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  • YUGABYTEDB CORE
    • Quick start
      • 1. Install YugabyteDB
      • 2. Create a local cluster
      • 3. Explore distributed SQL
      • 4. Build an application
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      • JSON support
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        • Async Replication (2+ regions)
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      • Query tuning
        • Introduction
        • Get query statistics using pg_stat_statements
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        • Analyzing queries with EXPLAIN
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        • Diesel ORM
    • Develop
      • Learn app development
        • 1. SQL vs NoSQL
        • 2. Data modeling
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        • 5. Aggregations
        • 6. Batch operations
        • 7. Date and time
        • 8. Strings and text
        • 9. TTL for data expiration
      • Real-world examples
        • E-Commerce app
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      • Explore sample apps
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      • YugabyteDB Voyager
        • Install
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    • Deploy
      • Deployment checklist
      • Manual deployment
        • 1. System configuration
        • 2. Install software
        • 3. Start YB-Masters
        • 4. Start YB-TServers
        • 5. Verify deployment
      • Kubernetes
        • Single-zone
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      • Docker
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      • Multi-DC deployments
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        • Asynchronous replication
        • Read replica clusters
    • Benchmark
      • TPC-C
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      • Scalability
        • Scaling queries
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    • Secure
      • Security checklist
      • Enable authentication
        • Enable users
        • Configure client authentication
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        • Password authentication
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      • Role-based access control
        • Overview
        • Manage users and roles
        • Grant privileges
        • Row-level security
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      • Encryption in transit
        • Create server certificates
        • Enable server-to-server encryption
        • Enable client-to-server encryption
        • Connect to clusters
        • TLS and authentication
      • Encryption at rest
      • Column-level encryption
      • Audit logging
        • Configure audit logging
        • Session-Level Audit Logging
        • Object-Level Audit Logging
      • Vulnerability disclosure policy
    • Manage
      • Backup and restore
        • Export and import
        • Distributed snapshots
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        • Bulk import
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      • Change cluster configuration
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      • Upgrade a deployment
      • Grow cluster
    • Troubleshoot
      • Troubleshooting
      • Cluster level issues
        • YCQL connection issues
        • YEDIS connection Issues
        • Recover tserver/master
        • Replace a failed YB-TServer
        • Replace a failed YB-Master
        • Manual remote bootstrap when a majority of peers fail
        • Recover YB-TServer from crash loop
      • Node level issues
        • Check servers
        • Inspect logs
        • System statistics
        • Disk failure
        • Common error messages
    • Contribute
      • Core database
        • Contribution checklist
        • Build the source
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        • Build the docs
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          • Docs page structure
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        • Style guide
  • YUGABYTEDB ANYWHERE
    • Overview
      • Install
      • Configure
    • Install
      • Prerequisites
      • Prepare the environment
      • Install software
      • Prepare nodes
      • Uninstall software
    • Configure
      • Create admin user
      • Configure cloud providers
      • Configure backup target
      • Configure alerts
    • Create deployments
      • Multi-zone universe
      • Multi-region universe
      • Multi-cloud universe
      • Read replica cluster
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    • Manage deployments
      • Start and stop processes
      • Eliminate an unresponsive node
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      • Enable high availability
      • Edit configuration flags
      • Edit a universe
