Operate API (REST)

Introduction

Operate API is a REST API and provides searching, getting, and changing Operate data. Requests and responses are in JSON notation. Some objects have additional endpoints. For example, process-definitions has an endpoint to get the process-definition as XML representation. In case of errors, Operate API returns an error object.

API documentation as Swagger

A detailed API description is also available as Swagger UI at ${base-url}/swagger-ui.html.

For example: http://localhost:8080/swagger-ui.html

Authentication

You need authentication to access the API endpoints.

Authentication in the cloud

JWT token

To authorize in the cloud using a JWT token, take the steps in the following example:

Example:

1. Obtain a token to access the REST API. You need client_id, client_secret, audience, and the URL of the authorization server. For more information on how to get these for Camunda Platform 8, look at Manage API Clients.

curl -X POST -H 'content-type: application/json' -d '{"client_id": "RgVdPv...", "client_secret":"eDS1~Hg...","audience":"operate.camunda.io","grant_type":"client_credentials"}' https://login.cloud.camunda.io/oauth/token

You will get something like the following:

{
  "access_token": "eyJhbG...",
  "scope": "f408ca38-....",
  "expires_in": 58847,
  "token_type": "Bearer"
}

Take the access_token value from the response object and store it as your token.

2. Send the token as an authorization header in each request. In this case, request all process definitions.

curl -X POST 'http://localhost:8080/v1/process-definitions/search' -H 'Content-Type: application/json' -H 'Authorization: Bearer eyJhb...' -d '{}'

Cookies

Another way to access API is to use cookie headers in each request. The cookie can be obtained by using the API endpoint /api/login. Take the steps in the following example:

Example:

1. Log in as user 'demo' and store the cookie in the file cookie.txt.

curl -c cookie.txt -X POST 'http://localhost:8080/api/login?username=demo&password=demo'

2. Send the cookie (as a header) in each API request. In this case, request all process definitions.

curl -b cookie.txt -X POST 'http://localhost:8080/v1/process-definitions/search' -H 'Content-Type: application/json' -d '{}'

Authentication for Self-Managed cluster

The authentication is described in Operate Configuration - Authentication.

Endpoints

Endpoint (HTTP verb + URL path)	Description	Notes
Process definitions
POST /v1/process-definitions/search	Search for process definitions
GET /v1/process-definitions/{key}	Get process definition by key
GET /v1/process-definitions/{key}/xml	Get process definition by key as XML
Process instances
POST /v1/process-instances/search	Search for process instances	New fields added: flowNodeId Warning 1. New fields could break deserialization, so ignore fields not used.
GET /v1/process-instances/{key}	Get process instance by key	New fields added: flowNodeId Warning 1. New fields could break deserialization, so ignore fields not used.
DELETE /v1/process-instances/{key}	Delete process instance and dependant data by key
Incidents
POST /v1/incidents/search	Search for incidents
GET /v1/incidents/{key}	Get incident by key
Flownode instances
POST /v1/flownode-instances/search	Search for flow node instances
GET /v1/flownode-instances/{key}	Get flow node instance by key
Variables
POST /v1/variables/search	Search for variables; results can contain truncated variable values
GET /v1/variables/{key}	Get variable by key; contains the full value of variable

Search

Every object has a search /v1/<object>/search endpoint which can be requested by POST and a given query request.

Query

The query request consists of components for filter, size, sort, and pagination.

{
   "filter": { object fields to match },
   "size": <number of items to return>,
   "sort": [ {"field":"<name of field to sort on>", "order": "<ASC|DESC>" ],
   "searchAfter": [ <identifier of item from which next search should start> ]
}

Filter

Specifies which fields should match. Only items that match the given fields will be returned. The section on object schemas lists all available fields for each object.

Filter strings, numbers, and booleans

Fields of type string, number, and boolean need the exact value to match.

Examples

Return all items with field processInstanceKey equals 235:

{ "filter": { "processInstanceKey": 235 } }

Return all items with field processInstanceKey equals 235, state equals ACTIVE and incidents equals true:

{
  "filter": { "processInstanceKey": 235, "state": "ACTIVE", "incidents": true }
}

Filter dates

Date fields need to be specified in format: yyyy-MM-dd'T'HH:mm:ss.SSSZZ; for example, 2022-03-17T11:50:25.729+0000.

You can use modifier to match date ranges:

Modifier	Description
||/y	Within a year
||/M	Within a month
||/w	Within a week
||/d	Within a day
||/h	Within an hour
||/m	Within a minute
||/s	Within a second

Example

Return all items with field startDate within a minute (||/m) for 2022-03-17 11:50:25.

{
  "filter": {
    "startDate": "2022-03-17T11:50:25.729+0000||/m"
  }
}

Size

Maximum items should be returned and must be a number.

Example

Return maximum 23 items:

{ "size": 23 }

Sort

Specify which field of the object should be sorted and whether ascending (ASC) or descending (DESC).

Example

Sort by name descending:

{ "sort": [{ "field": "name", "order": "DESC" }] }

Pagination

Specify the item where the next search should start. For this, you need the values from previous results. Copy the values from sortValues field from the previous results into the searchAfter value of query. See also results.

Example

Get next 10 results for previous query by copying the value of sortValues of the previous results object. Assuming the sortValues value was ["the-name",12345], put it as value for searchAfter in the next query.

{
  "sort": [{ "field": "name", "order": "DESC" }],
  "searchAfter": ["the-name", 12345]
}

Query components combined

The query components filter, size, sort, and searchAfter can be combined.

