
username | string | Username to log into the Teradata account | “myuser” |
password | string | Password to log into the Teradata account |
|
pdcr_enabled | boolean | Is PDCR enabled on teradata? See Teradata Online Documentation | Quick access to technical manuals | false |
output_path | string | Absolute path to the output location where files are to be written | “/tmp/output” |
mask | boolean | To enable masking or not | true |
compress | boolean | To gzip the output or not | true |
meta_only | boolean | To extract metadata only or not | false |
These parameters can be added directly into the run or you can use pass the parameters in via a JSON file.
KADA provides an out of the box script that reads a configuration JSON file and runs the extractor. Below is the configuration file.
kada_teradata_extractor_config.json
{
"server": "",
"host": "",
"username": "",
"password": "",
"pdcr_enabled": true,
"database_name": "",
"output_path": "/tmp/output",
"mask": true,
"compress": true,
"meta_only": false
}
Step 6: Run the Collector
The following code is an example of how to run the extractor. You may need to uplift this code to meet any code standards at your organisation.
This can be executed in any python environment where the whl has been installed. It will produce and read a high water mark file from the same directory as the execution called teradata_hwm.txt and produce files according to the configuration JSON.
This is the wrapper script: kada_teradata_extractor.py
import os
import argparse
from kada_collectors.extractors.utils import load_config, get_hwm, publish_hwm, get_generic_logger
from kada_collectors.extractors.teradata import Extractor
get_generic_logger('root') # Set to use the root logger, you can change the context accordingly or define your own logger
_type = 'teradata'
dirname = os.path.dirname(__file__)
filename = os.path.join(dirname, 'kada_{}_extractor_config.json'.format(_type))
parser = argparse.ArgumentParser(description='KADA Teradata Extractor.')
parser.add_argument('--config', '-c', dest='config', default=filename, help='Location of the configuration json, default is the config json in the same directory as the script.')
args = parser.parse_args()
start_hwm, end_hwm = get_hwm(_type)
ext = Extractor(**load_config(args.config))
ext.test_connection()
ext.run(**{"start_hwm": start_hwm, "end_hwm": end_hwm})
publish_hwm(_type, end_hwm)
Advance options:
If you wish to maintain your own high water mark files elsewhere you can use the above section’s script as a guide on how to call the extractor. The configuration file is simply the keyword arguments in JSON format. Refer to this document for more information Collector Integration General Notes | Storing-HWM-in-another-location
If you are handling external arguments of the runner yourself, you’ll need to consider additional items for the run method. Refer to this document for more information Collector Integration General Notes | The-run-method
from kada_collectors.extractors.teradata import Extractor
kwargs = {my args} # However you choose to construct your args
hwm_kwrgs = {"start_hwm": "end_hwm": } # The hwm values
ext = Extractor(**kwargs)
ext.run(**hwm_kwrgs)
class Extractor(username: str = None, password: str = None, server: str = None, \
host: str = None, pdcr_enabled: bool = None, database_name: str = None, \
output_path: str = './output', mask: bool = False, compress: bool = False, \
meta_only: bool = False) -> None
username: username to sign into teradata
password: password to sign into teradata
server: teradata host
host: Onboarded host value for teradata in K
pdcr_enabled: Does teradata hace pdcr enabled?
database_name: Onboarded K database name
output_path: full or relative path to where the outputs should go
mask: To mask the META/DATABASE_LOG files or not
compress: To gzip output files or not
meta_only: To extract metadata only or not
Step 7: Check the Collector Outputs
K Extracts
A set of files (eg metadata, databaselog, linkages, events etc) will be generated. These files will appear in the output_path directory you set in the configuration details
High Water Mark File
A high water mark file is created in the same directory as the execution called teradata_hwm.txt and produce files according to the configuration JSON. This file is only produced if you call the publish_hwm method.
If you want prefer file managed hwm, you can edit the location of the hwn by following these instructions Collector Integration General Notes | Storing-High-Water-Marks-(HWM)
Step 8: Push the Extracts to K
Once the files have been validated, you can push the files to the K landing directory.
You can use Azure Storage Explorer if you want to initially do this manually. You can push the files using python as well (see Airflow example below)
Example: Using Airflow to orchestrate the Extract and Push to K
The following example is how you can orchestrate the Tableau collector using Airflow and push the files to K hosted on Azure. The code is not expected to be used as-is but as a template for your own DAG.
# built-in
import os
# Installed
from airflow.operators.python_operator import PythonOperator
from airflow.models.dag import DAG
from airflow.operators.dummy import DummyOperator
from airflow.utils.dates import days_ago
from airflow.utils.task_group import TaskGroup
from plugins.utils.azure_blob_storage import AzureBlobStorage
from kada_collectors.extractors.utils import load_config, get_hwm, publish_hwm, get_generic_logger
from kada_collectors.extractors.tableau import Extractor
# To be configed by the customer.
# Note variables may change if using a different object store.
KADA_SAS_TOKEN = os.getenv("KADA_SAS_TOKEN")
KADA_CONTAINER = ""
KADA_STORAGE_ACCOUNT = ""
KADA_LANDING_PATH = "lz/tableau/landing"
KADA_EXTRACTOR_CONFIG = {
"server_address": "http://tabserver",
"username": "user",
"password": "password",
"sites": [],
"db_host": "tabserver",
"db_username": "repo_user",
"db_password": "repo_password",
"db_port": 8060,
"db_name": "workgroup",
"meta_only": False,
"retries": 5,
"dry_run": False,
"output_path": "/set/to/output/path",
"mask": True,
"mapping": {}
}
# To be implemented by the customer.
# Upload to your landing zone storage.
# Change '.csv' to '.csv.gz' if you set compress = true in the config
def upload():
output = KADA_EXTRACTOR_CONFIG['output_path']
for filename in os.listdir(output):
if filename.endswith('.csv'):
file_to_upload_path = os.path.join(output, filename)
AzureBlobStorage.upload_file_sas_token(
client=KADA_SAS_TOKEN,
storage_account=KADA_STORAGE_ACCOUNT,
container=KADA_CONTAINER,
blob=f'{KADA_LANDING_PATH}/{filename}',
local_path=file_to_upload_path
)
with DAG(dag_id="taskgroup_example", start_date=days_ago(1)) as dag:
# To be implemented by the customer.
# Retrieve the timestamp from the prior run
start_hwm = 'YYYY-MM-DD HH:mm:SS'
end_hwm = 'YYYY-MM-DD HH:mm:SS' # timestamp now
ext = Extractor(**KADA_EXTRACTOR_CONFIG)
start = DummyOperator(task_id="start")
with TaskGroup("taskgroup_1", tooltip="extract tableau and upload") as extract_upload:
task_1 = PythonOperator(
task_id="extract_tableau",
python_callable=ext.run,
op_kwargs={"start_hwm": start_hwm, "end_hwm": end_hwm},
provide_context=True,
)
task_2 = PythonOperator(
task_id="upload_extracts",
python_callable=upload,
op_kwargs={},
provide_context=True,
)
# To be implemented by the customer.
# Timestamp needs to be saved for next run
task_3 = DummyOperator(task_id='save_hwm')
end = DummyOperator(task_id='end')
start >> extract_upload >> end