Sequence API

In some cases you want to enumerate your resources with an increasing counter or use global sequences for your app needs. Aidbox provides handy access to PostgreSQL sequences through REST API. Values generated by this API are transactional and safe to use in concurrent environment.

Create Sequence

You can create named sequence by posting PGSequence resource. We use explicit naming for sequences, so the id element is required!

create-sequence.yaml
yaml
POST /PGSequence
Accept: text/yaml
Content-Type: text/yaml

id: pt_seq

You can specify other PGSequence attributes:

attr type desc
id ident sequence name; only lower case, digits and \_ are allowed in name
start integer initial sequence value (default 1)
cycle boolean cycle after reaching sequence max/min value
increment integer sequence step (default 1)
maxval integer max value to cycle
minval integer min value to cycle

Get next value

Now you can move sequence forward transactionally and reserve the next value:

yaml
POST /PGSequence/pt_seq
Accept: text/yaml

# response
id: pt_seq
value: 1

Each call will increment the sequence.

You can get a range of values by providing the count parameter in the body.

yaml
POST /PGSequence/pt_seq
Accept: text/yaml
Content-Type: text/yaml

count: 5

# response 200
id: pt_seq
values: [2,3,4,5,6]

Read current value

You can read the current state of sequence without incrementing it with GET /PGSequence/[id]

yaml
GET /PGSequence/pt_seq
Accept: text/yaml

# response 200
id: pt_seq
value: 1

Reset value

You can set the sequence to a specific value by PUT /PGSequence/[id]

yaml
PUT /PGSequence/pt_seq
Accept: text/yaml
Content-Type: text/yaml

value: 30

# response 200
value: 30

This will reset the current sequence value to 30, so next get value operation will return 31:

yaml
POST /PGSequence/pt_seq
Accept: text/yaml

## response 200
value: 31

You can use this endpoint if you want to update or create sequence:

yaml
PUT /PGSequence/pt_seq
Accept: text/yaml
Content-Type: text/yaml

start: 300

# response 201 - created

--- 
PUT /PGSequence/pt_seq
Accept: text/yaml
Content-Type: text/yaml

start: 300

# response 200 - untouched

Destroy Sequence

You can drop the sequence with DELETE /PGSequence/[id]

yaml
DELETE /PGSequence/pt_seq
Accept: text/yaml

# response 200
id: pt_seq
value: 1