Overview

ÐecisionToolkit

build, test & execute decision models

logo

ÐecisionToolkit is a set of tools designed to build, test and evaluate decision models, constructed basing on the Decision Model and Notation (DMN™) specification, which is an industry standard governed by the Object Management Group (OMG®).

ÐecisionToolkit aims to be performant, reliable, and fully compliant with the DMN™ specification, ensuring accurate evaluation of decision models. All tools are implemented in Rust, a programming language known for its security, efficiency and reliability.

ÐecisionToolkit offers a range of features, including DMN models evaluation, decision tables evaluation, and FEEL expressions evaluation. It also includes functionality for parsing, validating, and recognizing DMN models, decision tables, and FEEL expressions. Users can test DMN models, decision tables, and FEEL expressions, and export them to HTML.

Status

ÐecisionToolkit is PRODUCTION READY, although some features may still be refined or changed based on testing and user feedback. We encourage users to try ÐecisionToolkit and share their feedback to help us enhance its usability and performance.

Note

This book assumes you’re using ÐecisionToolkit version 0.3.0 or later. Please visit Installation chapter to learn how to install or update ÐecisionToolkit.

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Installation

ÐecisionToolkit is distributed as a single executable with no external dependencies.

Prebuilt binaries of ÐecisionToolkit can be obtained in the following ways:

Download released version from GitHub releases.
Build and install from source using Cargo.

Download released version

Head to GitHub releases.
Expand the Assets section in selected release version.
Download the binary of your choice, according to the operating system you use.

Tip

Released binary file names contain version number and operating system name like this:
dsntk-0.3.0-linux-x86_64
In order to proceed with the examples presented in this documentation, rename the downloaded binary to the following:

dsntk for Linux and macOS,

dsntk.exe for Windows.

Install using Cargo

Install Cargo and run:

cargo install dsntk

Caution

Installing ÐecisionToolkit using Cargo may require installation of gcc (or a similar C/C++ toolchain like clang), because ÐecisionToolkit relies on math library written in C.

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Getting started

ÐecisionToolkit provides a set of examples ready to play with.

To install examples in examples directory, run:

dsntk exs examples

For more details, refer to Saving examples.

Evaluate example FEEL expression

cd examples/e1

dsntk efe e1.ctx e1.feel

Output:

For more details, refer to Evaluating FEEL expressions.

Evaluate example DMN model

cd examples/e2

dsntk edm e2.ctx e2.dmn -i "Greeting Message"

Output:

"Hello John Doe"

For more details, refer to Evaluating DMN models.

Evaluate example decision table

cd examples/e3

dsntk edt e3.ctx e3.dtb

Output:

0.15

For more details, refer to Evaluating decision tables.

Serve example DMN model

cd examples/e2

dsntk srv -v -H 127.0.0.1 -D .

Output:

Found 1 model.
Loaded 1 model.
Deployed 1 invocable.

Deployed invocables:
  io/dsntk/2_0001/compliance-level-2-test-0001/Greeting%20Message

dsntk 127.0.0.1:22022

Open a new terminal window and run:

curl -s -d "{\"Full Name\":\"John Doe\"}" \
     -H "Content-Type: application/json" \
     -X POST http://127.0.0.1:22022/evaluate/io/dsntk/2_0001/compliance-level-2-test-0001/Greeting%20Message

Output:

{"data":"Hello John Doe"}

For more details, refer to Serving DMN models.

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Command-line

Cheat sheet

Action	Decision model	Decision table	FEEL expression	Built-in examples
Evaluate	edm	edt	efe
Parse	pdm	pdt	pfe
Test	tdm	tdt	tfe
Export	xdm	xdt	xfe
Serve	srv
Save				exs

Commands

srv

Runs ÐecisionToolkit as a service and serves DMN decision models

To display all available options of the srv command, run:

dsntk help srv

For more details, refer to Serving DMN models.

edm

Evaluates DMN decision model

To display all available options of the edm command, run:

dsntk help edm

For more details, refer to Evaluating DMN models.

edt

Evaluates decision table

To display all available options of the edt command, run:

dsntk help edt

For more details, refer to Evaluating decision tables.

efe

Evaluates FEEL expression

To display all available options of the efe command, run:

dsntk help efe

For more details, refer to Evaluating FEEL expressions.

pdm

Parses DMN model

To display all available options of the pdm command, run:

dsntk help pdm

For more details, refer to Parsing DMN models.

pdt

Parses decision table

To display all available options of the pdt command, run:

dsntk help pdt

For more details, refer to Parsing decision tables.

