How to read a list of parquet files from S3 as a pandas dataframe using pyarrow?
Question:
I have a hacky way of achieving this using boto3 (1.4.4), pyarrow (0.4.1) and pandas (0.20.3).
First, I can read a single parquet file locally like this:
import pyarrow.parquet as pq
path = 'parquet/part-r-00000-1e638be4-e31f-498a-a359-47d017a0059c.gz.parquet'
table = pq.read_table(path)
df = table.to_pandas()
I can also read a directory of parquet files locally like this:
import pyarrow.parquet as pq
dataset = pq.ParquetDataset('parquet/')
table = dataset.read()
df = table.to_pandas()
Both work like a charm. Now I want to achieve the same remotely with files stored in a S3 bucket. I was hoping that something like this would work:
dataset = pq.ParquetDataset('s3n://dsn/to/my/bucket')
But it does not:
OSError: Passed non-file path: s3n://dsn/to/my/bucket
After reading pyarrow’s documentation thoroughly, this does not seem possible at the moment. So I came out with the following solution:
Reading a single file from S3 and getting a pandas dataframe:
import io
import boto3
import pyarrow.parquet as pq
buffer = io.BytesIO()
s3 = boto3.resource('s3')
s3_object = s3.Object('bucket-name', 'key/to/parquet/file.gz.parquet')
s3_object.download_fileobj(buffer)
table = pq.read_table(buffer)
df = table.to_pandas()
And here my hacky, not-so-optimized, solution to create a pandas dataframe from a S3 folder path:
import io
import boto3
import pandas as pd
import pyarrow.parquet as pq
bucket_name = 'bucket-name'
def download_s3_parquet_file(s3, bucket, key):
buffer = io.BytesIO()
s3.Object(bucket, key).download_fileobj(buffer)
return buffer
client = boto3.client('s3')
s3 = boto3.resource('s3')
objects_dict = client.list_objects_v2(Bucket=bucket_name, Prefix='my/folder/prefix')
s3_keys = [item['Key'] for item in objects_dict['Contents'] if item['Key'].endswith('.parquet')]
buffers = [download_s3_parquet_file(s3, bucket_name, key) for key in s3_keys]
dfs = [pq.read_table(buffer).to_pandas() for buffer in buffers]
df = pd.concat(dfs, ignore_index=True)
Is there a better way to achieve this? Maybe some kind of connector for pandas using pyarrow? I would like to avoid using pyspark, but if there is no other solution, then I would take it.
Answers:
You can use s3fs from dask which implements a filesystem interface for s3. Then you can use the filesystem argument of ParquetDataset like so:
import s3fs
s3 = s3fs.S3FileSystem()
dataset = pq.ParquetDataset('s3n://dsn/to/my/bucket', filesystem=s3)
You should use the s3fs module as proposed by yjk21. However as result of calling ParquetDataset you’ll get a pyarrow.parquet.ParquetDataset object. To get the Pandas DataFrame you’ll rather want to apply .read_pandas().to_pandas() to it:
import pyarrow.parquet as pq
import s3fs
s3 = s3fs.S3FileSystem()
pandas_dataframe = pq.ParquetDataset('s3://your-bucket/', filesystem=s3).read_pandas().to_pandas()
It can be done using boto3 as well without the use of pyarrow
import boto3
import io
import pandas as pd
# Read the parquet file
buffer = io.BytesIO()
s3 = boto3.resource('s3')
object = s3.Object('bucket_name','key')
object.download_fileobj(buffer)
df = pd.read_parquet(buffer)
print(df.head())
Probably the easiest way to read parquet data on the cloud into dataframes is to use dask.dataframe in this way:
import dask.dataframe as dd
df = dd.read_parquet('s3://bucket/path/to/data-*.parq')
dask.dataframe can read from Google Cloud Storage, Amazon S3, Hadoop file system and more!
