# DataFlow
Render graphs using a declarative markup. Currently supports DFD
(http://en.wikipedia.org/wiki/Data_flow_diagram) and sequence diagrams
(http://plantuml.sourceforge.net/sequence.html).
## Usage
The following forms are supported by DataFlow.
#### IDs
An ID can contain letters, numbers and underscores. It must start with a
letter.
```dot
my_id_contain_4_words
```
#### Strings
String literals are written using double quotes.
```dot
"this is a string and it can contain everything but double quotes and newlines"
```
**NOTE!** Escaping characters inside strings is not supported at the moment.
#### Text Blocks
Text blocks are special strings, enclosed in backticks, that are can span
multiple lines in the source document. The space characters before the first
non-space characters on each line are trimmed, regardless of the indentation.
```dot
`this is
a
textblock`
```
... is converted to:
```
this is
a
textblock
```
#### Arrays
Arrays can contain other values (arrays, strings, text blocks).
```dot
["hello", "world", ["I", "am", `nested
here`]]
```
#### Attributes
Attributes are key-value pairs for diagrams and nodes that are used by
output renderers. Attributes are enclosed by curly brackets. For nodes that
can contain other nodes, attributes must appear before nodes.
Keys have the same rules as IDs. Values can be strings or text blocks.
```dot
{
key1 = "attr value"
key2 = `attr
value`
key3 = ["value1", "value2"]
}
```
#### `diagram`
`diagram` is the top-level form and must appear exactly once in a DataFlow
document. It can contain attributes and nodes.
```dot
diagram {
title = "My diagram"
}
```
#### `boundary`
The `boundary` form declares a TrustBoundary node that can contain
attributes and other nodes. Boundaries are only allowed in the top-level
diagram and they must have unique IDs.
```dot
diagram {
boundary my_boundary {
title = "My System"
}
}
```
#### nodes: `io`, `function`, `database`
The `io`, `function` and `database` forms declare `InputOutput`, `Function` and
`Database` nodes, respectively. The nodes have IDs and they can contain
attributes. Empty attribute brackets can be omitted.
```dot
diagram {
io thing1
io thing2 {
title = "Thing 2"
}
}
```
#### `->`
The `->` form declares a `Flow` between the nodes referenced by their
IDs. It can contain attributes. Empty attribute brackets can be omitted.
Flows must be declared after all nodes.
Note that the arrow can be reversed as well (`<-`).
```dot
diagram {
thing1 -> thing2
thing1 <- thing2 {
operation = "Greet"
data = "A nice greeting"
}
}
```
#### Comment
Comments are written using `/*` and `*/` and are ignored by the Reader. They're
only used for human consumption.
```dot
diagram {
/* I can write
* whatever I
* want in here! */
}
```
## Example
The image from the top of this README is rendered from the following DataFlow
document.
```dot
diagram {
title = "Webapp"
/* Some comment about this... */
threats = `
No particular threats at this point.
It's **extremely** safe.`
boundary {
title = "Browser"
function client {
title = "Client"
}
}
boundary {
title = "Amazon AWS"
function server {
title = "Web Server"
}
database logs {
title = "Logs"
}
}
io analytics {
title = "Google Analytics"
}
client -> server {
operation = "Request /"
description = `User navigates with a browser to see some content.`
}
server -> logs {
operation = "Log"
data = `The user
IP address.`
description = `Logged to a ELK stack.`
}
server -> client {
operation = "Response"
data = "User Profile"
description = `The server responds with some HTML.`
}
analytics <- client {
operation = "Log"
data = "Page Navigation"
description = `The Google Analytics plugin sends navigation
data to Google.`
}
}
```
## Run DataFlow
The `dataflow` executable takes an output format and a DataFlow source document
and writes the output to `stdout`.
```bash
dataflow (dfd|seq) FILE
```
## DFD
To use the *DFD* output you need [Graphviz](http://www.graphviz.org/) installed.
```bash
dataflow dfd webapp.flow | dot -Tpng > webapp.png
```
### Output
## Sequence Diagram
You can use [PlantUML](http://plantuml.sourceforge.net/) to generate a sequence
diagram.
```bash
dataflow seq webapp.flow | java -Djava.awt.headless=true -jar plantuml.jar -tpng -pipe > webapp.png
```
### Output
## Templating
You can use [Hastache](https://github.com/lymar/hastache) to output arbitrary
text with its Mustache-like templates.
```bash
dataflow template template.ha webapp.flow > webapp.html
```
### Built-in Functions and Values
* `markdown` - Convert the attribute at the given key from Markdown to HTML.
```mustache
{{#markdown}}my_markdown_attr{{/markdown}}
```
* `html_linebreaks` - Replace `\n` with `
` elements in the attribute at
the given key, to retain linebreaks in HTML output.
```mustache
{{#html_linebreaks}}my_formatted_attr{{/html_linebreaks}}
```
* `filename_without_extension` - The input `.flow` file name with no path and
no extension. Useful when generating graphics and text/HTML with matching
filenames (e.g. `my-flow.html` includes `my-flow.png`).
```mustache
```
* `flows` - a list of all the Flow nodes in the diagram. Attributes of the
flow is accessible inside the iteration scope, including a `number`.
```mustache
{{#flows}}
- {{number}} - {{description}}
{{/flows}}
```
For an example see [template.ha](examples/template.ha) and the output HTML in
[webapp.html](examples/webapp.html).
### Output
## Makefile Example
The following Makefile finds `.flow` sources in `src` and generates DFDs, in
SVG format, in `dist`.
```make
SOURCES=$(shell find src/*.flow)
TARGETS=$(SOURCES:src/%.flow=dist/%.dfd.svg)
K := $(if $(shell which dataflow),,$(error "No dataflow executable in PATH. See https://github.com/SonyMobile/dataflow for install instructions)))"))
dist/%.dfd.svg: src/%.flow
@dataflow dfd $< | dot -Tsvg > $@
dfd: $(TARGETS)
clean:
rm -f $(TARGETS)
```
## Build Instructions
See [BUILD.md](BUILD.md).
## License
BSD-3, see [LICENSE](LICENSE).