pytd

pytd provides user-friendly interfaces to Treasure Data's REST APIs, Presto query engine, and Plazma primary storage.

The seamless connection allows your Python code to efficiently read/write a large volume of data from/to Treasure Data. Eventually, pytd makes your day-to-day data analytics work more productive.

Installation

pip install pytd

Usage

• Sample usage on Google Colaboratory

Set your API key and endpoint to the environment variables, TD_API_KEY and TD_API_SERVER, respectively, and create a client instance:

import pytd

client = pytd.Client(database='sample_datasets')
# or, hard-code your API key, endpoint, and/or query engine:
# >>> pytd.Client(apikey='1/XXX', endpoint='https://api.treasuredata.com/', database='sample_datasets', default_engine='presto')

Query in Treasure Data

Issue Presto query and retrieve the result:

client.query('select symbol, count(1) as cnt from nasdaq group by 1 order by 1')
# {'columns': ['symbol', 'cnt'], 'data': [['AAIT', 590], ['AAL', 82], ['AAME', 9252], ..., ['ZUMZ', 2364]]}

In case of Hive:

client.query('select hivemall_version()', engine='hive')
# {'columns': ['_c0'], 'data': [['0.6.0-SNAPSHOT-201901-r01']]} (as of Feb, 2019)

It is also possible to explicitly initialize pytd.Client for Hive:

client_hive = pytd.Client(database='sample_datasets', default_engine='hive')
client_hive.query('select hivemall_version()')

Write data to Treasure Data

Data represented as pandas.DataFrame can be written to Treasure Data as follows:

import pandas as pd

df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 10]})
client.load_table_from_dataframe(df, 'takuti.foo', writer='bulk_import', if_exists='overwrite')

For the writer option, pytd supports three different ways to ingest data to Treasure Data:

1. Bulk Import API: bulk_import (default)
   • Convert data into a CSV file and upload in the batch fashion.
   • Unable to append data into an existing table. Use other writers to append data.
2. Presto INSERT INTO query: insert_into
   • Insert every single row in DataFrame by issuing an INSERT INTO query through the Presto query engine.
   • Recommended only for a small volume of data.
3. td-spark: spark
   • Local customized Spark instance directly writes DataFrame to Treasure Data's primary storage system.

Enabling Spark Writer

Since td-spark gives special access to the main storage system via PySpark, follow the instructions below:

1. Contact support@treasuredata.com to activate the permission to your Treasure Data account.
2. Install pytd with [spark] option if you use the third option:

   pip install pytd[spark]
   

If you want to use existing td-spark JAR file, creating SparkWriter with td_spark_path option would be helpful.

from pytd.writer import SparkWriter

writer = SparkWriter(apikey='1/XXX', endpoint='https://api.treasuredata.com/', td_spark_path='/path/to/td-spark-assembly.jar')
client.load_table_from_dataframe(df, 'mydb.bar', writer=writer, if_exists='overwrite')

DB-API

pytd implements Python Database API Specification v2.0 with the help of prestodb/presto-python-client.

Connect to the API first:

from pytd.dbapi import connect

conn = connect(pytd.Client(database='sample_datasets'))
# or, connect with Hive:
# >>> conn = connect(pytd.Client(database='sample_datasets', default_engine='hive'))

Cursor defined by the specification allows us to flexibly fetch query results from a custom function:

def query(sql, connection):
    cur = connection.cursor()
    cur.execute(sql)
    rows = cur.fetchall()
    columns = [desc[0] for desc in cur.description]
    return {'data': rows, 'columns': columns}

query('select symbol, count(1) as cnt from nasdaq group by 1 order by 1', conn)

Below is an example of generator-based iterative retrieval, just like pandas.DataFrame.iterrows:

def iterrows(sql, connection):
    cur = connection.cursor()
    cur.execute(sql)
    index = 0
    columns = None
    while True:
        row = cur.fetchone()
        if row is None:
            break
        if columns is None:
            columns = [desc[0] for desc in cur.description]
        yield index, dict(zip(columns, row))
        index += 1

for index, row in iterrows('select symbol, count(1) as cnt from nasdaq group by 1 order by 1', conn):
    print(index, row)
# 0 {'cnt': 590, 'symbol': 'AAIT'}
# 1 {'cnt': 82, 'symbol': 'AAL'}
# 2 {'cnt': 9252, 'symbol': 'AAME'}
# 3 {'cnt': 253, 'symbol': 'AAOI'}
# 4 {'cnt': 5980, 'symbol': 'AAON'}
# ...

How to replace pandas-td

pytd offers pandas-td-compatible functions that provide the same functionalities more efficiently. If you are still using pandas-td, we recommend you to switch to pytd as follows.

First, install the package from PyPI:

pip install pytd
# or, `pip install pytd[spark]` if you wish to use `to_td`

Next, make the following modifications on the import statements.

Before:

import pandas_td as td

In [1]: %%load_ext pandas_td.ipython

After:

import pytd.pandas_td as td

In [1]: %%load_ext pytd.pandas_td.ipython

Consequently, all pandas_td code should keep running correctly with pytd. Report an issue from here if you noticed any incompatible behaviors.

Use existing td-spark-assembly.jar file

If you want to use existing td-spark JAR file, creating SparkWriter with td_spark_path option would be helpful. You can pass a writer to connect() function.

import pytd
import pytd.pandas_td as td
import pandas as pd
apikey = '1/XXX'
endpoint = 'https://api.treasuredata.com/'

writer = pytd.writer.SparkWriter(apikey=apikey, endpoint=endpoint, td_spark_path='/path/to/td-spark-assembly.jar')
con = td.connect(apikey=apikey, endpoint=endpoint, writer=writer)

df = pd.DataFrame(data={'col1': [1, 2], 'col2': [3, 10]})
td.to_td(df, 'mydb.buzz', con, if_exists='replace', index=False)

For developers

We use black and isort as a formatter, and flake8 as a linter. Our CI checks format with them.

Note that black requires Python 3.6+ while pytd supports 3.5+, so you must need to have Python 3.6+ for development.

We highly recommend you to introduce pre-commit to ensure your commit follows required format.

You can install pre-commit as follows:

pip install pre-commit
pre-commit install

Now, black, isort, and flake8 will check each time you commit changes. You can skip these check with git commit --no-verify.

If you want to check code format manually, you can install them as follows:

pip install black isort flake8

Then, you can run those tool manually;

black pytd
flake8 pytd
isort

You can run formatter, linter, and test by using nox as the following:

pip install nox # You should install at the first time
nox