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What is OpenWeave?

Weave is the network application layer that provides a secure, reliable communications backbone for Nest's products. OpenWeave is the open source release of Weave.

At Google, we believe the core technologies that underpin connected home products need to be open and accessible. Alignment around common fundamentals will help products securely and seamlessly communicate with one another. Google's first open source release was our implementation of Thread, OpenThread. OpenWeave can run on OpenThread, other IPv6-bearing network links, or Bluetooth Low Energy, and is another step in the direction of making our core technologies more widely available.

What is OpenWeave WDLC?

This package makes available the Weave Data Language (WDL) compiler (WDLC). WDL is Weave's publish and subscribe schema language. The WDLC compiler can be used to compile (i.e., validate and code generate) schema written against the WDL specification.

Some notable features of WDLC include:

• Generate code against user-provided, language- and run time-specific templates that conform to WDL template syntax.
• Compare a body of schema against a previous revision of schema to run additional validations.

Getting started with OpenWeave WDLC

Building WDLC

If you are not using a prebuilt distribution of WDLC, building WDLC should be a straightforward, two-step process:

% ./configure
% make

Although not strictly necessary, the additional step of sanity checking the build results is recommended:

% make check

The configure step can also set the installation prefix, overriding the default "/usr/local". Creating an arbitrarily relocatable WDLC installation might, for example, specify --prefix=/. See "Installing WDLC" below for more information.

Dependencies

The configure step recognizes and accepts both the PROTOC and PYTHON enviroment variables, which may also be specified after configure on the command line. These may be used to override the instance of the Google Protocol Buffers (protobuf) Compiler, protoc, and the Python interpreter, python, respectively, otherwise found via the PATH environment variable.

WDLC depends on and requires a version of protoc between 3.5.1 and 3.7.1, inclusive and python 2.7. Python later than 2.7, including Python 3, is not supported by WDLC at this time.

In addition, the following Python packages are required:

• virtualenv
• pip

If you want to modify or otherwise maintain the OpenWeave WDLC build system, see "Maintaining WDLC" below for more information.

Linux

On Debian-based Linux distributions such as Ubuntu, these collective dependencies can be satisfied with the following:

% sudo apt-get install protobuf-compiler python2.7 python-pip python-virtualenv

Mac OS X

On Mac OS X, these collective dependencies can be installed and satisfied using Brew:

% brew install protobuf

Mac OS X, including Mojave, supports Python 2.7 by default. However, the Python pip and virtualenv dependencies can be installed and satisfied as follows:

• pip
• virtualenv

Installing WDLC

To install WDLC for your use simply invoke:

% make install

to install WDLC in the location indicated by the --prefix configure option (default "/usr/local"). If you intended an arbitrarily relocatable WDLC installation and passed --prefix=/ to configure, then you might use DESTDIR to, for example install WDLC in your user directory:

% make DESTIDIR="${HOME}" install

Note that WDLC allows the installation of multiple minor versions of itself in parallel with "versioned" directories under bin, include, lib, and share. For example, for WDLC version 1.0.7:

• ${DESTDIR}${prefix}bin/wdlc-1.0
• ${DESTDIR}${prefix}include/wdlc-1.0
• ${DESTDIR}${prefix}lib/wdlc-1.0
• ${DESTDIR}${prefix}share/wdlc-1.0

where the actual WDLC executable would be found under ${DESTDIR}${prefix}bin/wdlc-1.0/wdlc.

If it would not overwrite an existing installation, WDLC will also install a non-versioned convenience binary symbolic link to ${DESTDIR}${prefix}bin/wdlc.

Using WDLC

Please run wdlc --help to see a full list of options.

Validate device identity trait:

% wdlc --check --output ./build -I ~/schema/openweave-schema-vendor-common ~/schema/openweave-schema-vendor-common/weave/trait/description/device_identity_trait.proto

Code-generate for Weave Device C++:

% wdlc --gen weave-device-cpp --output ./build -I ~/schema/openweave-schema-vendor-common ~/schema/openweave-schema-vendor-common/weave/trait/description/device_identity_trait.proto

Code-generate using base protoc C++ template:

% wdlc --gen cpp --output ./build -I ~/schema/openweave-schema-vendor-common ~/schema/openweave-schema-vendor-common/weave/trait/description/device_identity_trait.proto

Validate all traits in a given folder:

% wdlc --check --output ./build -I ~/schema/openweave-schema-vendor-common ~/schema/openweave-schema-vendor-common/weave/trait/located

Code-generate schema + dependencies:

% wdlc -I ~/openweave-schema-vendor-nest -I ~/openweave-schema-vendor-common --gen weave-device-cpp --gen_dependencies --output ./build ~/openweave-schema-vendor-nest/nest/resource/nest_detect_resource.proto ~/openweave-schema-vendor-nest/nest/resource/nest_guard_resource.proto

Maintaining WDLC

If you want to maintain, enhance, extend, or otherwise modify WDLC, it is likely you will need to change its build system, based on GNU autotools, in some circumstances.