      • Delete a universe
      • Configure instance tags
      • Upgrade YugabyteDB
      • Migrate to Helm 3
    • Back up universes
      • Configure backup storage
      • Back up universe data
      • Restore universe data
      • Schedule data backups
    • Security
      • Security checklist
      • Configure ports
      • LDAP authentication
      • Authorization
      • Create a KMS configuration
      • Enable encryption at rest
      • Enable encryption in transit
      • Network security
    • Alerts and monitoring
      • Alerts
      • Live Queries dashboard
      • Slow Queries dashboard
    • Troubleshoot
      • Install and upgrade issues
      • Cloud provider configuration issues
      • Universe issues
    • Administer
      • Back up YugabyteDB Anywhere
      • Configure authentication
    • Upgrade
      • Upgrade Kubernetes installation
      • Upgrade using Replicated
  • YUGABYTEDB MANAGED
    • Overview
    • Quick start
      • Create a Sandbox cluster
      • Connect to the cluster
      • Explore distributed SQL
      • Build an application
        • Before you begin
        • Java
        • Go
        • Python
        • Node.js
        • C
        • C++
        • C#
        • Ruby
        • Rust
        • PHP
    • Deploy clusters
      • Plan your cluster
      • Choose a topology
      • VPC network
        • Overview
        • VPCs
        • Peering connections
        • Create a VPC Network
      • Create your cluster
        • Sandbox
        • Single region
        • Replicate across regions
    • Secure clusters
      • IP allow lists
      • Database authorization
      • Add database users
      • Encryption in transit
      • Audit account activity
    • Connect to clusters
      • Cloud Shell
      • Client shell
      • Connect applications
    • Alerts and monitoring
      • Alerts
      • Performance metrics
      • Live queries
      • Slow queries
      • Performance Advisor
      • Cluster activity
    • Manage clusters
      • Scale and configure clusters
      • Backup and restore
      • Maintenance windows
      • Create extensions
    • Administration and billing
      • Manage account access
      • Manage API keys
      • Manage billing
      • Cluster costs
    • Example applications
      • Connect a Spring application
      • Connect a YCQL Java application
      • Hasura Cloud
      • Deploy a GraphQL application
    • Security architecture
      • Security architecture
      • Shared responsibility model
    • Troubleshoot
    • YugabyteDB Managed FAQ
    • What's new
  • INTEGRATIONS
    • Apache Kafka
    • Apache Spark
    • Camunda
    • Debezium
    • Django REST framework
    • Entity Framework
    • Flyway
    • GORM
    • Hasura
      • Application Development
      • Benchmarking
    • JanusGraph
    • KairosDB
    • Liquibase
    • Metabase
    • Presto
    • Prisma
    • Sequelize
    • Spring Framework
      • Spring Data YugabyteDB
      • Spring Data JPA
      • Spring Data Cassandra
    • SQLAlchemy
    • WSO2 Identity Server
    • YSQL Loader
    • YugabyteDB JDBC driver
  • REFERENCE
    • Architecture
      • Design goals
      • Key concepts
        • Universe
        • YB-TServer Service
        • YB-Master Service
      • Core functions
        • Universe creation
        • Table creation
        • Write IO path
        • Read IO path
        • High availability
      • Layered architecture
      • Query layer
        • Overview
      • DocDB transactions layer
        • Transactions overview
        • Transaction isolation levels
        • Explicit locking
        • Read Committed
        • Single-row transactions
        • Distributed transactions
        • Transactional IO path
      • DocDB sharding layer
        • Hash & range sharding
        • Tablet splitting
        • Colocated tables
      • DocDB replication layer
        • Replication
        • xCluster replication
        • Read replicas
        • Change data capture (CDC)
      • DocDB storage layer
        • Persistence
        • Performance
    • APIs
      • YSQL
        • The SQL language
          • SQL statements
            • ABORT
            • ALTER DATABASE
            • ALTER DEFAULT PRIVILEGES
            • ALTER DOMAIN
            • ALTER FOREIGN DATA WRAPPER
            • ALTER FOREIGN TABLE
            • ALTER GROUP
            • ALTER POLICY
            • ALTER ROLE
            • ALTER SEQUENCE
            • ALTER SERVER
            • ALTER TABLE
            • ALTER USER
            • ANALYZE
            • BEGIN
            • CALL
            • COMMENT
            • COMMIT
            • COPY
            • CREATE AGGREGATE
            • CREATE CAST
            • CREATE DATABASE
            • CREATE DOMAIN
            • CREATE EXTENSION
            • CREATE FOREIGN DATA WRAPPER
            • CREATE FOREIGN TABLE
            • CREATE FUNCTION
            • CREATE GROUP
