WasmEdge WASI-Logging example

This is an example of using the WASI-Logging plugin of WasmEdge in Rust.

Prerequisites

Install Rust

Follow the instructions below to install Rust and wasm32-wasip1 target.

bash

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-wasip1

Install WasmEdge and WASI-Logging plugin

Build wasmedge from scratch with the WASI-Logging plugin enabled.

git clone https://github.com/WasmEdge/WasmEdge.git --depth 1
cd WasmEdge
mkdir build; cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make -j
# WASI-Logging plug-in is a built-in plug-in in WasmEdge library.

(Optional) Download WASI-Logging WIT files

In the example, we already prepare the WIT files in wit directory. The WIT files are from wasi-logging repo. You can get the same WIT files by doing the following steps.

git clone https://github.com/WebAssembly/wasi-logging.git
cd wasi-logging
git checkout 3293e84de91a1ead98a1b4362f95ac8af5a16ddd
cp -r wit /path/to/wasmedge/examples/plugin/wasi-logging

Build the example

cargo build --target wasm32-wasip1

Then we get target/wasm32-wasip1/debug/wasi-logging-example.wasm.

Logging context

For the logging context of the log function in Rust, developers can use the "" or "stdout" to log to the console, use the "stderr" to log to standard error output, or use the file name to log into the target file.

Run the example

We can run this example with wasmedge like

wasmedge target/wasm32-wasip1/debug/wasi-logging-example.wasm

This example should run successfully and print out the log as follow.

[2024-05-21 13:43:53.240] [info] ===================================
[2024-05-21 13:43:53.240] [info] Stdout Message Demo
[2024-05-21 13:43:53.240] [info] -----------------------------------
[2024-05-21 13:43:53.240] [trace] Trace Level Message
[2024-05-21 13:43:53.240] [debug] Debug Level Message
[2024-05-21 13:43:53.240] [info] Info Level Message
[2024-05-21 13:43:53.240] [warning] Warn Level Message
[2024-05-21 13:43:53.240] [error] Error Level Message
[2024-05-21 13:43:53.240] [critical] Critical Level Message
[2024-05-21 13:43:53.240] [info] ===================================
[2024-05-21 13:43:53.240] [info] Stderr Message Demo
[2024-05-21 13:43:53.240] [info] -----------------------------------
[2024-05-21 13:43:53.240] [trace] Trace Level Message
[2024-05-21 13:43:53.240] [debug] Debug Level Message
[2024-05-21 13:43:53.240] [info] Info Level Message
[2024-05-21 13:43:53.240] [warning] Warn Level Message
[2024-05-21 13:43:53.240] [error] Error Level Message
[2024-05-21 13:43:53.240] [critical] Critical Level Message
[2024-05-21 13:43:53.240] [info] ===================================
[2024-05-21 13:43:53.240] [info] File Message Demo: log/output.log
[2024-05-21 13:43:53.240] [info] -----------------------------------
[2024-05-21 13:43:53.240] [info] ===================================
[2024-05-21 13:43:53.240] [info] File Message Demo: log/output2.log
[2024-05-21 13:43:53.240] [info] -----------------------------------
[2024-05-21 13:43:53.240] [info] ===================================
[2024-05-21 13:43:53.240] [info] File Message Demo: continue to log/output.log
[2024-05-21 13:43:53.240] [info] -----------------------------------

The log file log/output.log will be generated:

text

[2024-05-21 13:44:50.966] [trace] Trace Level Message
[2024-05-21 13:44:50.966] [debug] Debug Level Message
[2024-05-21 13:44:50.966] [info] Info Level Message
[2024-05-21 13:44:50.966] [warning] Warn Level Message
[2024-05-21 13:44:50.966] [error] Error Level Message
[2024-05-21 13:44:50.966] [critical] Critical Level Message
[2024-05-21 13:44:50.966] [trace] Trace Level Message
[2024-05-21 13:44:50.966] [debug] Debug Level Message
[2024-05-21 13:44:50.966] [info] Info Level Message
[2024-05-21 13:44:50.966] [warning] Warn Level Message
[2024-05-21 13:44:50.966] [error] Error Level Message
[2024-05-21 13:44:50.966] [critical] Critical Level Message

The log file log/output2.log will be generated:

text

[2024-05-21 13:44:50.966] [trace] Trace Level Message
[2024-05-21 13:44:50.966] [debug] Debug Level Message
[2024-05-21 13:44:50.966] [info] Info Level Message
[2024-05-21 13:44:50.966] [warning] Warn Level Message
[2024-05-21 13:44:50.966] [error] Error Level Message
[2024-05-21 13:44:50.966] [critical] Critical Level Message