pfe

Parses FEEL expression

To display all available options of the pfe command, run:

dsntk help pfe

For more details, refer to Parsing FEEL expressions.

tdm

Tests DMN model

To display all available options of the tdm command, run:

dsntk help tdm

For more details, refer to Testing DMN models.

tdt

Tests decision table

To display all available options of the tdt command, run:

dsntk help tdt

For more details, refer to Testing decision tables.

tfe

Tests FEEL expression

To display all available options of the tfe command, run:

dsntk help tfe

For more details, refer to Testing FEEL expressions.

xdm

Exports DMN model

To display all available options of the xdm command, run:

dsntk help xdm

For more details, refer to Exporting DMN models.

xdt

Exports decision table

To display all available options of the xdt command, run:

dsntk help xdt

For more details, refer to Exporting decision tables.

xfe

Exports FEEL expression

To display all available options of the xfe command, run:

dsntk help xfe

For more details, refer to Exporting FEEL expressions.

exs

Saves the examples

To display all available options of the exs command, run:

dsntk help exs

For more details, refer to Saving examples.

Options

Below is a list of all ÐecisionToolkit options.

help

Print help:

dsntk --help

or short:

dsntk -h

version

Print version:

dsntk --version

or short:

dsntk -V

Serving DMN models

The core functionality of the ÐecisionToolkit is serving DMN models. The specification precisely defines XML interchange format for decision models. XML files containing decision models are loaded and processed by ÐecisionToolkit server and exposed as a set of JSON API endpoints. Each endpoint represents a single invocable defined in the decision model. Calling an endpoint is equivalent to executing a decision, business knowledge model or decision service.

To explain in details, how to run and use the ÐecisionToolkit server, we assume that the built-in examples are already saved in the ~/examples directory (see Saving examples for details).

Change to the directory containing the examples:

cd ~/examples

Running a server

To start ÐecisionToolkit server, type the following command:

dsntk srv

Expected output should look like this:

Found 1 model.
Loaded 1 model.
Deployed 1 invocable.
dsntk 0.0.0.0:22022

ÐecisionToolkit server is started. By default, ÐecisionToolkit server accepts connections from all available network interfaces 0.0.0.0 and listens on port 22022. During startup, the server scans the current directory with all its subdirectories, and searches for decision models stored as XML files with .dmn extension.

In our example, during directory scanning, the ÐecisionToolkit server has found the dm directory containing one decision model file named dm.dmn. This file was loaded, and one invocable was deployed: decision named Greeting Message.

To stop the ÐecisionToolkit server, press Ctrl+C.

The list of all deployed invocables with endpoint names can be displayed during server startup by specifying the option -v or --verbose, like shown below:

dsntk srv -v

Found 1 model.
Loaded 1 model.
Deployed 1 invocable.

Deployed invocable:
  dm/org/decision-toolkit/greetings/Greeting%20Message

dsntk 0.0.0.0:22022

Evaluating invocables

After starting the ÐecisionToolkit server, the deployed invocable can be evaluated by calling its endpoint with required input data, using e.g. curl tool.

In a new terminal window, run:

curl -s -w '\n' -d '{"Full Name":"Solomon L. Pollack"}' -H "Content-Type: application/json" -X POST http://0.0.0.0:22022/evaluate/dm/org/decision-toolkit/greetings/Greeting%20Message

Expected output:

{"data":"Hello Solomon L. Pollack"}

The ÐecisionToolkit version of a hello world program could look like this:

curl -s -w '\n' -d '{"Full Name":"world"}' -H "Content-Type: application/json" -X POST http://0.0.0.0:22022/evaluate/dm/org/decision-toolkit/greetings/Greeting%20Message

Expected output:

{"data":"Hello world"}

Endpoint names

The JSON API endpoint for evaluating invocables exposed by the ÐecisionToolkit server is named evaluate/.

The full URL of the endpoint is composed of the following parts:

the protocol:

http:// or https://
host address:

0.0.0.0 or 127.0.0.1 or my.domain.com/ alike
endpoint name:

evaluate/
path built from directory names where the file containing the DMN model was found during startup scanning:

dm/
model namespace converted to RDNN-like path:

org/decision-toolkit/
model name:

greetings/
the name of the invocable:

Greeting%20Message

All parts put together give the following URL of the endpoint:

http://127.0.0.1:22022/evaluate/dm/org/decision-toolkit/greetings/Greeting%20Message

While not all characters are legal in URLs, there is %20 between Greeting and Message, which represents a space in percent-encoding. See RFC3986 for more details.

Evaluating DMN models

⏳ Detailed documentation is on the way.

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Evaluating decision tables

⏳ Detailed documentation is on the way.

