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https://github.com/fluencelabs/wasmer
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33 lines
1.1 KiB
Markdown
33 lines
1.1 KiB
Markdown
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# WASI plugin example
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In this example we extend the imports of Wasmer's WASI ABI to demonstrate how custom plugins work.
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See the `wasmer/examples/plugin.rs` file for the source code of the host system.
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## Compiling
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```
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# Install an up to date version of Rust nightly
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# Add the target
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rustup target add wasm32-unknown-wasi
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# build it
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cargo build --release --target=wasm32-unknown-wasi
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# copy it to examples folder
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cp ../../target/wasm32-unknown-wasi/release/plugin-for-example.wasm ../
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```
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## Running
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```
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# Go back to top level Wasmer dir
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cd ..
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# Run the example
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cargo run --example plugin
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```
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## Explanation
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In this example, we instantiate a system with an extended (WASI)[wasi] ABI, allowing our program to rely on Wasmer's implementation of the syscalls defined by WASI as well as our own that we made. This allows us to use the full power of an existing ABI, like WASI, and give it super-powers for our specific use case.
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Because the Rust WASI doesn't support the crate type of `cdylib`, we have to include a main function which we don't use.
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[wasi]: https://hacks.mozilla.org/2019/03/standardizing-wasi-a-webassembly-system-interface/
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