# DFD
DFD (Data Flow Diagram) Generator - Commandline tool to generate
diagrams as images in various formats (SVG, PNG, JPG, PDF, etc.) from
source text files.
The source for this project is [available here][src].
The package page is [available here][pypi].
## Scope
The present tool allows to create diagrams following the "Structured
Analysis / Stuctured Design" (SA/SD) modelling technique as described
by Edward Yourdon.
SA/RT (which is SA/SD with a real-time extension), can be found in the
design of real-time and embedded systems.
Example: [Firmware modelling of the Active Descent
System](https://www.spyr.ch/ps/ads/qm/node18.html) of the [Rosetta
Lander](https://en.wikipedia.org/wiki/Rosetta_(spacecraft))
spacecraft.
Surprisingly, SA/RT is also well-suited to the analyse and design of
web micro-services and IoT architectures.
## Summary
Data Flow Diagram are used to model the flow and processing of
information through a system.
```data-flow-diagram example.svg
process P Process
process P2 Process
entity E Entity
store S Store
channel C Channel
E --> P flow
P ::> P2 signal
P <-> S bidirectional flow
P --- C undirected flow
```
## Syntax and examples
See the [documentation page][doc].
## Dependencies
* Python3
* Graphviz
## Installing via pip3
```
[sudo] pip3 install data-flow-diagram
```
## Installation troubleshooting
If you get an error at runtime like:
```
ModuleNotFoundError: No module named 'reportlab.graphics._renderPM'
```
you may have to reinstall reportlab:
```
[sudo] python3 -m pip install --upgrade --force-reinstall reportlab
```
## Usage
`data-flow-diagram -h` says:
```
usage: data-flow-diagram [-h] [--output-file OUTPUT_FILE] [--markdown]
[--format FORMAT] [--percent-zoom PERCENT_ZOOM]
[--background-color BACKGROUND_COLOR] [--debug]
[INPUT_FILE]
Command-line DFD diagram generator. Converts a textual description into a
graphic file.
positional arguments:
INPUT_FILE UML sequence input file; if omitted, stdin is used
options:
-h, --help show this help message and exit
--output-file OUTPUT_FILE, -o OUTPUT_FILE
output file name; pass '-' to use stdout; if
omitted, use INPUT_FILE base name with '.svg'
extension, or stdout
--markdown, -m consider snippets between opening marker:
```data-flow-diagram OUTFILE, and closing marker:
``` allowing to generate all diagrams contained in
an INPUT_FILE that is a markdown file
--format FORMAT, -f FORMAT
output format: gif, jpg, tiff, bmp, pnm, eps, pdf,
svg (any supported by Graphviz); default is svg
--no-graph-title suppress graph title
--no-check-dependencies
suppress dependencies checking
--debug emits debug messages
See https://github.com/pbauermeister/dfd for information, syntax and
examples.
```
[src]: https://github.com/pbauermeister/dfd
[pypi]: https://pypi.org/project/data-flow-diagram
[doc]: https://github.com/pbauermeister/dfd/tree/master/doc/README.md