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Evaluating FEEL expressions

⏳ Detailed documentation is on the way.

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Parsing DMN models

⏳ Detailed documentation is on the way.

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Parsing decision tables

⏳ Detailed documentation is on the way.

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Parsing FEEL expressions

⏳ Detailed documentation is on the way.

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Testing DMN models

⏳ Detailed documentation is on the way.

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Testing decision tables

⏳ Detailed documentation is on the way.

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Testing FEEL expressions

⏳ Detailed documentation is on the way.

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Exporting DMN models

⏳ Detailed documentation is on the way.

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Exporting decision tables

⏳ Detailed documentation is on the way.

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Exporting FEEL expressions

⏳ Detailed documentation is on the way.

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Saving examples

ÐecisionToolkit provides a set of examples ready to play with.

To install the examples in the examples directory, run:

dsntk exs examples

The resulting structure of directories and files should be similar to the one shown below:

tree examples

examples
├── dm
│   ├── dm.ctx
│   └── dm.dmn
├── dt
│   ├── dt.ctx
│   └── dt.dtb
└── fe
    ├── fe.ctx
    └── fe.feel

4 directories, 6 files

FEEL

Arithmetic
Built-in functions

Arithmetic

Addition
Subtraction
Multiplication
Division
Exponentiation
Negation

Addition

1 + 1

a + b

x + y

Subtraction

1 - 1

a - b

x - y

Multiplication

1 * 1

a * b

x * y

Division

1 / 1

a / b

x / y

Exponentiation

2 ** 3

a ** b

x ** y

Negation

- 1

- a

- x

Built-in functions

abs
after
all
any
append
before
ceiling
coincides
concatenate
contains
count
date
date and time
day of week
day of year
decimal
distinct values
duration
during
ends with
even
exp
finished by
finishes
flatten
floor
get entries
get value
includes
index of
insert before
is
list contains
log
lower case
matches
max
mean
meets
median
met by
min
mode
modulo
month of year
not
number
odd
overlaps
overlaps after
overlaps before
product
remove
replace
reverse
sort
split
sqrt
started by
starts
starts with
stddev
string
string length
sublist
substring
substring after
substring before
sum
time
union
upper case
week of year
years and months duration

Containerization

Docker

Dockerfile

FROM scratch

# copy the binary file of Decision Toolkit to container root directory
COPY ./target/x86_64-unknown-linux-musl/release/dsntk /

# copy example DMN model to container root directory
COPY ./dsntk/src/examples/e2/e2.dmn /

# start ÐecisionToolkit as a service and display all deployed invocables
CMD ["/dsntk", "srv", "--verbose"]

docker.sh

#!/usr/bin/env bash

# container name
NAME=dsntk

# container version
VERSION=0.3.0

# stop existing Docker container
docker stop $NAME

# remove stopped Docker container
docker rm $NAME

# remove existing Docker image
docker rmi "$(docker images | grep "^$NAME " | awk '{print $3}')"

# build the Decision Toolkit
cargo +stable build --release --target x86_64-unknown-linux-musl

# build new Docker image
docker build -t $NAME:$VERSION .

# start new Docker container
docker run --name $NAME -d -p 22022:22022 $NAME:$VERSION

# display logs from running Docker container
docker logs -f $NAME

# press Ctrl+C to stop following the log file ;-)

Run command:

./docker.sh

  .
  . (log from executed commands)
  .
Found 1 model.
Loaded 1 model.
Deployed 1 invocable.

Deployed invocables:
  io/dsntk/2_0001/compliance-level-2-test-0001/Greeting%20Message

dsntk 0.0.0.0:22022

Display running containers:

docker ps

result

CONTAINER ID   IMAGE        COMMAND                  CREATED         STATUS         PORTS                     NAMES
fcb45779ce7d   dsntk:0.3.0  "/dsntk srv --verbose"   2 minutes ago   Up 2 minutes   0.0.0.0:22022->22022/tcp  dsntk

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Podman

⏳ Detailed documentation is on the way.

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License

ÐecisionToolkit is licensed under either of

MIT license (see LICENSE-MIT) or
Apache License, Version 2.0 (see LICENSE and NOTICE)

at your option.

Contributing

Any contributions to ÐecisionToolkit are greatly appreciated. All contributions intentionally submitted for inclusion in the work by you, shall be dual licensed, without any additional terms or conditions.

References

DMN

General

Blockchains and Smart Contracts

Development

Versions

This documentation covers version 0.3.0 (or later) of ÐecisionToolkit.

This documentation covers version 1.5 of DMN™ specification.

This documentation version is 0.3.0-rc.0

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