            • CREATE INDEX
            • CREATE MATERIALIZED VIEW
            • CREATE OPERATOR
            • CREATE OPERATOR CLASS
            • CREATE POLICY
            • CREATE PROCEDURE
            • CREATE ROLE
            • CREATE RULE
            • CREATE SCHEMA
            • CREATE SEQUENCE
            • CREATE SERVER
            • CREATE TABLE
            • CREATE TABLE AS
            • CREATE TRIGGER
            • CREATE TYPE
            • CREATE USER
            • CREATE USER MAPPING
            • CREATE VIEW
            • DEALLOCATE
            • DELETE
            • DO
            • DROP AGGREGATE
            • DROP CAST
            • DROP DATABASE
            • DROP DOMAIN
            • DROP EXTENSION
            • DROP FOREIGN DATA WRAPPER
            • DROP FOREIGN TABLE
            • DROP FUNCTION
            • DROP GROUP
            • DROP MATERIALIZED VIEW
            • DROP OPERATOR
            • DROP OPERATOR CLASS
            • DROP OWNED
            • DROP POLICY
            • DROP PROCEDURE
            • DROP ROLE
            • DROP RULE
            • DROP SEQUENCE
            • DROP SERVER
            • DROP TABLE
            • DROP TRIGGER
            • DROP TYPE
            • DROP USER
            • END
            • EXECUTE
            • EXPLAIN
            • GRANT
            • IMPORT FOREIGN SCHEMA
            • INSERT
            • LOCK
            • PREPARE
            • REASSIGN OWNED
            • REFRESH MATERIALIZED VIEW
            • RELEASE SAVEPOINT
            • RESET
            • REVOKE
            • ROLLBACK
            • ROLLBACK TO SAVEPOINT
            • SAVEPOINT
            • SELECT
            • SET
            • SET CONSTRAINTS
            • SET ROLE
            • SET SESSION AUTHORIZATION
            • SET TRANSACTION
            • SHOW
            • SHOW TRANSACTION
            • TRUNCATE
            • UPDATE
            • VALUES
          • WITH clause
            • WITH clause—SQL syntax and semantics
            • recursive CTE
            • case study—traversing an employee hierarchy
            • traversing general graphs
              • graph representation
              • common code
              • undirected cyclic graph
              • directed cyclic graph
              • directed acyclic graph
              • rooted tree
              • Unique containing paths
              • Stress testing find_paths()
            • case study—Bacon Numbers from IMDb
              • Bacon numbers for synthetic data
              • Bacon numbers for IMDb data
        • Data types
          • Array
            • array[] constructor
            • Literals
              • Text typecasting and literals
              • Array of primitive values
              • Row
              • Array of rows
            • FOREACH loop (PL/pgSQL)
            • array of DOMAINs
            • Functions and operators
              • ANY and ALL
              • Array comparison
              • Array slice operator
              • Array concatenation
              • Array properties
              • array_agg(), unnest(), generate_subscripts()
              • array_fill()
              • array_position(), array_positions()
              • array_remove()
              • array_replace() / set value
              • array_to_string()
              • string_to_array()
          • Binary
          • Boolean
          • Character
          • Date and time
            • Conceptual background
            • Timezones and UTC offsets
              • Catalog views
              • Extended_timezone_names
                • Unrestricted full projection
                • Real timezones with DST
                • Real timezones no DST
                • Synthetic timezones no DST
              • Offset/timezone-sensitive operations
                • Timestamptz to/from timestamp conversion
                • Pure 'day' interval arithmetic
              • Four ways to specify offset
                • Name-resolution rules
                  • 1 case-insensitive resolution
                  • 2 ~names.abbrev never searched
                  • 3 'set timezone' string not resolved in ~abbrevs.abbrev
                  • 4 ~abbrevs.abbrev before ~names.name
                  • Helper functions
              • Syntax contexts for offset
              • Recommended practice
            • Typecasting between date-time and text-values
            • Semantics of the date-time data types
              • Date data type
              • Time data type
              • Plain timestamp and timestamptz
              • Interval data type
                • Interval representation
                  • Ad hoc examples
                  • Representation model
                • Interval value limits
                • Declaring intervals
                • Justify() and extract(epoch...)
                • Interval arithmetic
                  • Interval-interval comparison