After any change to the WDLC build system, including any Makefile.am files or the configure.ac file, you must run the bootstrap or bootstrap-configure (which runs both bootstrap and configure in one shot) script to update the build system.

Dependencies

Due to its leverage of GNU autotools, if you want to modify or otherwise maintain the OpenWeave WDLC build system, the following additional packages are required and are invoked by bootstrap:

• autoconf
• automake
• libtool

Linux

On Debian-based Linux distributions such as Ubuntu, these dependencies can be satisfied with the following:

% sudo apt-get install autoconf automake libtool

Mac OS X

On Mac OS X, these dependencies can be installed and satisfied using Brew:

% brew install autoconf automake libtool

Implementation Details

Today, WDLC leverages the Google Protocol Buffers (protobuf) Compiler (protoc) as its backend with a custom Python plugin used to interpret the protoc intermediate output and then to subsequently validate and code generate against input schema.

Code generation, today, is handled via the Python Jinja2 module, using a template format specific to WDL.

Need help?

There are numerous avenues for OpenWeave support:

• Bugs and feature requests — submit to the Issue Tracker
• Stack Overflow — post questions using the openweave tag
• Google Groups — discussion and announcements at openweave-users

The openweave-users Google Group is the recommended place for users to discuss OpenWeave and interact directly with the OpenWeave team.

Directory Structure

The OpenWeave WDLC repository is structured as follows:

File / Folder	Contents
aclocal.m4	GNU autotools auto-generated file containing autoconf macros used by the OpenWeave WDLC build system.
backend	The compiler backend that effects the actual parsing, validation, and code generation.
bootstrap	GNU autotools bootstrap script for the OpenWeave WDLC build system.
bootstrap-configure	Convenience script that will bootstrap the OpenWeave WDLC build system, via bootstrap, and invoke configure.
build/	OpenWeave WDLC-specific build system support content.
CHANGELOG	Description of changes to OpenWeave from release-to-release.
configure	GNU autotools configuration script for OpenWeave.
configure.ac	GNU autotools configuration script source file for OpenWeave WDLC.
CONTRIBUTING.md	Guidelines for contributing to OpenWeave WDLC.
.default-version	Default OpenWeave WDLC version if none is available via source code control tags, .dist-version, or .local-version.
include	GNU autotools configuration header (unused).
LICENSE	OpenWeave WDLC license file (Apache 2.0).
Makefile.am	Top-level GNU automake makefile source.
Makefile.in	Top-level GNU autoconf makefile source.
README.md	This file.
test/	Test schema used to exercise and validate WDL syntax code generation.
third_party/	Third-party code used by OpenWeave WDLC.
wdl/	Core WDL schema data types and defintions.
wdlc.sh.in	WDL front end implementation template.
weave/	Additional, common WDL schema data types and definitions.

Contributing

We would love for you to contribute to OpenWeave WDLC and help make it even better than it is today! See the CONTRIBUTING.md file for more information.

Versioning

OpenWeave WDLC follows the Semantic Versioning guidelines for release cycle transparency and to maintain backwards compatibility.

License

License and the Weave and OpenWeave Brands

The OpenWeave software is released under the Apache 2.0 license, which does not extend a license for the use of the Weave and OpenWeave name and marks beyond what is required for reasonable and customary use in describing the origin of the software and reproducing the content of the NOTICE file.

The Weave and OpenWeave name and word (and other trademarks, including logos and logotypes) are property of Google LLC. Please refrain from making commercial use of the Weave and OpenWeave names and word marks and only use the names and word marks to accurately reference this software distribution. Do not use the names and word marks in any way that suggests you are endorsed by or otherwise affiliated with Nest without first requesting and receiving a written license from us to do so. See our Trademarks and General Principles page for additional details. Use of the Weave and OpenWeave logos and logotypes is strictly prohibited without a written license from us to do so.