Schemaless JSON Source Connector for Confluent Platform

Kafka Connect Schemaless JSON Source connector is used to stream JSON files from an SFTP directory. It will not try to convert the JSON records to a schema. The recommended converter to use is the StringConverter.

value.converter=org.apache.kafka.connect.storage.StringConverter

To use this connector, use a connector configuration that specifies the name of this connector class in the connector.class configuration property as shown below:

connector.class=io.confluent.connect.sftp.SftpSchemaLessJsonSourceConnector

JSON Schemaless Source Connector Example

This example follows the same steps as the Quick Start. Review the Quick Start for help running the Confluent Platform and installing the SFTP connector package.

Prerequisites

  1. Generate a JSON dataset using the command below:

    echo $'{"id":1,"first_name":"Roscoe","last_name":"Brentnall","email":"rbrentnall0@mediafire.com","gender":"Male","ip_address":"202.84.142.254","last_login":"2018-02-12T06:26:23Z","account_balance":1450.68,"country":"CZ","favorite_color":"#4eaefa"}\n{"id":2,"first_name":"Gregoire","last_name":"Fentem","email":"gfentem1@nsw.gov.au","gender":"Male","ip_address":"221.159.106.63","last_login":"2015-03-27T00:29:56Z","account_balance":1392.37,"country":"ID","favorite_color":"#e8f686"}' > "json-sftp-source.json"

  2. Create an sftp.properties file with the following contents:

    name=SchemaLessJsonSftp
tasks.max=1
connector.class=io.confluent.connect.sftp.SftpSchemaLessJsonSourceConnector
input.path=/path/to/data
error.path=/path/to/error
finished.path=/path/to/finished
input.file.pattern=json-sftp-source.json
behavior.on.error=IGNORE
sftp.username=username
sftp.password=password
sftp.host=localhost
sftp.port=22
kafka.topic=sftp-schemaless-json-topic
value.converter=org.apache.kafka.connect.storage.StringConverter

  3. Load the SFTP Schemaless JSON Source Connector using the Confluent CLI confluent local services connect connector load command.

    Caution

    You must include a double dash (--) between the connector name and your flag. For more information, see this post.

    confluent local services connect connector load SchemaLessJsonSftp --config sftp.properties

    Important

    The confluent local commands are intended for a single-node development environment and are not suitable for a production environment. The data that are produced are transient and are intended to be temporary. For production-ready workflows, see Install and Upgrade Confluent Platform.

Configuration Properties

Connector-specific configuration properties are described below.

General

kafka.topic

The Kafka topic to write the data to.

  • Importance: HIGH
  • Type: STRING
batch.size

The number of records that should be returned with each batch.

  • Importance: LOW
  • Type: INT
  • Default Value: 1000
empty.poll.wait.ms

The amount of time to wait if a poll returns an empty list of records.

  • Importance: LOW
  • Type: LONG
  • Default Value: 250
  • Validator: [1,…,9223372036854775807]

Connection

sftp.host

Sftp host to connect with.

  • Type: string
  • Default: localhost
  • Importance: high
sftp.port

Port number of SFTP server.

  • Type: int
  • Default: 22
  • Importance: medium
sftp.username

Username for sftp server.

  • Type: string
  • Default: foo
  • Importance: high
sftp.password

Password for sftp server.

  • Type: string
  • Default: pass
  • Importance: high

Security

tls.private.key

Private key that will be used for public-key authentication.

  • Type: password
  • Default: [hidden]
  • Importance: low
tls.public.key

Public key that will be used to decrypt the private key if the given private key is encrypted.

  • Type: password
  • Default: [hidden]
  • Importance: low
tls.passphrase

Passphrase that will be used to decrypt the private key if the given private key is encrypted.

  • Type: password
  • Default: [hidden]
  • Importance: low
tls.pemfile

Path to pemfile.

  • Type: string
  • Default: “”
  • Importance: low

Kerberos

If Kerberos is enabled, the Connector assumes the /etc/krb5.conf file has been correctly configured and points to a KDC which can issue tickets for SFTP. The connector will refresh its TGT when it expires.

To test if the configuration of the krb5.conf file and the keytab was successful, the command kinit -k -t /path/to/user.keytab username may be used. The connector first looks for a cached ticket on the system, if it does not exist it uses the configured keytab and principal. Note that if there is ticket cached on the system that is for a different application, the cache may need to be cleared temporarily when starting the connector.

kerberos.user.principal

The principal to use when connecting to SFTP with Kerberos. The `` sftp.username`` is still required. Format: username@REALM.

  • Type: string
  • Default: “”
  • Importance: low
kerberos.keytab.path

The path to the keytab file for the SFTP connector principal. This keytab file should only be readable by the connector.

  • Type: string
  • Default: “”
  • Importance: low

Proxy

sftp.proxy.url

Proxy url for sftp connection.

  • Type: string
  • Default: “”
  • Importance: low
proxy.username

Proxy username for sftp server if proxy is being used.

  • Type: string
  • Default: null
  • Importance: low
proxy.password

Proxy password for sftp server if proxy is being used.

