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Auto Generate From Data Connection

Info

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Creating a data generator based on only a data connection to Postgres.

Requirements

  • 5 minutes
  • Git
  • Gradle
  • Docker

Get Started

First, we will clone the data-caterer-example repo which will already have the base project setup required.

git clone git@github.com:data-catering/data-caterer-example.git

Plan Setup

Create a new Java or Scala class.

  • Java: src/main/java/io/github/datacatering/plan/MyAdvancedAutomatedJavaPlanRun.java
  • Scala: src/main/scala/io/github/datacatering/plan/MyAdvancedAutomatedPlanRun.scala

Make sure your class extends PlanRun.

import io.github.datacatering.datacaterer.java.api.PlanRun;
...

public class MyAdvancedAutomatedJavaPlanRun extends PlanRun {
    {
        var autoRun = configuration()
                .postgres("my_postgres", "jdbc:postgresql://host.docker.internal:5432/customer")  (1)
                .enableGeneratePlanAndTasks(true)                                                 (2)
                .generatedPlanAndTaskFolderPath("/opt/app/data/generated")                        (3)
                .enableUniqueCheck(true)                                                          (4)
                .generatedReportsFolderPath("/opt/app/data/report");

        execute(autoRun);
    }
}

import io.github.datacatering.datacaterer.api.PlanRun
...

class MyAdvancedAutomatedPlanRun extends PlanRun {

  val autoRun = configuration
    .postgres("my_postgres", "jdbc:postgresql://host.docker.internal:5432/customer")  (1)
    .enableGeneratePlanAndTasks(true)                                                 (2)
    .generatedPlanAndTaskFolderPath("/opt/app/data/generated")                        (3)
    .enableUniqueCheck(true)                                                          (4)
    .generatedReportsFolderPath("/opt/app/data/report")

  execute(configuration = autoRun)
}

In the above code, we note the following:

  1. Data source configuration to a Postgres data source called my_postgres
  2. We have enabled the flag enableGeneratePlanAndTasks which tells Data Caterer to go to my_postgres and generate data for all the tables found under the database customer (which is defined in the connection string).
  3. The config generatedPlanAndTaskFolderPath defines where the metadata that is gathered from my_postgres should be saved at so that we could re-use it later.
  4. enableUniqueCheck is set to true to ensure that generated data is unique based on primary key or foreign key definitions.

Note

Unique check will only ensure generated data is unique. Any existing data in your data source is not taken into account, so generated data may fail to insert depending on the data source restrictions

Postgres Setup

If you don't have your own Postgres up and running, you can set up and run an instance configured in the docker folder via.

cd docker
docker-compose up -d postgres
docker exec docker-postgresserver-1 psql -Upostgres -d customer -c '\dt+ account.*'

This will create the tables found under docker/data/sql/postgres/customer.sql. You can change this file to contain your own tables. We can see there are 4 tables created for us, accounts, balances, transactions and mapping.

Run

Let's try run.

cd ..
./run.sh
#input class MyAdvancedAutomatedJavaPlanRun or MyAdvancedAutomatedPlanRun
#after completing
docker exec docker-postgresserver-1 psql -Upostgres -d customer -c 'select * from account.accounts limit 1;'

It should look something like this.

   id   | account_number  | account_status | created_by | created_by_fixed_length | customer_id_int | customer_id_smallint | customer_id_bigint |   customer_id_decimal    | customer_id_real | customer_id_double | open_date  |     open_timestamp      | last_opened_time |                                                           payload_bytes
--------+-----------------+----------------+------------+-------------------------+-----------------+----------------------+--------------------+--------------------------+------------------+--------------------+------------+-------------------------+------------------+------------------------------------------------------------------------------------------------------------------------------------
 100414 | 5uROOVOUyQUbubN | h3H            | SfA0eZJcTm | CuRw                    |              13 |                   42 |               6041 | 76987.745612542900000000 |         91866.78 |  66400.37433202339 | 2023-03-05 | 2023-08-14 11:33:11.343 | 23:58:01.736     | \x604d315d4547616e6a233050415373317274736f5e682d516132524f3d23233c37463463322f342d34376d597e665d6b3d395b4238284028622b7d6d2b4f5042
(1 row)

The data that gets inserted will follow the foreign keys that are defined within Postgres and also ensure the insertion order is correct.

Also check the HTML report that gets generated under docker/sample/report/index.html. You can see a summary of what was generated along with other metadata.

You can now look to play around with other tables or data sources and auto generate for them.

Additional Topics

Learn From Existing Data

If you have any existing data within your data source, Data Caterer will gather metadata about the existing data to help guide it when generating new data. There are configurations that can help tune the metadata analysis found here.

Filter Out Schema/Tables

As part of your connection definition, you can define any schemas and/or tables your don't want to generate data for. In the example below, it will not generate any data for any tables under the history and audit schemas. Also, any table with the name balances or transactions in any schema will also not have data generated.

var autoRun = configuration()
        .postgres(
              "my_postgres", 
              "jdbc:postgresql://host.docker.internal:5432/customer",
              Map.of(
                  "filterOutSchema", "history, audit",
                  "filterOutTable", "balances, transactions")
              )
        )

val autoRun = configuration
  .postgres(
    "my_postgres",
    "jdbc:postgresql://host.docker.internal:5432/customer",
    Map(
      "filterOutSchema" -> "history, audit",
      "filterOutTable" -> "balances, transactions")
    )
  )

Define record count

You can control the record count per sub data source via numRecordsPerStep.

var autoRun = configuration()
      ...
      .numRecordsPerStep(100)

execute(autoRun)

val autoRun = configuration
  ...
  .numRecordsPerStep(100)

execute(configuration = autoRun)