kroki

= image:https://kroki.io/assets/logo.svg[Kroki,200,link={uri-kroki}]
:uri-kroki: https://kroki.io/
:uri-kroki-docs: https://docs.kroki.io/
:uri-maven: https://maven.apache.org/

ifdef::env-github[]
image:https://github.com/yuzutech/kroki/workflows/CI/badge.svg?branch=master[GitHub Actions build status, link=https://github.com/yuzutech/kroki/actions]
image:https://img.shields.io/badge/zulip-join_chat-brightgreen.svg[Zulip chat, link=https://kroki.zulipchat.com/]
endif::[]

{uri-kroki}[Kroki] provides a unified API with support for BlockDiag (BlockDiag, SeqDiag, ActDiag, NwDiag, PacketDiag, RackDiag), BPMN, Bytefield, C4 (with PlantUML), D2, DBML, Diagrams.net (experimental), Ditaa, Erd, Excalidraw, GraphViz, Mermaid, Nomnoml, Pikchr, PlantUML, SvgBob, Symbolator, UMLet, Vega, Vega-Lite, WaveDrom and WireViz... and more to come!

== Quickstart

This section offers a basic tutorial for evaluating Kroki.
More comprehensive installation instructions are in the {uri-kroki-docs}[Kroki documentation].

== Usage

Kroki uses a simple algorithm (deflate + base64) to encode your diagram in the URL:

`GET /plantuml/svg/SyfFKj2rKt3CoKnELR1Io4ZDoSa70000`

You can also call Kroki with `POST`:

 POST /

[source,json]
----
{
  "diagram_source": "Bob -> Alice : hello",
  "diagram_type": "plantuml",
  "output_format": "svg"
}
----

In this case, you don't need to encode your diagram.

It's also possible to send your diagram as plain text using the `Content-Type` header.
The output format will be specified using the `Accept` header and the diagram source will be sent as the request body:

 POST /plantuml

[source]
----
Accept: image/svg+xml
Content-Type: text/plain

Bob -> Alice : hello
----

You can also define the output format in the URL if you don't want to add an `Accept` header:

 POST /plantuml/svg

[source]
----
Content-Type: text/plain

Bob -> Alice : hello
----

The same concept applies when sending the diagram as JSON:

 POST /plantuml/svg
[source,json]
----
{
  "diagram_source": "Bob -> Alice : hello"
}
----

== Project layout

Kroki has a modular architecture:

server::
A Java web server (powered by _Vert.x_) that acts as a gateway.
Kroki server is built using {uri-maven}[Maven].

umlet::
A tiny Java API on top of _UMlet_ (mini) to generate diagrams.

nomnoml::
A Node.js CLI on top of the _Nomnoml_ diagram library.

vega::
A Node.js CLI on top of the _vega_ diagram library. Also supports Vega-Lite concise grammar.

mermaid::
A companion web server written in JavaScript (powered by _micro_) that provides _Mermaid_ diagram library.

bpmn::
A companion web server written in JavaScript (powered by _micro_) that provides _bpmn-js_ diagram library.

bytefield::
A Node.js CLI on top of the _bytefield-svg_ diagram library.

wavedrom::
A Node.js CLI on top of the _wavedrom_ diagram library.

excalidraw::
A companion web server written in JavaScript (powered by _micro_) that provides _Excalidraw_.

diagrams.net::
A companion web server written in JavaScript (powered by _micro_) that provides _diagrams.net_.

== Build

=== Gateway Server

The first step is to build the project using Maven:

 $ make buildServer

=== Docker Images

To build all the Docker images, use the following command:

 $ sudo make buildDockerImages

NOTE: `sudo` might not be needed depending on your distribution and `docker` configuration.

== Run

Once the Docker images are built, you can run Kroki using `docker`:

 $ docker run -d -p 8000:8000 yuzutech/kroki

=== Companion Containers

If you want to use one of the following diagram libraries then you will also need to start the corresponding companion container:

yuzutech/kroki-mermaid::
Mermaid

yuzutech/kroki-bpmn::
BPMN

yuzutech/kroki-excalidraw::
Excalidraw

yuzutech/kroki-diagramsnet (experimental)::
diagrams.net

You can use `docker-compose` to run multiple containers:

.docker-compose.yml
[source,yml]
----
version: "3"
services:
  core:
    image: yuzutech/kroki
    environment:
      - KROKI_MERMAID_HOST=mermaid
      - KROKI_BPMN_HOST=bpmn
      - KROKI_EXCALIDRAW_HOST=excalidraw
    ports:
      - "8000:8000"
  mermaid:
    image: yuzutech/kroki-mermaid
    expose:
      - "8002"
  bpmn:
    image: yuzutech/kroki-bpmn
    expose:
      - "8003"
  excalidraw:
    image: yuzutech/kroki-excalidraw
    expose:
      - "8004"
  # experimental!
  diagramsnet:
    image: yuzutech/kroki-diagramsnet
    expose:
      - "8005"
----

 $ docker-compose up -d