system-viz is a tiny, simple library to visualize a system, constructed using Stuart Sierra's component library.
Use of this project requires that Graphviz is installed, which can be checked by running dot -V at the command line. If it's not installed, you can do the following:
| platform | directions |
|---|---|
| Linux | install graphviz using your package manager |
| OS X | download the installer |
| Windows | download the installer |
Here, we are creating a very hypothetical stand-in for some kind of system:
(require '[com.walmartlabs.system-viz :refer [visualize-system]]
'[com.stuartsierra.component :as component])
(def sys
(component/system-map
:auth (component/using {} {:delegate :local/auth})
:local/auth (component/using {} [:database])
:database (component/using {} [])
:handler (component/using {} [:database :message-queue])
:message-queue {}
:router (component/using {} {:queue :message-queue})
:web-server (component/using {} [:auth :router :handler])))
(visualize-system sys)This will open a window displaying an image somewhat like:
Dependencies between components are shown as arrows; the arrows are only labeled when the component's local key for the dependency is different from the target component's system key.
visualize-system returns the system it is passed; it is intended as a filter used for side effects (creating and opening the graph image).
Some systems will render more readibly with a horizontal layout.
(visualize-system sys {:horizontal true})will render as:
Sometimes, in larger and more complex projects, you may have errors in your inter-component dependencies. The component library detects this, but the exception can be extremely difficult to parse.
system-viz can help here: it will identify dependencies that link to non-existent components, highlighting the missing components in red:
The visual representation of the components in the graph can be adjusted for
specific nodes, using particular component keys in the :systemviz namespace.
Example:
(require '[com.walmartlabs.system-viz :refer [visualize-system]]
'[com.stuartsierra.component :as component])
(def sys
(component/system-map
:auth (component/using {} {:delegate :local/auth})
:local/auth (component/using {:systemviz/color :magenta} [:database])
:database (component/using {:systemviz/highlight true} [])
:handler (component/using {} [:database :message-queue])
:message-queue {:systemviz/attrs {:shape :box3d}}
:router (component/using {} {:queue :message-queue})
:web-server (component/using {} [:auth :router :handler])))
:systemviz/color
Sets the color of the node to the provided value, and sets the style of the node to filled.
:systemviz/highlight
Sets the color of the node to a light blue, and increases the font size from the default 14 point to 24 point.
:systemviz/attrs
Allows the specification of arbitrary Graphviz node attributes as a nested map of keys and values. Values should be strings, numbers, or keywords and will be quoted as necessary.
Two options to visualize-system support customization:
:highlight
Defines the set of GraphViz node attributes used when a component
has the :systemviz/highlight attribute.
:decorator
A function that is passed each component's key and component map and return nil, or a map of GraphViz node attributes.
For example, this could allow easy customization of components based on the namespace of thier component keys, or other factors.
Copyright © 2015-2018 Walmart Labs
Distributed under the Apache Software License 2.0.