nixgraph.md

nixgraph

nixgraph is a python library and command line utility for querying and visualizing dependency graphs for nix packages.

Table of Contents

• Getting Started
• Usage examples
  • Example: package runtime dependencies
  • Example: depth
  • Example: colorize
  • Example: inverse
  • Example: package buildtime dependencies
  • Example: output format
  • Example: pathnames

Getting Started

To get started, follow the Getting Started section from the main README.

Usage examples

In the below examples, we use nix package wget as an example target. To print wget out-path on your local system, try something like:

$ nix eval -f '<nixpkgs>' 'wget.outPath'
"/nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3"

Example: package runtime dependencies

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3

INFO     Loading runtime dependencies referenced by '/nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3'
INFO     Wrote: graph.png

By default nixgraph scans the given target and generates a graph that shows the direct runtime dependencies. The default output is a png image graph.png:

Example: depth

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3 --depth=2

By default, when --depth argument is not specified, nixgraph shows the direct dependencies. Increasing the --depth makes nixgraph walk the dependency chain deeper. For instance, with --depth=2, the output graph for wget becomes:

The value of --depth indicates the maximum depth between any two nodes in the resulting graph. For instance, in the above example, libunistring-1.0 gets included with --depth=2 because the shortest path between wget and libunistring is two hops deep (wget --> libidn2 --> libunistring).

Example: colorize

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3 --depth=2 --colorize='openssl|libidn'

--colorize allows highlighting nodes that match the specified regular expression:

Example: inverse

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3 --depth=2 --inverse='glibc'

--inverse makes it possible to draw the graph backwards starting from nodes that match the specified regular expression. For instance, the above command would show all the dependency paths from wget that lead to glibc:

--inverse is especially useful when working with larger graphs.

As an example, consider the following graph for git: (nixgraph /nix/store/sb0fay7ihrqibk325qyx0377ywrfdnxp-git-2.38.1 --depth=3 --colorize="openssl-3|sqlite-3")

To find out what are all the runtime dependency paths from git to the highlighted nodes openssl or sqlite in the above graph, run the following command:

# --depth=100: make sure the output graph includes "long enough" dependency chains
# --inverse="openssl-3|sqlite-3": draw the graph backwards starting from nodes that
#                                 match the specified reqular expression
# --colorize="openssl-3|sqlite-3": colorize the matching nodes
nixgraph  /nix/store/sb0fay7ihrqibk325qyx0377ywrfdnxp-git-2.38.1 --depth=100 --colorize="openssl-3|sqlite-3" --inverse="openssl-3|sqlite-3"

The output now becomes:

The output graph shows that there are three dependency paths from git to openssl-3.0.7 and one dependency path that leads to sqlite-3.39.4.

Example: package buildtime dependencies

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3 --buildtime

Specifying --buildtime makes nixgraph visualize the buildtime dependencies instead of runtime dependencies:

Example: output format

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3 --out="graph.dot"

By default nixgraph outputs the graph in png image graph.png. To change the output file name and format, use the --out argument. The output filename extension determines the output format. As an example, the above command would output the graph in dot format. For a full list of supported output formats, see: https://graphviz.org/doc/info/output.html. In addition to graphviz supported output formats, the tool supports output in csv to allow post-processing the output data.

Example: pathnames

$ nixgraph /nix/store/8nbv1drmvh588pwiwsxa47iprzlgwx6j-wget-1.21.3 --depth=1 --pathnames

--pathnames argument allows adding store path to node label in the output graph: