Rusty V8 Binding
V8 Version: 8.8.278.2
Provide high quality Rust bindings to V8's C++ API. The API should match the original API as closely as possible.
Do not introduce additional call overhead. (For example, previous attempts at Rust V8 bindings forced the use of Persistent handles.)
Do not rely on a binary
libv8.abuilt outside of cargo. V8 is a very large project (over 600,000 lines of C++) which often takes 30 minutes to compile. Furthermore, V8 relies on Chromium's bespoke build system (gn + ninja) which is not easy to use outside of Chromium. For this reason many attempts to bind to V8 rely on pre-built binaries that are built separately from the binding itself. While this is simple, it makes upgrading V8 difficult, it makes CI difficult, it makes producing builds with different configurations difficult, and it is a security concern since binary blobs can hide malicious code. For this reason we believe it is imperative to build V8 from source code during "cargo build".
Publish the crate on crates.io and allow docs.rs to generate documentation. Due to the complexity and size of V8's build, this is nontrivial. For example the crate size must be kept under 10 MiB in order to publish.
V8 is very large and takes a long time to compile. Many users will prefer to use a prebuilt version of V8. We publish static libs for every version of rusty v8 on Github.
Binaries builds are turned on by default:
cargo build will initiate a download from github to get the static lib. To disable this build using the
V8_FROM_SOURCE environmental variable.
When making changes to rusty_v8 itself, it should be tested by build from source. The CI always builds from source.
RUSTY_V8_MIRROR environment variable
Tells the build script where to get binary builds from. Understands
https:// URLs, and file paths. The default is https://github.com/denoland/rusty_v8/releases/download.
File-based mirrors are good for using cached downloads. First, point the environment variable to a suitable location:
# you might want to add this to your .bashrc $ export RUSTY_V8_MIRROR=$HOME/.cache/rusty_v8
Then populate the cache:
#!/bin/bash # see https://github.com/denoland/rusty_v8/releases for REL in v0.9.0 v0.10.0; do mkdir -p $RUSTY_V8_MIRROR/$REL for FILE in \ librusty_v8_debug_x86_64-unknown-linux-gnu.a \ librusty_v8_release_x86_64-unknown-linux-gnu.a \ ; do if [ ! -f $RUSTY_V8_MIRROR/$REL/$FILE ]; then wget -O $CACHE_DIR/$REL/$FILE \ https://github.com/denoland/rusty_v8/releases/download/$REL/$FILE fi done done
Build V8 from Source
V8_FROM_SOURCE=1 cargo build -vv to build the crate completely from source.
The build scripts on Python 2.7, not Python 3. Do not open issues with us regarding Python 3; it is a non-trivial problem that must be fixed in Chromium..
For linux builds: glib-2.0 development files need to be installed such that pkg-config can find them. On Ubuntu, run
sudo apt install libglib2.0-dev to install them.
For Windows builds: the 64-bit toolchain needs to be used. 32-bit targets are not supported.
The build depends on several binary tools:
ninja and a recent version of
clang (V8 relies on bleeding edge features). Because these are not generally available they are automatically downloaded during the build by default. It should be possible to opt out of the gn and ninja download by specifying the
$NINJA environmental variables. The clang download can be skipped by providing a
$CLANG_BASE_PATH environmental variable pointing to a recent
clang installation (currently LLVM v8.0+ or Apple clang v11.0+). You could also pass in additional arguments to
gn by setting the
$GN_ARGS environmental variable.
Env vars used in when building from source:
Building V8 takes over 30 minutes, this is too slow for me to use this crate. What should I do?
What are all these random directories for like
buildtools are these really necessary?
In order to build V8 from source code, we must provide a certain directory structure with some git submodules from Chromium. We welcome any simplifications to the code base, but this is a structure we have found after many failed attempts that carefully balances the requirements of cargo crates and GN/Ninja.
V8 has a very large API with hundreds of methods. Why don't you automate the generation of this binding code?
In the limit we would like to auto-generate bindings. We have actually started down this route several times, however due to many eccentric features of the V8 API, this has not proven successful. Therefore we are proceeding in a brute-force fashion for now, focusing on solving our stated goals first. We hope to auto-generate bindings in the future.
Why are you building this?
This is to support the Deno project. We previously have gotten away with a simpler high-level Rust binding to V8 called libdeno. But as Deno has matured we've found ourselves continually needing access to an increasing amount of V8's API in Rust.
When building I get unknown argument: '-gno-inline-line-tables'
export GN_ARGS="no_inline_line_tables=false" during build.