Postgres
Creating a data generator for Postgres. You will build a Docker image that will be able to populate data in Postgres for the tables you configure.
Requirements
- 10 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
git clone git@github.com:data-catering/data-caterer-example.git
git clone git@github.com:data-catering/data-caterer-example.git
If you already have a Postgres instance running, you can skip to this step.
Postgres Setup
Next, let's make sure you have an instance of Postgres up and running in your local environment. This will make it easy for us to iterate and check our changes.
cd docker
docker-compose up -d mysql
Permissions
Let's make a new user that has the required permissions needed to push data into the Postgres tables we want.
SQL Permission Statements
GRANT INSERT ON <schema>.<table> TO data_caterer_user;
Following permissions are required when enabling configuration.enableGeneratePlanAndTasks(true) as it will gather
metadata information about tables and columns from the below tables.
SQL Permission Statements
GRANT SELECT ON information_schema.columns TO < user >;
GRANT SELECT ON information_schema.statistics TO < user >;
GRANT SELECT ON information_schema.key_column_usage TO < user >;
Plan Setup
Create a new Java or Scala class.
- Java:
src/main/java/io/github/datacatering/plan/MyPostgresJavaPlan.java - Scala:
src/main/scala/io/github/datacatering/plan/MyPostgresPlan.scala
Make sure your class extends PlanRun.
import io.github.datacatering.datacaterer.java.api.PlanRun;
public class MyPostgresJavaPlan extends PlanRun {
}
import io.github.datacatering.datacaterer.api.PlanRun
class MyPostgresPlan extends PlanRun {
}
This class defines where we need to define all of our configurations for generating data. There are helper variables and methods defined to make it simple and easy to use.
Connection Configuration
Within our class, we can start by defining the connection properties to connect to Postgres.
var accountTask = postgres(
"customer_postgres", //name
"jdbc:postgresql://host.docker.internal:5432/customer", //url
"postgres", //username
"postgres", //password
Map.of() //optional additional connection options
)
Additional options such as SSL configuration, etc can be found here.
val accountTask = postgres(
"customer_postgres", //name
"jdbc:postgresql://host.docker.internal:5432/customer", //url
"postgres", //username
"postgres", //password
Map() //optional additional connection options
)
Additional options such as SSL configuration, etc can be found here.
In application.conf:
jdbc {
customer_postgres {
url = "jdbc:mysql://jdbc:postgresql://host.docker.internal:5432/customer/customer"
user = "postgres"
password = "postgres"
driver = "org.postgresql.Driver"
}
}
Schema
Let's create a task for inserting data into the account.accounts and account.balances tables as
defined underdocker/data/sql/postgres/customer.cql. This table should already be setup for you if you followed this
step.
Trimming the connection details to work with the docker-compose Postgres, we have a base Postgres connection to define
the table and schema required. Let's define each field along with their corresponding data type. You will notice that
the text fields do not have a data type defined. This is because the default data type is StringType which
corresponds to text in Postgres.
{
var accountTask = postgres("customer_postgres", "jdbc:postgresql://host.docker.internal:5432/customer")
.table("account", "accounts")
.schema(
field().name("account_number"),
field().name("amount").type(DoubleType.instance()),
field().name("created_by"),
field().name("created_by_fixed_length"),
field().name("open_timestamp").type(TimestampType.instance()),
field().name("account_status")
);
}
val accountTask = postgres("customer_postgres", "jdbc:postgresql://host.docker.internal:5432/customer")
.table("account", "accounts")
.schema(
field.name("account_number"),
field.name("amount").`type`(DoubleType),
field.name("created_by"),
field.name("created_by_fixed_length"),
field.name("open_timestamp").`type`(TimestampType),
field.name("account_status")
)
Depending on how you want to define the schema, follow the below:
- Manual schema guide
- Automatically detect schema from the data source, you can simply
enable
configuration.enableGeneratePlanAndTasks(true) - Automatically detect schema from a metadata source
Additional Configurations
At the end of data generation, a report gets generated that summarises the actions it performed. We can control the output folder of that report via configurations. We will also enable the unique check to ensure any unique fields will have unique values generated.
