DIS Source Stream
Function
Create a source stream to read data from DIS. DIS accesses user data and Flink job reads data from the DIS stream as input data for jobs. Flink jobs can quickly remove data from producers using DIS source sources for continuous processing. Flink jobs are applicable to scenarios where data outside the cloud service is imported to the cloud service for filtering, real-time analysis, monitoring reports, and dumping.
DIS addresses the challenge of transmitting data outside cloud services to cloud services. DIS builds data intake streams for custom applications capable of processing or analyzing streaming data. DIS continuously captures, transmits, and stores terabytes of data from hundreds of thousands of sources every hour, such as logs, Internet of Things (IoT) data, social media feeds, website clickstreams, and location-tracking events. For more information about DIS, see the .
Syntax
CREATE SOURCE STREAM stream_id (attr_name attr_type (',' attr_name attr_type)* ) WITH ( type = "dis", region = "", channel = "", partition_count = "", encode = "", field_delimiter = "", offset= "");
Keyword
Parameter |
Mandatory |
Description |
---|---|---|
type |
Yes |
Data source type. dis indicates that the data source is DIS. |
region |
Yes |
Region where DIS for storing the data is located. |
ak |
No |
Access Key ID (AK). |
sk |
No |
Specifies the secret access key used together with the ID of the access key. |
channel |
Yes |
Name of the DIS stream where data is located. |
partition_count |
No |
Number of partitions of the DIS stream where data is located. This parameter and partition_range cannot be configured at the same time. If this parameter is not specified, data of all partitions is read by default. |
partition_range |
No |
Range of partitions of a DIS stream, data in which is ingested by the DLI job. This parameter and partition_count cannot be configured at the same time. If this parameter is not specified, data of all partitions is read by default. If you set this parameter to [0:2], data will be read from partitions 1, 2, and 3. |
encode |
Yes |
Data encoding format. The value can be csv, json, xml, email, blob, or user_defined.
|
field_delimiter |
No |
Attribute delimiter. This parameter is mandatory only when the CSV encoding format is used. You can set this parameter, for example, to a comma (,). |
quote |
No |
Quoted symbol in a data format. The attribute delimiters between two quoted symbols are treated as common characters.
NOTE:
|
json_config |
No |
When the encoding format is JSON, you need to use this parameter to specify the mapping between JSON fields and stream definition fields. The format is field1=data_json.field1; field2=data_json.field2; field3=$, where field3=$ indicates that the content of field3 is the entire JSON string. |
xml_config |
No |
If encode is set to xml, you need to set this parameter to specify the mapping between the xml field and the stream definition field. An example of the format is as follows: field1=data_xml.field1; field2=data_xml.field2. |
email_key |
No |
If encode is set to email, you need to set the parameter to specify the information to be extracted. You need to list the key values that correspond to stream definition fields. Multiple key values are separated by commas (,), for example, "Message-ID, Date, Subject, body". There is no keyword in the email body and DLI specifies "body" as the keyword. |
encode_class_name |
No |
If encode is set to user_defined, you need to set this parameter to the name of the user-defined decoding class (including the complete package path). The class must inherit the DeserializationSchema class. |
encode_class_parameter |
No |
If encode is set to user_defined, you can set this parameter to specify the input parameter of the user-defined decoding class. Only one parameter of the string type is supported. |
offset |
No |
|
start_time |
No |
Start time for reading DIS data.
|
enable_checkpoint |
No |
Whether to enable the checkpoint function. The value can be true (enabled) or false (disabled). The default value is false. |
checkpoint_app_name |
No |
ID of a DIS consumer. If a DIS stream is consumed by different jobs, you need to configure the consumer ID for each job to avoid checkpoint confusion. |
checkpoint_interval |
No |
Interval of checkpoint operations on the DIS source operator. The value is in the unit of seconds. The default value is 60. |
Precautions
When creating a source stream, you can specify a time model for subsequent calculation. Currently, DLI supports two time models: Processing Time and Event Time. For details about the syntax, see Configuring Time Models.
Example
- In CSV encoding format, DLI reads data from the DIS stream and records it as codes in CSV format. The codes are separated by commas (,).
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CREATE SOURCE STREAM car_infos ( car_id STRING, car_owner STRING, car_age INT, average_speed INT, total_miles INT, car_timestamp LONG ) WITH ( type = "dis", region = "xxx", channel = "dliinput", encode = "csv", field_delimiter = "," );
- In JSON encoding format, DLI reads data from the DIS stream and records it as codes in JSON format. For example, {"car":{"car_id":"ZJA710XC", "car_owner":"coco", "car_age":5, "average_speed":80, "total_miles":15000, "car_timestamp":1526438880}}
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CREATE SOURCE STREAM car_infos ( car_id STRING, car_owner STRING, car_age INT, average_speed INT, total_miles INT, car_timestamp LONG ) WITH ( type = "dis", region = "xxx", channel = "dliinput", encode = "json", json_config = "car_id=car.car_id;car_owner =car.car_owner;car_age=car.car_age;average_speed =car.average_speed ;total_miles=car.total_miles;" );
- In XML encoding format, DLI reads data from the DIS stream and records it as codes in XML format.
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CREATE SOURCE STREAM person_infos ( pid BIGINT, pname STRING, page int, plocation STRING, pbir DATE, phealthy BOOLEAN, pgrade ARRAY[STRING] ) WITH ( type = "dis", region = "xxx", channel = "dis-dli-input", encode = "xml", field_delimiter = ",", xml_config = "pid=person.pid;page=person.page;pname=person.pname;plocation=person.plocation;pbir=person.pbir;pgrade=person.pgrade;phealthy=person.phealthy" );
An example of XML data is as follows:1 2 3 4 5 6 7 8 9 10 11 12 13
<?xml version="1.0" encoding="utf-8"?> <root> <person> <pid>362305199010025042</pid> <pname>xiaoming</pname> <page>28</page> <plocation>xxx</plocation> <pbir>1990-10-02</pbir> <phealthy>true</phealthy> <pgrade>[A,B,C]</pgrade> </person> </root>
- In EMAIL encoding format, DLI reads data from the DIS stream and records it as a complete Email.
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CREATE SOURCE STREAM email_infos ( Event_ID String, Event_Time Date, Subject String, From_Email String, To_EMAIL String, CC_EMAIL Array[String], BCC_EMAIL String, MessageBody String, Mime_Version String, Content_Type String, charset String, Content_Transfer_Encoding String ) WITH ( type = "dis", region = "xxx", channel = "dliinput", encode = "email", email_key = "Message-ID, Date, Subject, From, To, CC, BCC, Body, Mime-Version, Content-Type, charset, Content_Transfer_Encoding" );
An example of email data is as follows:
Message-ID: <200906291839032504254@sample.com> Date: Fri, 11 May 2001 09:54:00 -0700 (PDT) From: zhangsan@sample.com To: lisi@sample.com, wangwu@sample.com Subject: "Hello World" Cc: lilei@sample.com, hanmei@sample.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Bcc: jack@sample.com, lily@sample.com X-From: Zhang San X-To: Li Si, Wang Wu X-cc: Li Lei, Han Mei X-bcc: X-Folder: \Li_Si_June2001\Notes Folders\Notes inbox X-Origin: Lucy X-FileName: sample.nsf Dear Associate / Analyst Committee: Hello World! Thank you, Associate / Analyst Program zhangsan
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