                  • Interval-interval addition and subtraction
                  • Interval-number multiplication
                  • Moment-moment overloads of "-"
                  • Moment-interval overloads of "+" and "-"
                • Custom interval domains
                • Interval utility functions
            • Typecasting between date-time datatypes
            • Operators
              • Test comparison overloads
              • Test addition overloads
              • Test subtraction overloads
              • Test multiplication overloads
              • Test division overloads
            • General-purpose functions
              • Creating date-time values
              • Manipulating date-time values
              • Current date-time moment
              • Delaying execution
              • Miscellaneous
                • Function age()
                • Function extract() | date_part()
                • Implementations that model the overlaps operator
            • Formatting functions
            • Case study—SQL stopwatch
            • Download & install the date-time utilities
            • ToC
          • JSON
            • JSON literals
            • Primitive and compound data types
            • Code example conventions
            • Indexes and check constraints
            • Functions & operators
              • ::jsonb, ::json, ::text (typecast)
              • ->, ->>, #>, #>> (JSON subvalues)
              • - and #- (remove)
              • || (concatenation)
              • = (equality)
              • @> and <@ (containment)
              • ? and ?| and ?& (key or value existence)
              • array_to_json()
              • jsonb_agg()
              • jsonb_array_elements()
              • jsonb_array_elements_text()
              • jsonb_array_length()
              • jsonb_build_object()
              • jsonb_build_array()
              • jsonb_each()
              • jsonb_each_text()
              • jsonb_extract_path()
              • jsonb_extract_path_text() and json_extract_path_text()
              • jsonb_object()
              • jsonb_object_agg()
              • jsonb_object_keys()
              • jsonb_populate_record()
              • jsonb_populate_recordset()
              • jsonb_pretty()
              • jsonb_set() and jsonb_insert()
              • jsonb_strip_nulls()
              • jsonb_to_record()
              • jsonb_to_recordset()
              • jsonb_typeof()
              • row_to_json()
              • to_jsonb()
          • Money
          • Numeric
          • Range
          • Serial
          • UUID
        • Functions and operators
          • Aggregate functions
            • Informal functionality overview
            • Invocation syntax and semantics
            • grouping sets, rollup, cube
            • Per function signature and purpose
              • avg(), count(), max(), min(), sum()
              • array_agg(), string_agg(), jsonb_agg(), jsonb_object_agg()
              • bit_and(), bit_or(), bool_and(), bool_or()
              • variance(), var_pop(), var_samp(), stddev(), stddev_pop(), stddev_samp()
              • linear regression
                • covar_pop(), covar_samp(), corr()
                • regr_%()
              • mode(), percentile_disc(), percentile_cont()
              • rank(), dense_rank(), percent_rank(), cume_dist()
            • case study—percentile_cont() and the "68–95–99.7" rule
            • case study—linear regression on COVID data
              • Download the COVIDcast data
              • Ingest the COVIDcast data
                • Inspect the COVIDcast data
                • Copy the .csv files to staging tables
                • Check staged data conforms to the rules
                • Join the staged data into a single table
                • SQL scripts
                  • Create cr_staging_tables()
                  • Create cr_copy_from_scripts()
                  • Create assert_assumptions_ok()
                  • Create xform_to_covidcast_fb_survey_results()
                  • ingest-the-data.sql
              • Analyze the COVIDcast data
                • symptoms vs mask-wearing by day
                • Data for scatter-plot for 21-Oct-2020
                • Scatter-plot for 21-Oct-2020
                • SQL scripts
                  • analysis-queries.sql
                  • synthetic-data.sql
          • currval()
          • lastval()
          • nextval()
          • setval()
          • Window functions
            • Informal functionality overview
            • Invocation syntax and semantics
            • Per function signature and purpose
              • row_number(), rank() and dense_rank()
              • percent_rank(), cume_dist() and ntile()
              • first_value(), nth_value(), last_value()
              • lag(), lead()
              • Tables for the code examples
                • table t1