var config = configuration()
.generatedReportsFolderPath("/opt/app/data/report")
.enableUniqueCheck(true);
val config = configuration
.generatedReportsFolderPath("/opt/app/data/report")
.enableUniqueCheck(true)
Execute
To tell Data Caterer that we want to run with the configurations along with the accountTask, we have to call execute
. So our full plan run will look like this.
public class MyPostgresJavaPlan extends PlanRun {
{
var accountTask = postgres("customer_postgres", "jdbc:postgresql://host.docker.internal:5432/customer")
.table("account", "accounts")
.schema(
field().name("account_number").regex("ACC[0-9]{8}").primaryKey(true),
field().name("amount").type(DoubleType.instance()).min(1).max(1000),
field().name("created_by").expression("#{Name.name}"),
field().name("created_by_fixed_length").sql("CASE WHEN account_status IN ('open', 'closed') THEN 'eod' ELSE 'event' END"),
field().name("open_timestamp").type(TimestampType.instance()).min(java.sql.Date.valueOf("2022-01-01")),
field().name("account_status").oneOf("open", "closed", "suspended", "pending")
);
var config = configuration()
.generatedReportsFolderPath("/opt/app/data/report")
.enableUniqueCheck(true);
execute(config, accountTask);
}
}
class MyPostgresPlan extends PlanRun {
val accountTask = postgres("customer_postgres", "jdbc:postgresql://host.docker.internal:5432/customer")
.table("account", "accounts")
.schema(
field.name("account_number").primaryKey(true),
field.name("amount").`type`(DoubleType).min(1).max(1000),
field.name("created_by").expression("#{Name.name}"),
field.name("created_by_fixed_length").sql("CASE WHEN account_status IN ('open', 'closed') THEN 'eod' ELSE 'event' END"),
field.name("open_timestamp").`type`(TimestampType).min(java.sql.Date.valueOf("2022-01-01")),
field.name("account_status").oneOf("open", "closed", "suspended", "pending")
)
val config = configuration
.generatedReportsFolderPath("/opt/app/data/report")
.enableUniqueCheck(true)
execute(config, accountTask)
}
Run
Now we can run via the script ./run.sh that is in the top level directory of the data-caterer-example to run the
class we just
created.
./run.sh
#input class MyPostgresJavaPlan or MyPostgresPlan
#after completing
docker exec docker-postgresserver-1 psql -Upostgres -d customer -c "SELECT COUNT(1) FROM account.accounts; SELECT * FROM account.accounts LIMIT 10;"
Your output should look like this.
count
-------
100
(1 row)
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
----+----------------+----------------+---------------------+-------------------------+-----------------+----------------------+--------------------+---------------------+------------------+--------------------+-----------+-------------------------+------------------+---------------
1 | 0499572486 | closed | Stewart Hartmann | eod | 951 | | | | | | | 2023-12-02 12:30:37.602 | |
4 | 0777698075 | closed | Shauna Huels | eod | 225 | | | | | | | 2023-08-07 01:25:32.732 | |
2 | 1011209228 | suspended | Miss Yu Torp | event | 301 | | | | | | | 2024-03-07 08:33:03.031 | |
6 | 0759166208 | closed | Mrs. Alesha Koelpin | eod | 778 | | | | | | | 2024-04-18 13:23:43.861 | |
5 | 1151247273 | closed | Eugenio Corkery | eod | 983 | | | | | | | 2024-05-03 22:44:22.816 | |
7 | 3909668884 | suspended | Deandra Ratke | event | 891 | | | | | | | 2024-05-01 13:11:05.498 | |
8 | 5396749742 | suspended | Grant Moen | event | 46 | | | | | | | 2024-02-22 14:43:31.294 | |
9 | 4269791821 | suspended | Kenton Romaguera | event | 735 | | | | | | | 2024-05-16 16:40:55.781 | |
10 | 6095315531 | closed | Crystle Hintz | eod | 279 | | | | | | | 2024-02-18 07:40:21.088 | |
11 | 6625684008 | open | Miss Edelmira Rath | eod | 200 | | | | | | | 2024-05-12 17:17:55.86 | |
(10 rows)
Also check the HTML report, found at docker/sample/report/index.html, that gets generated to get an overview of what
was executed.