Thanks! Your question actually tell me a lot. This is how I do it now with pandas (0.21.1), which will call pyarrow, and boto3 (1.3.1).
import boto3
import io
import pandas as pd
# Read single parquet file from S3
def pd_read_s3_parquet(key, bucket, s3_client=None, **args):
if s3_client is None:
s3_client = boto3.client('s3')
obj = s3_client.get_object(Bucket=bucket, Key=key)
return pd.read_parquet(io.BytesIO(obj['Body'].read()), **args)
# Read multiple parquets from a folder on S3 generated by spark
def pd_read_s3_multiple_parquets(filepath, bucket, s3=None,
s3_client=None, verbose=False, **args):
if not filepath.endswith('/'):
filepath = filepath + '/' # Add '/' to the end
if s3_client is None:
s3_client = boto3.client('s3')
if s3 is None:
s3 = boto3.resource('s3')
s3_keys = [item.key for item in s3.Bucket(bucket).objects.filter(Prefix=filepath)
if item.key.endswith('.parquet')]
if not s3_keys:
print('No parquet found in', bucket, filepath)
elif verbose:
print('Load parquets:')
for p in s3_keys:
print(p)
dfs = [pd_read_s3_parquet(key, bucket=bucket, s3_client=s3_client, **args)
for key in s3_keys]
return pd.concat(dfs, ignore_index=True)
Then you can read multiple parquets under a folder from S3 by
df = pd_read_s3_multiple_parquets('path/to/folder', 'my_bucket')
(One can simplify this code a lot I guess.)
If you are open to also use AWS Data Wrangler.
import awswrangler as wr
df = wr.s3.read_parquet(path="s3://...")
Provided you have the right package setup
$ pip install pandas==1.1.0 pyarrow==1.0.0 s3fs==0.4.2
and your AWS shared config and credentials files configured appropriately
you can use pandas right away:
import pandas as pd
df = pd.read_parquet("s3://bucket/key.parquet")
In case of having multiple AWS profiles you may also need to set
$ export AWS_DEFAULT_PROFILE=profile_under_which_the_bucket_is_accessible
so you can access your bucket.
I have tried the @oya163 solution and it works but after little bit change
import boto3
import io
import pandas as pd
# Read the parquet file
buffer = io.BytesIO()
s3 = boto3.resource('s3',aws_access_key_id='123',aws_secret_access_key= '456')
object = s3.Object('bucket_name','myoutput.parquet')
object.download_fileobj(buffer)
df = pd.read_parquet(buffer)
print(df.head())
I have a hacky way of achieving this using boto3 (1.4.4), pyarrow (0.4.1) and pandas (0.20.3).
First, I can read a single parquet file locally like this:
import pyarrow.parquet as pq
path = 'parquet/part-r-00000-1e638be4-e31f-498a-a359-47d017a0059c.gz.parquet'
table = pq.read_table(path)
df = table.to_pandas()
I can also read a directory of parquet files locally like this:
import pyarrow.parquet as pq
dataset = pq.ParquetDataset('parquet/')
table = dataset.read()
df = table.to_pandas()
Both work like a charm. Now I want to achieve the same remotely with files stored in a S3 bucket. I was hoping that something like this would work:
dataset = pq.ParquetDataset('s3n://dsn/to/my/bucket')
But it does not:
OSError: Passed non-file path: s3n://dsn/to/my/bucket
After reading pyarrow’s documentation thoroughly, this does not seem possible at the moment. So I came out with the following solution:
Reading a single file from S3 and getting a pandas dataframe:
import io
import boto3
import pyarrow.parquet as pq
buffer = io.BytesIO()
s3 = boto3.resource('s3')
s3_object = s3.Object('bucket-name', 'key/to/parquet/file.gz.parquet')
s3_object.download_fileobj(buffer)
table = pq.read_table(buffer)
df = table.to_pandas()
And here my hacky, not-so-optimized, solution to create a pandas dataframe from a S3 folder path:
import io
import boto3
import pandas as pd
import pyarrow.parquet as pq
bucket_name = 'bucket-name'
def download_s3_parquet_file(s3, bucket, key):
buffer = io.BytesIO()
s3.Object(bucket, key).download_fileobj(buffer)
return buffer
client = boto3.client('s3')
s3 = boto3.resource('s3')
objects_dict = client.list_objects_v2(Bucket=bucket_name, Prefix='my/folder/prefix')
s3_keys = [item['Key'] for item in objects_dict['Contents'] if item['Key'].endswith('.parquet')]
buffers = [download_s3_parquet_file(s3, bucket_name, key) for key in s3_keys]
dfs = [pq.read_table(buffer).to_pandas() for buffer in buffers]
df = pd.concat(dfs, ignore_index=True)
Is there a better way to achieve this? Maybe some kind of connector for pandas using pyarrow? I would like to avoid using pyspark, but if there is no other solution, then I would take it.