                • table t2
                • table t3
                • table t4
            • case study—analyzing a normal distribution
              • Bucket allocation scheme
              • do_clean_start.sql
              • cr_show_t4.sql
              • cr_dp_views.sql
              • cr_int_views.sql
              • cr_pr_cd_equality_report.sql
              • cr_bucket_using_width_bucket.sql
              • cr_bucket_dedicated_code.sql
              • do_assert_bucket_ok
              • cr_histogram.sql
              • cr_do_ntile.sql
              • cr_do_percent_rank.sql
              • cr_do_cume_dist.sql
              • do_populate_results.sql
              • do_report_results.sql
              • do_compare_dp_results.sql
              • do_demo.sql
              • Reports
                • Histogram report
                • dp-results
                • compare-dp-results
                • int-results
          • yb_hash_code()
        • Keywords
        • Reserved names
      • YCQL
        • ALTER KEYSPACE
        • ALTER ROLE
        • ALTER TABLE
        • CREATE INDEX
        • CREATE KEYSPACE
        • CREATE ROLE
        • CREATE TABLE
        • CREATE TYPE
        • DROP INDEX
        • DROP KEYSPACE
        • DROP ROLE
        • DROP TABLE
        • DROP TYPE
        • GRANT PERMISSION
        • GRANT ROLE
        • REVOKE PERMISSION
        • REVOKE ROLE
        • USE
        • INSERT
        • SELECT
        • EXPLAIN
        • UPDATE
        • DELETE
        • TRANSACTION
        • TRUNCATE
        • Simple expressions
        • Subscripted expressions
        • Function call
        • Operators
        • BLOB
        • BOOLEAN
        • Collection
        • FROZEN
        • INET
        • Integer and counter
        • Non-integer
        • TEXT
        • DATE, TIME, and TIMESTAMP
        • UUID and TIMEUUID
        • JSONB
        • Date and time
        • BATCH
    • CLIs
      • yb-ctl
      • yb-docker-ctl
      • ysqlsh
      • ycqlsh
      • yb-admin
      • yb-ts-cli
      • ysql_dump
      • ysql_dumpall
    • Configuration
      • yb-tserver
      • yb-master
      • yugabyted
      • Default ports
    • Drivers and ORMs
      • JDBC Drivers
      • C# Drivers
      • Go Drivers
      • Python Drivers
      • Client drivers for YSQL
      • Client drivers for YCQL
    • Connectors
      • Kafka Connect YugabyteDB
    • Third party tools
      • pgAdmin
      • Apache Superset
      • Arctype
      • DBeaver
      • TablePlus
      • DbSchema
      • SQL Workbench/J
      • Cassandra Workbench
    • Sample datasets
      • Chinook
      • Northwind
      • PgExercises
      • SportsDB
      • Retail Analytics
  • RELEASES
    • Releases overview
      • v2.15 series (preview)
      • v2.13 series
      • v2.12 series (stable)
      • v2.11 series
      • v2.9 series
      • v2.8 series
      • v2.7 series
      • v2.6 series
      • v2.5 series
      • v2.4 series
      • v2.3 series
      • v2.2 series
      • v2.1 series
      • v2.0 series
      • v1.3 series
      • v1.2 series
    • Release versioning
  • FAQ
    • Comparisons
      • Amazon Aurora
      • Google Cloud Spanner
      • CockroachDB
      • TiDB
      • Vitess
      • MongoDB
      • FoundationDB
      • Amazon DynamoDB
      • Azure Cosmos DB
      • Apache Cassandra
      • PostgreSQL
      • Redis in-memory store
      • Apache HBase
    • General FAQ
    • Operations FAQ
    • API compatibility FAQ
    • YugabyteDB Anywhere FAQ
  • MISC
    • YEDIS
      • Quick start
      • Develop
        • Build an application
        • C#
        • C++
        • Go
        • Java
        • NodeJS
        • Python
      • API reference
        • APPEND
        • AUTH
        • CONFIG
        • CREATEDB
        • DELETEDB
        • LISTDB
        • SELECT
        • DEL
        • ECHO
        • EXISTS
        • EXPIRE
        • EXPIREAT
        • FLUSHALL
        • FLUSHDB
        • GET
        • GETRANGE
        • GETSET
        • HDEL
        • HEXISTS
        • HGET
        • HGETALL
        • HINCRBY
        • HKEYS
        • HLEN
        • HMGET
        • HMSET
        • HSET
        • HSTRLEN
        • HVALS
        • INCR
        • INCRBY
        • KEYS
        • MONITOR
        • PEXPIRE
        • PEXPIREAT
        • PTTL
        • ROLE
        • SADD
        • SCARD
        • RENAME
        • SET
        • SETEX
        • PSETEX
        • SETRANGE
        • SISMEMBER
        • SMEMBERS
        • SREM
        • STRLEN
        • ZRANGE
        • TSADD
        • TSCARD
        • TSGET
        • TSLASTN
        • TSRANGEBYTIME
        • TSREM
        • TSREVRANGEBYTIME
        • TTL
        • ZADD
        • ZCARD
        • ZRANGEBYSCORE
        • ZREM
        • ZREVRANGE
        • ZSCORE
        • PUBSUB
        • PUBLISH
        • SUBSCRIBE
        • UNSUBSCRIBE
        • PSUBSCRIBE
        • PUNSUBSCRIBE
    • Legal
      • Third party software
>

