Sqoop Config as Top Level Entity

Title : Sqoop Config Input as a Top Level Entity 

JIRA: https://issues.apache.org/jira/browse/SQOOP-1516

Summary

The current proposal enhances existing functionality ( command line and rest apis)  to support RU ( Read and Update) operations on the config input objects independently.  

Configs are exposed in code via the Connectors and Drivers ( the two CONFIGURABLES supported). They annotate the config classes with "@Config" annotation and that is how sqoop registers these entities into the repository during the server startup. If a connector exists in the sqoop repository (during server-start up or while invoking UpgradeTool) then the connector's upgrade API is invoked to update the attributes of the config object.

The current SQ_CONFIG stores the top level config entries per configurable. 

  +-------------------------------------+
     | SQ_CONFIG                           |
     +-------------------------------------+
     | SQ_CFG_ID: BIGINT PK AUTO-GEN       |
     | SQ_CONFIGURABLE: BIGINT             |FK SQ_CONFIGURABLE(SQC_ID)
     | SQ_CFG_NAME: VARCHAR(64)            |
     | SQ_CFG_TYPE: VARCHAR(32)            |"LINK"|"JOB"
     | SQ_CFG_INDEX: SMALLINT              |
     +-------------------------------------+
 

Currently we support 2 types of configs. LINK and JOB configs. The MConfigType Enum encapsulates this information. It is the value used in "SQ_CFG_TYPE" when a config is registered.

@InterfaceAudience.Private
@InterfaceStability.Unstable
public enum MConfigType {
  /** Unknown config type */
  OTHER,
  @Deprecated
  // NOTE: only exists to support the connector data upgrade path
  CONNECTION,
  /** link config type */
  LINK,
  /** Job config type */
  JOB;
}

Each class annotated with @Config, exposes a list of inputs via the "@Input" annotation and its attributes. The @Input annotated fields are stored in another table SQ_INPUT along with supported attribute and their values. The SQ_INPUT only stores the input keys and the attribute values. The actual value for the SQ_INPUT are dependent on per JOB and per LINK ( Refer to this wiki to understand sqoop entities ) and hence there are 2 additional tables where we store the SQ_JOB_INPUT and SQ_LINK_INPUT.

     +----------------------------+
     | SQ_INPUT                   |
     +----------------------------+
     | SQI_ID: BIGINT PK AUTO-GEN |
     | SQI_NAME: VARCHAR(64)      |
     | SQI_CONFIG: BIGINT         |FK SQ_CONFIG(SQ_CFG_ID)
     | SQI_INDEX: SMALLINT        |
     | SQI_TYPE: VARCHAR(32)      |"STRING"|"MAP"
     | SQI_STRMASK: BOOLEAN       |
     | SQI_STRLENGTH: SMALLINT    |
     | SQI_ENUMVALS: VARCHAR(100) |
     +----------------------------+
 
   +----------------------------+
     | SQ_LINK_INPUT              |
     +----------------------------+
     | SQ_LNKI_LINK: BIGINT PK    | FK SQ_LINK(SQ_LNK_ID)
     | SQ_LNKI_INPUT: BIGINT PK   | FK SQ_INPUT(SQI_ID)
     | SQ_LNKI_VALUE: LONG VARCHAR|
     +----------------------------+
     +----------------------------+
     | SQ_JOB_INPUT               |
     +----------------------------+
     | SQBI_JOB: BIGINT PK        | FK SQ_JOB(SQB_ID)
     | SQBI_INPUT: BIGINT PK      | FK SQ_INPUT(SQI_ID)
     | SQBI_VALUE: LONG VARCHAR   |
     +----------------------------+


 

The following table lists the type and number in (*) of configs exposed by each of the configurables. Each config object is represented as a list. Hence a connector can expose a FROM-CONFIG with more than one config object in it. 

Terminology

Configuration : It refers to a class  in sqoop annotated with @ConfigurationClass and represents a grouping of related configs that the corresponding configurable that owns this configuration class exposes

Here is the code example. 

@ConfigurationClass
public class FromJobConfiguration {
  @Config public FromJobConfig fromJobConfig;
  @Config public IncrementalExtractConfig incrementalExtractConfig;
  public FromJobConfiguration() {
    fromJobConfig = new FromJobConfig();
    incrementalExtractConfig = new IncrementalExtractConfig();
  }
}

Config or ConfigInputs  : They both mean the same in this wiki and are used interchangeably, i.e they represent a class in sqoop that are annotated with the @ConfigClass annotation and used in the @ConfigurationClass annotated class with @Config annotation

@ConfigClass
public class IncrementalExtractConfig {
  @Input(size = 50, editable = InputEditable.USER_ONLY)
  public String key;
  // Optional tells the type of the key, if it s long, int, date, timestamp etc
  @Input
  public String dataType;
  @Input(size = 50, editable = InputEditable.USER_ONLY, overrides = "lastReadValue")
  public String value;
  @Input(editable = InputEditable.CONNECTOR_ONLY)
  public long lastReadValue;
}

Inputs  : They are represented by the @Input annotation on a variable inside a class annotated with @ConfigClass. 