  • Type: string
  • Default: null
  • Importance: low

Auto topic creation

For more information about Auto topic creation, see Configuring Auto Topic Creation for Source Connectors.

Note

Configuration properties accept regular expressions (regex) that are defined as Java regex.

topic.creation.groups

A list of group aliases that are used to define per-group topic configurations for matching topics. A default group always exists and matches all topics.

  • Type: List of String types
  • Default: empty
  • Possible Values: The values of this property refer to any additional groups. A default group is always defined for topic configurations.
topic.creation.$alias.replication.factor

The replication factor for new topics created by the connector. This value must not be larger than the number of brokers in the Kafka cluster. If this value is larger than the number of Kafka brokers, an error occurs when the connector attempts to create a topic. This is a required property for the default group. This property is optional for any other group defined in topic.creation.groups. Other groups use the Kafka broker default value.

  • Type: int
  • Default: n/a
  • Possible Values: >= 1 for a specific valid value or -1 to use the Kafka broker’s default value.
topic.creation.$alias.partitions

The number of topic partitions created by this connector. This is a required property for the default group. This property is optional for any other group defined in topic.creation.groups. Other groups use the Kafka broker default value.

  • Type: int
  • Default: n/a
  • Possible Values: >= 1 for a specific valid value or -1 to use the Kafka broker’s default value.
topic.creation.$alias.include

A list of strings that represent regular expressions that match topic names. This list is used to include topics with matching values, and apply this group’s specific configuration to the matching topics. $alias applies to any group defined in topic.creation.groups. This property does not apply to the default group.

  • Type: List of String types
  • Default: empty
  • Possible Values: Comma-separated list of exact topic names or regular expressions.
topic.creation.$alias.exclude

A list of strings representing regular expressions that match topic names. This list is used to exclude topics with matching values from getting the group’s specfic configuration. $alias applies to any group defined in topic.creation.groups. This property does not apply to the default group. Note that exclusion rules override any inclusion rules for topics.

  • Type: List of String types
  • Default: empty
  • Possible Values: Comma-separated list of exact topic names or regular expressions.
topic.creation.$alias.${kafkaTopicSpecificConfigName}

Any of the Changing Broker Configurations Dynamically for the version of the Kafka broker where the records will be written. The broker’s topic-level configuration value is used if the configuration is not specified for the rule. $alias applies to the default group as well as any group defined in topic.creation.groups.

  • Type: property values
  • Default: Kafka broker value

File System

input.path

The directory where Kafka Connect reads files that are processed. This directory must exist and be writable by the user running Connect.

  • Importance: HIGH
  • Type: STRING
  • Validator: Absolute path to a sftp directory that exists and is writable.
input.file.pattern

Regular expression to check input file names against. This expression must match the entire filename. The equivalent of Matcher.matches().

  • Importance: HIGH
  • Type: STRING
finished.path

The directory where Connect puts files that are successfully processed. This directory must exist and be writable by the user running Connect.

  • Importance: HIGH
  • Type: STRING
  • Validator: Absolute path to a sftp directory that exists and is writable.
error.path

The directory to place files that have errors. This directory must exist and be writable by the user running Kafka Connect.

  • Importance: HIGH
  • Type: STRING
  • Validator: Absolute path to a sftp directory that exists and is writable.
behavior.on.error

Sets how the connector should behave when error are encountered while processing records. FAIL stops the connector when any error occurs. IGNORE ignores the current file and continues to the next file for processing. LOG after logging the error message, it continues to the next file for processing.

  • Importance: HIGH
  • Type: STRING
  • Default Value: FAIL
  • Validator: Matches: FAIL, IGNORE, LOG
cleanup.policy

Sets how the connector should clean up files that are successfully processed. NONE leaves the files in place. Files left in place may be reprocessed if the connector is restarted. DELETE removes the file from the filesystem. MOVE (the default) moves the file to the finished.path directory.

  • Importance: MEDIUM
  • Type: STRING
  • Default Value: MOVE
  • Validator: Matches: NONE, DELETE, MOVE
file.minimum.age.ms

The amount of time in milliseconds after the file was last written to before the file can be processed.

  • Importance: LOW
  • Type: LONG
  • Default Value: 0
  • Validator: [0,…]
processing.file.extension

Before a file is processed, it is renamed to indicate that it is currently being processed. This setting is appended to the end of the file.

  • Importance: LOW
  • Type: STRING
  • Default Value: .PROCESSING
  • Validator: Matches regex( ^.*..+$ )

Timestamps

timestamp.mode

Determines how the connector sets the timestamp for the ConnectRecord. If set to Field, the timestamp is read from a field in the value. This field cannot be optional and must be a Timestamp. Specify the field in timestamp.field. If set to FILE_TIME, the last time the file was modified is used. If set to PROCESS_TIME (the default), the time the record is read is used.

  • Importance: MEDIUM
  • Type: STRING
  • Default Value: PROCESS_TIME
  • Validator: Matches: FIELD, FILE_TIME, PROCESS_TIME