Camunda

Report a doc issue Suggest new content Contributor guide
  • Prerequisites
  • Configure Camunda Platform 7
  • Verify the integration
  • Run a hello world application
    • Model the process as BPMN
    • Implement an external task worker
    • Implement the NodeJS script
    • Deploy the process using Camunda Modeler

Camunda is a Java-based framework supporting BPMN (Business Process Modeling Notation) for workflow and process automation, CMMN (Case Management Model and Notation) for Case Management and DMN (Decision Model and Notation) for business decision management.

Camunda supports PostgreSQL as a datasource. Because YugabyteDB is wire compatible with PostgreSQL, it works out of the box with Camunda as a datasource. This document covers how to:

  • Configure Camunda to use YugabyteDB (YSQL) as a data source.
  • Run a small hello world example in Camunda.

Prerequisites

This tutorial assumes that:

  • YugabyteDB is up and running. If you're new to YugabyteDB, you can download, install, and have YugabyteDB up and running in minutes by following the steps in Quick start. Alternatively, you can use YugabyteDB Managed to get a fully managed database-as-a-service (DBaaS) for YugabyteDB.
  • Java JDK 1.8 or later is installed.
  • NodeJS v10 or later is installed.
  • Camunda Platform 7 and Modeler are installed following the instructions on Camunda's quick-start page.

Configure Camunda Platform 7

  1. Locate the spring.datasource section in the following files:

    • camunda-bpm-run-7.17.0/configuration/default.yml
    • camunda-bpm-run-7.17.0/configuration/production.yml
  2. Modify the spring.datasource section that uses standard PostgreSQL JDBC driver. Change the url value to point to the YugabyteDB cluster you started:

    # datasource configuration is required
    spring.datasource:
      url: jdbc:postgresql://localhost:5433/yugabyte
      driver-class-name: org.postgresql.Driver
      username: yugabyte
      password: yugabyte
    
  3. Download the PostgreSQL JDBC driver JAR file and place it in the camunda-bpm-run-7.17.0/configuration/userlib directory.



    Alternatively, you can also use the YugabyteDB JDBC driver to connect Camunda to a YugabyteDB cluster. To do so, modify the spring.datasource section in each file to point to the YugabyteDB cluster you started, and replace the value of driver-class-name with com.yugabyte.Driver.

    # datasource configuration is required
    spring.datasource:
      url: jdbc:yugabytedb://localhost:5433/yugabyte
      driver-class-name: com.yugabyte.Driver
      username: yugabyte
      password: yugabyte
    


    Then, download the YugabyteDB JDBC driver JAR file and place it in the camunda-bpm-run-7.17.0/configuration/userlib directory.


    (Read more about the YugabyteDB JDBC driver on its documentation page.)

  4. Start the Camunda Platform server using ./start.sh on Linux or macOS, or ./start.bat on Windows.

Verify the integration

After the server is started, you'll be able to see a few tables getting created in the database. To verify, do the following:

  1. Login to the database using ./bin/ysqsh
  2. Use \d to see the list of tables.
  3. Verify that a list of tables with the prefix ACT_ are created.

See the Camunda docs for more details regarding the tables created.

Run a hello world application

In this example, taken from the Camunda quick-start, you'll use Camunda Modeler to design and deploy a small BPMN for charging the cards.

You'll need three events:

  • Start event
  • Service event
  • End event

Note that for the service event, you need an external task worker. For that purpose, you'll use NodeJS.

Model the process as BPMN

  1. Start Camunda Modeler.

  2. Click File > New File > BPMN Diagram to create a new BPMN diagram.

  3. Double-click the start event, and name the event "Payment Retrieval Requested".

  4. Create a service event:

    1. Click the start event. From its context menu, select the activity shape (rounded rectangle).

    2. The activity shape appears on the canvas. Drag it to your preferred position, and name the shape "Charge Credit Card".

