ObsFile

Obs file sink connector

Key features​

• exactly-once

By default, we use 2PC commit to ensure exactly-once

• file format type

  • text

  • csv

  • parquet

  • orc

  • json

  • excel

Description​

Output data to huawei cloud obs file system.

We made some trade-offs in order to support more file types, so we used the HDFS protocol for internal access to OBS and this connector need some hadoop dependencies. It only supports hadoop version 2.9.X+.

Options​

name	type	required	default	description
path	string	yes	-	The target dir path.
bucket	string	yes	-	The bucket address of obs file system, for example: obs://obs-bucket-name.
access_key	string	yes	-	The access key of obs file system.
access_secret	string	yes	-	The access secret of obs file system.
endpoint	string	yes	-	The endpoint of obs file system.
custom_filename	boolean	no	false	Whether you need custom the filename.
file_name_expression	string	no	"${transactionId}"	Describes the file expression which will be created into the path. Only used when custom_filename is true. Tips
filename_time_format	string	no	"yyyy.MM.dd"	Specify the time format of the path. Only used when custom_filename is true. Tips
file_format_type	string	no	"csv"	Supported file types. Tips
field_delimiter	string	no	'\001'	The separator between columns in a row of data.Only used when file_format is text.
row_delimiter	string	no	"\n"	The separator between rows in a file. Only needed by text file format.
have_partition	boolean	no	false	Whether you need processing partitions.
partition_by	array	no	-	Partition data based on selected fields. Only used then have_partition is true.
partition_dir_expression	string	no	"${k0}=${v0}/${k1}=${v1}/.../${kn}=${vn}/"	Only used then have_partition is true.
is_partition_field_write_in_file	boolean	no	false	Only used then have_partition is true.
sink_columns	array	no		When this parameter is empty, all fields are sink columns.
is_enable_transaction	boolean	no	true
batch_size	int	no	1000000
compress_codec	string	no	none
common-options	object	no	-
max_rows_in_memory	int	no	-	When File Format is Excel,The maximum number of data items that can be cached in the memory.Only used when file_format is excel.
sheet_name	string	no	Sheet${Random number}	Writer the sheet of the workbook. Only used when file_format is excel.

Tips​

file_name_expression ​

Only used when custom_filename is true

file_name_expression describes the file expression which will be created into the path.

We can add the variable ${now} or ${uuid} in the file_name_expression, like test_${uuid}_${now},

${now} represents the current time, and its format can be defined by specifying the option filename_time_format.

Please note that, If is_enable_transaction is true, we will auto add ${transactionId}_ in the head of the file.

filename_time_format ​

Only used when custom_filename is true

When the format in the file_name_expression parameter is xxxx-${now} , filename_time_format can specify the time format of the path, and the default value is yyyy.MM.dd . The commonly used time formats are listed as follows:

Symbol	Description
y	Year
M	Month
d	Day of month
H	Hour in day (0-23)
m	Minute in hour
s	Second in minute

file_format_type ​

We supported as the following file types:

text json csv orc parquet excel

Please note that, The final file name will end with the file_format's suffix, the suffix of the text file is txt.

partition_dir_expression ​

Only used when have_partition is true.

If the partition_by is specified, we will generate the corresponding partition directory based on the partition information, and the final file will be placed in the partition directory.

Default partition_dir_expression is ${k0}=${v0}/${k1}=${v1}/.../${kn}=${vn}/. k0 is the first partition field and v0 is the value of the first partition field.

is_partition_field_write_in_file ​

Only used when have_partition is true.

If is_partition_field_write_in_file is true, the partition field and the value of it will be write into data file.

For example, if you want to write a Hive Data File, Its value should be false.

sink_columns ​

Which columns need be written to file, default value is all the columns get from Transform or Source. The order of the fields determines the order in which the file is actually written.

is_enable_transaction ​

If is_enable_transaction is true, we will ensure that data will not be lost or duplicated when it is written to the target directory.

Please note that, If is_enable_transaction is true, we will auto add ${transactionId}_ in the head of the file. Only support true now.

batch_size ​

The maximum number of rows in a file. For Nexus Engine, the number of lines in the file is determined by batch_size and checkpoint.interval jointly decide. If the value of checkpoint.interval is large enough, sink writer will write rows in a file until the rows in the file larger than batch_size. If checkpoint.interval is small, the sink writer will create a new file when a new checkpoint trigger.

compress_codec ​

The compress codec of files and the details that supported as the following shown:

• txt: lzo none

• json: lzo none

• csv: lzo none

• orc: lzo snappy lz4 zlib none

• parquet: lzo snappy lz4 gzip brotli zstd none

Please note that excel type does not support any compression format

common options ​

Sink plugin common parameters, please refer to Sink Common Options for details.

Task Example​

text file​

For text file format with have_partition and custom_filename and sink_columns

  ObsFile {
    path="/nexus/text"
    bucket = "obs://obs-bucket-name"
    access_key = "xxxxxxxxxxx"
    access_secret = "xxxxxxxxxxx"
    endpoint = "obs.xxxxxx.myhuaweicloud.com"
    file_format_type = "text"
    field_delimiter = "\t"
    row_delimiter = "\n"
    have_partition = true
    partition_by = ["age"]
    partition_dir_expression = "${k0}=${v0}"
    is_partition_field_write_in_file = true
    custom_filename = true
    file_name_expression = "${transactionId}_${now}"
    filename_time_format = "yyyy.MM.dd"
    sink_columns = ["name","age"]
    is_enable_transaction = true
  }

parquet file​

For parquet file format with have_partition and sink_columns

  ObsFile {
    path = "/nexus/parquet"
    bucket = "obs://obs-bucket-name"
    access_key = "xxxxxxxxxxx"
    access_secret = "xxxxxxxxxxxxxxxxx"
    endpoint = "obs.xxxxxx.myhuaweicloud.com"
    have_partition = true
    partition_by = ["age"]
    partition_dir_expression = "${k0}=${v0}"
    is_partition_field_write_in_file = true
    file_format_type = "parquet"
    sink_columns = ["name","age"]
  }

orc file​

For orc file format simple config

  ObsFile {
    path="/nexus/orc"
    bucket = "obs://obs-bucket-name"
    access_key = "xxxxxxxxxxx"
    access_secret = "xxxxxxxxxxx"
    endpoint = "obs.xxxxx.myhuaweicloud.com"
    file_format_type = "orc"
  }

json file​

For json file format simple config

   ObsFile {
       path = "/nexus/json"
       bucket = "obs://obs-bucket-name"
       access_key = "xxxxxxxxxxx"
       access_secret = "xxxxxxxxxxx"
       endpoint = "obs.xxxxx.myhuaweicloud.com"
       file_format_type = "json"
   }

excel file​

For excel file format simple config

   ObsFile {
       path = "/nexus/excel"
       bucket = "obs://obs-bucket-name"
       access_key = "xxxxxxxxxxx"
       access_secret = "xxxxxxxxxxx"
       endpoint = "obs.xxxxx.myhuaweicloud.com"
       file_format_type = "excel"
   }

csv file​

For csv file format simple config

   ObsFile {
       path = "/nexus/csv"
       bucket = "obs://obs-bucket-name"
       access_key = "xxxxxxxxxxx"
       access_secret = "xxxxxxxxxxx"
       endpoint = "obs.xxxxx.myhuaweicloud.com"
       file_format_type = "csv"
   }