Sequence Generator REST Service

This Spring Boot application uses Reactor framework to generate unique sequence numbers in concurrent environments.

This service can be used to generate customer, invoice, case numbers, etc. You can control the starting number and the format for each sequence.

In Grails applications you can use the plugin Restful Sequence Number Generator as a client. The Grails client will communicate with this service to get unique sequence numbers.

Why not use database sequences?

Although database sequences are fast they put restrictions on data types (i.e. require numbers). This service lets you use formatted sequence numbers, for example TICKET-1234 and you can also change the sequence number programatically. You could for example reset the sequence to start with YYYY0001 on the first of January every year.

Configuration

application.properties

    server.port=8082

    spring.datasource.url=jdbc:mysql://localhost/sequence_db
    spring.datasource.username=dbuser
    spring.datasource.password=dbpasswd
    spring.datasource.driverClassName=com.mysql.jdbc.Driver
    spring.jpa.hibernate.ddl-auto=update

    sequence.user.password=password
    sequence.admin.password=password

Running

./gradlew bootRun

Initializing

Create a new sequence

The following request creates a new sequence called Customer that will start at 1001 and return numbers formatted as 01001.

curl --user admin:password -H "Accept: application/json" -H "Content-Type: application/json" -X POST -d '{"number":1001, "format":"%05d"}' http://localhost:8082/api/sequence/1/Customer

Get next number

The following three requests returns number 01001, 01002 and 01003.

curl -u user:password  http://localhost:8082/api/sequence/1/Customer/next
{ "number": "01001" }

curl -u user:password  http://localhost:8082/api/sequence/1/Customer/next
{ "number": "01002" }

curl -u user:password  http://localhost:8082/api/sequence/1/Customer/next
{ "number": "01003" }

Get status of a sequence

The following request returns the status of the Customer sequence without increasing the number.

curl -u user:password  http://localhost:8082/api/sequence/1/Customer
{
  "timestamp" : 1404149733472,
  "name" : "Customer",
  "format" : "%05d",
  "number" : 1004
}

Update a sequence

The following request updates an existing sequence called Customer so that the next number will be 5000. To reduce concurrency issues you must specify the current number AND the new number. If the current sequence number is not equal to the specified number, the update will not be applied.

curl --user admin:password -H "Accept: application/json" -H "Content-Type: application/json" -X PUT -d '{"current":1004, "number":5000}' http://localhost:8082/api/sequence/1/Customer

curl -u user:password  http://localhost:8082/api/sequence/1/Customer/next
{ "number": "05000" }

Delete a sequence

The following request deletes an existing sequence called Customer.

curl --user admin:password -H "Accept: application/json" -H "Content-Type: application/json" -X DELETE -d '{}' http://localhost:8082/api/sequence/1/Customer

curl -u user:password  http://localhost:8082/api/sequence/1/Customer
404 NOT FOUND

technipelago/sequence-rest-service