HdfsFile

HDFS 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

  • xml

  • binary

• compress codec

  • lzo

Description​

Output data to hdfs file

Supported DataSource Info​

Datasource	Supported Versions
HdfsFile	hadoop 2.x and 3.x

Sink Options​

Name	Type	Required	Default	Description
fs.defaultFS	string	yes	-	The hadoop cluster address that start with hdfs://, for example: hdfs://hadoopcluster
path	string	yes	-	The target dir path is required.
tmp_path	string	yes	/tmp/nexus	The result file will write to a tmp path first and then use mv to submit tmp dir to target dir. Need a hdfs path.
hdfs_site_path	string	no	-	The path of hdfs-site.xml, used to load ha configuration of namenodes
custom_filename	boolean	no	false	Whether you need custom the filename
file_name_expression	string	no	"${transactionId}"	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 ${transactionId}_ in the head of the file.
filename_time_format	string	no	"yyyy.MM.dd"	Only used when custom_filename is true.When the format in the file_name_expression parameter is xxxx-${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:[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	string	no	"csv"	We supported as the following file types:text csv parquet orc json excel xml binary.Please note that, The final file name will end with the file_format's suffix, the suffix of the text file is txt.
field_delimiter	string	no	'\001'	Only used when file_format is text,The separator between columns in a row of data. Only needed by text file format.
row_delimiter	string	no	"\n"	Only used when file_format is text,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	-	Only used then have_partition is true,Partition data based on selected fields.
partition_dir_expression	string	no	"${k0}=${v0}/${k1}=${v1}/.../${kn}=${vn}/"	Only used then 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	boolean	no	false	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	array	no		When this parameter is empty, all fields are sink columns.Which columns need be write to file, default value is all of 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	boolean	no	true	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 ${transactionId}_ in the head of the file.Only support true now.
batch_size	int	no	1000000	The maximum number of rows in a file. For Nexus Engine, the number of lines in the file is determined by batch_size and checkpoint.interval jointly decide. If the value of checkpoint.interval is large enough, sink writer will write rows in a file until the rows in the file larger than batch_size. If checkpoint.interval is small, the sink writer will create a new file when a new checkpoint trigger.
compress_codec	string	no	none	The compress codec of files and the details that supported as the following shown:[txt: lzo none,json: lzo none,csv: lzo none,orc: lzo snappy lz4 zlib none,parquet: lzo snappy lz4 gzip brotli zstd none].Tips: excel type does not support any compression format.
krb5_path	string	no	/etc/krb5.conf	The krb5 path of kerberos
kerberos_principal	string	no	-	The principal of kerberos
kerberos_keytab_path	string	no	-	The keytab path of kerberos
compress_codec	string	no	none	compress codec
common-options	object	no	-	Sink plugin common parameters, please refer to Sink Common Options for details
max_rows_in_memory	int	no	-	Only used when file_format is excel.When File Format is Excel,The maximum number of data items that can be cached in the memory.
sheet_name	string	no	Sheet${Random number}	Only used when file_format is excel.Writer the sheet of the workbook
xml_root_tag	string	no	RECORDS	Only used when file_format is xml, specifies the tag name of the root element within the XML file.
xml_row_tag	string	no	RECORD	Only used when file_format is xml, specifies the tag name of the data rows within the XML file
xml_use_attr_format	boolean	no	-	Only used when file_format is xml, specifies Whether to process data using the tag attribute format.
parquet_avro_write_timestamp_as_int96	boolean	no	false	Only used when file_format is parquet.
parquet_avro_write_fixed_as_int96	array	no	-	Only used when file_format is parquet.
encoding	string	no	"UTF-8"	Only used when file_format_type is json,text,csv,xml.

Task Example​

Simple:​

This example defines a Nexus synchronization task that automatically generates data through FakeSource and sends it to Hdfs.

# Defining the runtime environment
env {
  parallelism = 1
  job.mode = "BATCH"
}

source {
  # This is a example source plugin **only for test and demonstrate the feature source plugin**
  FakeSource {
    parallelism = 1
    result_table_name = "fake"
    row.num = 16
    schema = {
      fields {
        c_map = "map<string, smallint>"
        c_array = "array<int>"
        c_string = string
        c_boolean = boolean
        c_tinyint = tinyint
        c_smallint = smallint
        c_int = int
        c_bigint = bigint
        c_float = float
        c_double = double
        c_decimal = "decimal(30, 8)"
        c_bytes = bytes
        c_date = date
        c_timestamp = timestamp
      }
    }
  }
  # If you would like to get more information about how to configure Nexus and see full list of source plugins,
  # please go to source page
}

transform {
  # If you would like to get more information about how to configure Nexus and see full list of transform plugins,
    # please go to transform page
}

sink {
    HdfsFile {
      fs.defaultFS = "hdfs://hadoopcluster"
      path = "/tmp/hive/warehouse/test2"
      file_format_type = "orc"
    }
  # If you would like to get more information about how to configure Nexus and see full list of sink plugins,
  # please go to sink page
}

For orc file format simple config​

HdfsFile {
    fs.defaultFS = "hdfs://hadoopcluster"
    path = "/tmp/hive/warehouse/test2"
    file_format_type = "orc"
}

For text file format with have_partition and custom_filename and sink_columns​

HdfsFile {
    fs.defaultFS = "hdfs://hadoopcluster"
    path = "/tmp/hive/warehouse/test2"
    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
}

For parquet file format with have_partition and custom_filename and sink_columns​

HdfsFile {
    fs.defaultFS = "hdfs://hadoopcluster"
    path = "/tmp/hive/warehouse/test2"
    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"
    file_format_type = "parquet"
    sink_columns = ["name","age"]
    is_enable_transaction = true
}

For kerberos simple config​

HdfsFile {
    fs.defaultFS = "hdfs://hadoopcluster"
    path = "/tmp/hive/warehouse/test2"
    hdfs_site_path = "/path/to/your/hdfs_site_path"
    kerberos_principal = "[e-mail]"
    kerberos_keytab_path = "/path/to/your/keytab/file.keytab"
}

For compress simple config​

HdfsFile {
    fs.defaultFS = "hdfs://hadoopcluster"
    path = "/tmp/hive/warehouse/test2"
    compress_codec = "lzo"
}