willthames / ansible-inventory-grapher

Summary

ansible-inventory-grapher creates a dot file suitable for use by graphviz

Requires:

• ansible
• graphviz

Getting started

pip install ansible-inventory-grapher

Usage

Usage: ansible-inventory-grapher [options] pattern1 [pattern2...]

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -i INVENTORY          specify inventory host file [/etc/ansible/hosts]
  -d DIRECTORY          Location to output resulting files [current directory]
  -o FORMAT, --format=FORMAT
                        python format string to name output files (e.g.
                        {}.dot) [defaults to stdout]
  -q, --no-variables    Turn off variable display in default template
  -t TEMPLATE           path to jinja2 template used for creating output
  -T                    print default template
  -a ATTRIBUTES         include top-level graphviz attributes from
                        http://www.graphviz.org/doc/info/attrs.html
                        [rankdir=TB;]
  --ask-vault-pass      prompt for vault password
  --vault-password-file=VAULT_PASSWORD_FILE
                        Location of file with cleartext vault password

Using the example inventory in https://github.com/willthames/ansible-ec2-example, we can generate the dot files for two of the example web servers using:

bin/ansible-inventory-grapher -i ../ansible-ec2-example/inventory/hosts \
  prod-web-server-78a prod-web-server-28a \
  -d test --format "test-{hostname}.dot"

You can add the -a option to insert a string with graphviz attributes (http://www.graphviz.org/doc/info/attrs.html) to apply to the root level of the graph. Some fun examples:

# transpose the tree so it grows from left-right instead of top-bottom
-a "rankdir=LR;"

# circular layout, with group nodes shaded grey
-a "layout=circo; overlap=false; splines=polyline;\
  node [ style=filled fillcolor=lightgrey ]"

# orthogonal, UML-like inheritance connectors
-a "rankdir=LR; splines=ortho; ranksep=2;\
  node [ width=5 style=filled fillcolor=lightgrey ];\
  edge [ dir=back arrowtail=empty ];"

You can replace the default template (which can be seen by passing the -T variable to ansible-inventory-grapher) with a template file that can be passed with the -t option.

The resulting graphs can then be converted to pngs using:

for f in test/*.dot ; do dot -Tpng -o test/`basename $f .dot`.png $f; done

Or the whole thing can now be done in one pipeline (only works for one pattern) straight to image viewer (imagemagick's display in this example)

bin/ansible-inventory-grapher -i ../ansible-ec2-example/inventory/hosts \
  prod-web-server-1a | dot -Tpng | display png:-

This works with valid Ansible patterns now although only hosts and groups have been tested.