    3. Click the activity shape, and use the wrench button to change the activity type to Service Task.

  5. Repeat the previous step to add an end event named "Payment Received".

  6. Configure the service task:

    1. Enter payment-retrieval in the ID property field to configure an ID for the process.


      The process engine uses the property ID as an identifier for the executable process; it’s a good practice to set it to a human-readable name.

    2. Enter "Payment Retrieval" in the Name property field.

    3. Ensure that the box next to the Executable property is checked.


      Note: If you don't check this box, the process engine ignores the process definition.

  7. Save the BPMN diagram.

Implement an external task worker

After modeling the process, you can create some business logic. Camunda Platform is built so that you can implement your business logic in different languages. You have the choice which language suits your project best. For this example, you'll use JavaScript (NodeJS).

  1. Create a new NodeJS project:

    mkdir charge-card-worker
    cd ./charge-card-worker
    npm init -y
    
  2. Add the Camunda External Task Client library to your project:

    npm install camunda-external-task-client-js
    npm install -D open
    

Implement the NodeJS script

Next, you'll create a new ExternalTaskClient that subscribes to the charge-card topic.

When the process engine encounters a service task configured to be externally handled, it creates an external task instance on which your handler reacts. The handler in this example uses long polling in the ExternalTaskClient to make the communication more efficient.

  1. Create a new file called worker.js with the following contents:

    const { Client, logger } = require('camunda-external-task-client-js');
    const open = require('open');
    
    // configuration for the Client:
    //  - 'baseUrl': URL to the Process Engine
    //  - 'logger': utility to automatically log important events
    //  - 'asyncResponseTimeout': long polling timeout (then a new request will be issued)
    const config = {
        baseUrl: 'http://localhost:8080/engine-rest',
        use: logger,
        asyncResponseTimeout: 10000
      };
    
    // create a Client instance with custom configuration
    const client = new Client(config);
    
    // susbscribe to the topic: 'charge-card'
    client.subscribe('charge-card', async function({ task, taskService }) {
      // Put your business logic here
    
      // Get a process variable
      const amount = task.variables.get('amount');
      const item = task.variables.get('item');
    
      console.log(`Charging credit card with an amount of ${amount}€ for the item '${item}'...`);
    
    
      // Complete the task
      await taskService.complete(task);
    });
    
  2. Run the NodeJS script you just created:

    node ./worker.js
    

Deploy the process using Camunda Modeler

To deploy the process, do the following:

  1. Click the deploy button in Camunda Modeler, enter the deployment name "Payment Retrieval", and click the Deploy button.


    If you're running Camunda Modeler version 3.0.0 or later, you need to provide the URL of an Endpoint Configuration along with the deployment details. This can be either the root endpoint to the REST API (such as http://localhost:8080/engine-rest) or an exact endpoint to the deployment creation method (such as http://localhost:8080/engine-rest/deployment/create).

    alt text

  2. Use Cockpit to verify the deployment.


    Navigate to http://localhost:8080/camunda/app/cockpit/ and log in with a username and password of demo. Your process called Payment Retrieval should be visible on the dashboard.

  3. Use the Camunda REST API to start a new process instance by sending a POST request:

    curl -H "Content-Type: application/json" \
         -X POST \
         -d '{"variables": {"amount": {"value":555,"type":"integer"}, "item": {"value":"item-xyz"} } }' \
         http://localhost:8080/engine-rest/process-definition/key/payment-retrieval/start
    
  4. You can also make a POST request from another tool, such as Postman, with the following JSON body:

    {
      "variables": {
        "amount": {
          "value":555,
          "type":"integer"
        },
        "item": {
          "value": "item-xyz"
        }
      }
    }
    

In your worker, you should now see the output in your console. You have successfully started and executed your first small process.

  • Prerequisites
  • Configure Camunda Platform 7
  • Verify the integration
  • Run a hello world application
    • Model the process as BPMN
    • Implement an external task worker
    • Implement the NodeJS script
    • Deploy the process using Camunda Modeler
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