You can use s3fs from dask which implements a filesystem interface for s3. Then you can use the filesystem argument of ParquetDataset like so:
import s3fs
s3 = s3fs.S3FileSystem()
dataset = pq.ParquetDataset('s3n://dsn/to/my/bucket', filesystem=s3)
You should use the s3fs module as proposed by yjk21. However as result of calling ParquetDataset you’ll get a pyarrow.parquet.ParquetDataset object. To get the Pandas DataFrame you’ll rather want to apply .read_pandas().to_pandas() to it:
import pyarrow.parquet as pq
import s3fs
s3 = s3fs.S3FileSystem()
pandas_dataframe = pq.ParquetDataset('s3://your-bucket/', filesystem=s3).read_pandas().to_pandas()
It can be done using boto3 as well without the use of pyarrow
import boto3
import io
import pandas as pd
# Read the parquet file
buffer = io.BytesIO()
s3 = boto3.resource('s3')
object = s3.Object('bucket_name','key')
object.download_fileobj(buffer)
df = pd.read_parquet(buffer)
print(df.head())
Probably the easiest way to read parquet data on the cloud into dataframes is to use dask.dataframe in this way:
import dask.dataframe as dd
df = dd.read_parquet('s3://bucket/path/to/data-*.parq')
dask.dataframe can read from Google Cloud Storage, Amazon S3, Hadoop file system and more!
Thanks! Your question actually tell me a lot. This is how I do it now with pandas (0.21.1), which will call pyarrow, and boto3 (1.3.1).
import boto3
import io
import pandas as pd
# Read single parquet file from S3
def pd_read_s3_parquet(key, bucket, s3_client=None, **args):
if s3_client is None:
s3_client = boto3.client('s3')
obj = s3_client.get_object(Bucket=bucket, Key=key)
return pd.read_parquet(io.BytesIO(obj['Body'].read()), **args)
# Read multiple parquets from a folder on S3 generated by spark
def pd_read_s3_multiple_parquets(filepath, bucket, s3=None,
s3_client=None, verbose=False, **args):
if not filepath.endswith('/'):
filepath = filepath + '/' # Add '/' to the end
if s3_client is None:
s3_client = boto3.client('s3')
if s3 is None:
s3 = boto3.resource('s3')
s3_keys = [item.key for item in s3.Bucket(bucket).objects.filter(Prefix=filepath)
if item.key.endswith('.parquet')]
if not s3_keys:
print('No parquet found in', bucket, filepath)
elif verbose:
print('Load parquets:')
for p in s3_keys:
print(p)
dfs = [pd_read_s3_parquet(key, bucket=bucket, s3_client=s3_client, **args)
for key in s3_keys]
return pd.concat(dfs, ignore_index=True)
Then you can read multiple parquets under a folder from S3 by
df = pd_read_s3_multiple_parquets('path/to/folder', 'my_bucket')
(One can simplify this code a lot I guess.)
If you are open to also use AWS Data Wrangler.
import awswrangler as wr
df = wr.s3.read_parquet(path="s3://...")
Provided you have the right package setup
$ pip install pandas==1.1.0 pyarrow==1.0.0 s3fs==0.4.2
and your AWS shared config and credentials files configured appropriately
you can use pandas right away:
import pandas as pd
df = pd.read_parquet("s3://bucket/key.parquet")
In case of having multiple AWS profiles you may also need to set
$ export AWS_DEFAULT_PROFILE=profile_under_which_the_bucket_is_accessible
so you can access your bucket.
I have tried the @oya163 solution and it works but after little bit change
import boto3
import io
import pandas as pd
# Read the parquet file
buffer = io.BytesIO()
s3 = boto3.resource('s3',aws_access_key_id='123',aws_secret_access_key= '456')
object = s3.Object('bucket_name','myoutput.parquet')
object.download_fileobj(buffer)
df = pd.read_parquet(buffer)
print(df.head())