  @Input(size = 50, editable = InputEditable.USER_ONLY, overrides = "lastReadValue")
  public String value;
  @Input(editable = InputEditable.CONNECTOR_ONLY)
  public long lastReadValue;

Requirements

• Configs should be treated as a top level entity as they become more sophisticated with the SQOOP-1804 and in future with the implementation of SQOOP-1643. Currently editing and reading config/ config inputs can only happen via a job or link. This proposal aims at making the config objects as first class citizens, so they can be read and edited by their unique name.
• Config objects per MConfigType (i,e JOB and LINK)  are lists. So ability to edit per "CONFIG" name  is easier than having to edit per "CONFIG LIST" associated with the type. Users do see the names when they list the configs per connector, we can also have a shell command/ rest-API to list all the configs per configurable to make it easier for users to reference configs by name
• Read  the Config Inputs by Type/SubType and By Job /Submission ( since SQOOP-2025 we may be able to have configs by submissionId)
• Update the Config Inputs by Type/SubType for the latest/last submission in the job. We should not allow editing previous submissions and it should be read only
• Only the "inputs" with attribute "USER-ONLY" or "ANY" as per SQOOP-1804 will be editable. Make sure to validate the condition of editable and adhere to cascading changes depending on the overrides attribute on each input.
• Once the input values are edited, the new values will be used in the next job run, unless we maintain history as per SQOOP-2025.

NOTE : Support all the above in both shell command and Rest-API.

Non Goals

• Supporting CD ( create / delete ) of Config Inputs via the REST or command line. It is only allowed via the configurable code and supported annotations on the classes today and it should remain so.
• Editing submission history 

Design and Implementation Details

Here are some details I considered when coming up with the subType and why it made sense.

 

At one point, I thought why not have direction as a parameter for type, JOB, but direction is not relevant to all configurables. i,e if for the driver configs, "direction" has no meaning. Similarly for the type "LINK" there is no concept of direction.

Hence I went with the subType, where subType is a second level hierarchy for distinguishing the types of configs that are supported in sqoop

Alternatives are possible, but we have to bear in mind that config/ config inputs are not associated with jobs and links,  They are associated with connectors/driver ( i,e configurables )

The config input values are associated with jobs and links rather, so when reading/ editing the config input values, either we can use JOB/ LINK entities  or rely more on the "CONFIGTYPE" enum, if we want to treat config as a first class citizen

SubType for MConfigType

SubTypes have been added to the MConfigType Enum to indicate the sub types

/**
 * Represents the various config types supported by the system.
 */
@InterfaceAudience.Private
@InterfaceStability.Unstable
public enum MConfigType {
  /** Unknown config type */
  OTHER,
  @Deprecated
  // NOTE: only exists to support the connector data upgrade path
  CONNECTION,
  /** link config type */
  LINK("link"),
  /** Job config type */
  JOB("from", "to", "driver");
  
  private List<String> subType;
  
  MConfigType(String... aliases){
    this.subType = Arrays.asList(aliases);
  }
  
  List<String> getSubTypes(MConfigType type) {
    return type.subType;
  } 
}

Shell Commands

NOTE: all the job config inputs values are for the last job run only since we do not store the config values for each submission yet

1. show config foo --type JOB --subType from --id 1 
  //*. show config "foo" --type JOB --subType "from" --sid 1 ( SINCE we are not doing SQOOP-2025, this will not be in the current patch) 
 
2. show config foo --type JOB --subType to --id 1 
 
3. show config foo --type JOB --subType driver --id 1
 
4. show config foo --type LINK --subType link --id 1   
 
//  planned, SQOOP-2046 as a sub ticket of SQOOP-1516
5. show input "foo" --config bar --type LINK --id 1 // id here refers to the link id    

Edit Config By Type and Job

NOTE:  Prev submissions cannot be edited, hence we restrict editing to the last job run only)

1. edit config foo --type JOB --subType from --id 1 // id here refers to the job id 
 
// planned, SQOOP-2046 as a sub ticket of SQOOP-1516
2. edit input foo --config bar --type LINK --id 1 // id here refers to the link id
 

Rest API changes

Read Config By Type and Job or Submission

GET v1/config/JOB?name=?&Id=?&subType=   
 
or   
 
GET v1/config?type=JOB&name=?&Id=?&subType=

Edit Config By Type and Job

POST v1/config/LINK?name=?&id=?&subType=  
 
 or 
 
POST v1/config?type=LINK&name=?&id=?&subType=

Repository API changes

Add new API to get config inputs by jobId and type, name

Add new API to edit/post config inputs by jobId and type, name

  public abstract MConfig findFromJobConfig(long jobId, String name);
  public abstract MConfig findToJobConfig(long jobId, String name);
  public abstract MConfig findDriverJobConfig(long jobId, String name);
  public abstract MConfig findLinkConfig(long linkId, String name);
  public abstract void updateFromJobConfig(long jobId, MConfig config);
  public abstract void updateDriverobConfig(long jobId, MConfig config);
  public abstract void updateToJobConfig(long jobId, MConfig config);
  public abstract void updateLinkConfig(long linkId, MConfig config);

Testing

Unit test are almost non existent for the shell code. Hence we will rely on the basic manual testing

Rest APIs can be tested via integration tests and that will be part of the work proposed