yangfmt

YANG code formatter

Install

Download the correct pre-compiled binary for your system from Releases.

Alternatively, if you have the Rust toolchain installed:

$ cargo install yangfmt

Usage

Pipe YANG source code to STDIN:

$ cat my-model.yang | yangfmt

Or specify a YANG file as the first positional argument:

$ yangfmt my-model.yang

Add -i to format the given YANG file in place:

$ yangfmt -i my-model.yang

Status

Pretty well tested, should be safe to use!

But please keep your code in version control just in case.

TODO:

• Automatically sort statements to comply with the canonical order (maybe behind a feature flag?)

• Fix all corner case crashes

  The YangModels repository contains over 80 000 YANG models (totalling over 2.2 GB). When running the formatter on every YANG file in this repository, there are still some corner cases that causes the formatter to crash.

• Handle comments in between string concatenations. Currently this causes a parse error. For example:

  pattern "abcdef"  // Comments here
        + "ghijkl"; // currently causes a parse error

  Fortunately I've never seen anybody do this, but it's legal YANG so it should be supported.

Ideas

• Automatically reflow the contents of description and tailf:info statements to comply with the configured line length. This would be a big developer experience win, but would make it impossible to add pre-formatted contents to these statements (such as ASCII diagrams, lists etc). If this is added, it will definitely be off by default.