Default values are:

Component	Default value	Description
filter	null	Empty (all fields match)
size	10
sort	[{"field":"key","order":"ASC"}]	Sorted ascending by key
searchAfter	null	First items will be returned

Example

Get max 50 process instances with processVersion equals 2 sorted ascending by bpmnProcessId:

POST /v1/process-instances/search

{
  "filter": {
    "processVersion": 2
  },
  "size": 50,
  "sort": [
    {
      "field": "bpmnProcessId",
      "order": "ASC"
    }
  ]
}

Results are:

  ...
  {
      "key": 2251799813699162,
      "processVersion": 2,
      "bpmnProcessId": "called-process",
      "startDate": "2022-03-17T11:53:41.581+0000",
      "state": "ACTIVE",
      "processDefinitionKey": 2251799813695996
    }
  ],
  "sortValues": [
    "called-process",
    2251799813699162
  ],
  "total": 654
}

Take the value of sortValues and copy it to searchAfter for the next 50 items:

{
  "filter": {
    "processVersion": 2
  },
  "size": 50,
  "sort": [
    {
      "field": "bpmnProcessId",
      "order": "ASC"
    }
  ],
  "searchAfter": ["called-process", 2251799813699162]
}

Results

The API responds with a Results object. It contains an items array, total amount of found items, and sortValues for pagination.

{
  "items": [ { item 1 } , { item 2 } ... ],
  "total": <number of found items>,
  "sortValues": [<array of values to retrieve next page of results>]
}

Items

An array of objects that matches the query.

Total

The total amount of found objects. This is an exact value until 10,000. If more than this, try to make your query more specific.

See also Elasticsearch max results.

sortValues (Pagination)

Use the value (an array) of this field to get the next page of results in your next query. Copy the value to searchAfter in your next query to get the next page.

See also Elasticsearch search after.

Example

Results for process-instances:

{
  "items": [
    {
      "key": 2251799813699213,
      "processVersion": 2,
      "bpmnProcessId": "called-process",
      "startDate": "2022-03-17T11:53:41.758+0000",
      "state": "ACTIVE",
      "processDefinitionKey": 2251799813695996
    },
    {
      "key": 2251799813699262,
      "processVersion": 2,
      "bpmnProcessId": "called-process",
      "startDate": "2022-03-17T11:53:41.853+0000",
      "state": "ACTIVE",
      "processDefinitionKey": 2251799813695996
    }
  ],
  "sortValues": ["called-process", 2251799813699262],
  "total": 654
}

Get object by key

Every object has a GET /v1/<object>/{key} endpoint where {key} is the identifier of the object. Every object has a key field.

Example

Get the data for process instance with key 2251799813699213:

GET /v1/process-instances/2251799813699213

Result:

{
  "key": 2251799813699213,
  "processVersion": 2,
  "bpmnProcessId": "called-process",
  "startDate": "2022-03-17T11:53:41.758+0000",
  "state": "ACTIVE",
  "processDefinitionKey": 2251799813695996
}

Change objects

Some objects can be changed (for example, deleted). The endpoint is the same as getting the object, but with HTTP DELETE instead of HTTP GET. The response is a ChangeStatus object which describes what happened and how many objects were changed.

Example

Delete the data for process instance (and all dependant data) with key 2251799813699213:

DELETE /v1/process-instances/2251799813699213

Result

{
  "message": "1 process instance and dependant data was delete",
  "deleted": 1
}

Object schemas

Each object has a set of fields with values. These values could be of type string, number, boolean, and dateString.

Type	Example
string	"Operate"
number	235
boolean	true	false
dateString	"2022-03-23T11:50:25.729+0000"

Process definition

{
 "key":            <number>
 "name":           <string>
 "version":        <number>
 "bpmnProcessId":  <string>
}

Process instance

{
 "key":                  <number>
 "processVersion":       <number>
 "bpmnProcessId":        <string>
 "parentKey":            <number>
 "startDate":            <dateString: yyyy-MM-dd'T'HH:mm:ss.SSSZZ>
 "endDate":              <dateString: yyyy-MM-dd'T'HH:mm:ss.SSSZZ>
 "state":                <string>
 "processDefinitionKey": <number>
}

Incident

{
 "key":                  <number>
 "processDefinitionKey": <number>
 "processInstanceKey":   <number>
 "type":                 <string>
 "message":              <string>
 "creationTime":         <dateString: yyyy-MM-dd'T'HH:mm:ss.SSSZZ>
 "state":                <string>
}

Flow node instance

{
 "key":                  <number>
 "processInstanceKey":   <number>
 "startDate":            <dateString: yyyy-MM-dd'T'HH:mm:ss.SSSZZ>
 "endDate":              <dateString: yyyy-MM-dd'T'HH:mm:ss.SSSZZ>
 "incidentKey":          <number>
 "type":                 <string>
 "state":                <string>
 "incident":             <boolean>
}

Variable

{
 "key":                 <number>
 "processInstanceKey":  <number>
 "scopeKey":            <number>
 "name":                <string>
 "value":               <string> - Always truncated if value is too big in "search" results. In "get object" result it is not truncated.
 "truncated":           <boolean> - If true 'value' is truncated.
}

Change status

{
 "message": <string> - What was changed
 "deleted": <number> - How many items were deleted
}

Error

{
 "status":       <number> - HTTP Status
 "message":      <string> - Details about the error.
 "instance":     <string> - UUID for look up eg. in log messages
 "type":         <string> - Type of error. Could be ServerException, ClientException, ValidationException, ResourceNotFoundException
}