Get Random - WASI Example

Full documentation on the OutLayer dashboard.

Simple WASM binary for testing NEAR OutLayer platform with WASI support.

Description

Generates a random number in the specified range using rand crate with WASI random source. Reads input from stdin and writes output to stdout.

Input Format

{
  "min": 0,
  "max": 100
}

Output Format

{
  "random_number": 42
}

Building

# Add WASI target
rustup target add wasm32-wasip1

# Build
cargo build --release --target wasm32-wasip1

# Output: target/wasm32-wasip1/release/random-ark.wasm (~111KB)

Local Testing

# Test with wasmtime
echo '{"min":1,"max":100}' | wasmtime target/wasm32-wasip1/release/random-ark.wasm

# Expected output: {"random_number":42}  (some number between 1-100)

Usage with NEAR OutLayer

1. Push this code to a GitHub repository (e.g., https://github.com/zavodil/random-ark)

2. Call request_execution on the OffchainVM contract:

near call outlayer.testnet request_execution '{
  "code_source": {
    "repo": "https://github.com/zavodil/random-ark",
    "commit": "main",
    "build_target": "wasm32-wasip1"
  },
  "resource_limits": {
    "max_instructions": 10000000,
    "max_memory_mb": 128,
    "max_execution_seconds": 60
  },
  "input_data": "{\"min\":1,\"max\":100}"
}' --accountId your-account.testnet --deposit 0.1

3. Worker will:
   • Compile the WASM in sandboxed Docker container
   • Execute with wasmi (WASI P1) or wasmtime (WASI P2)
   • Return the random number as readable text (not bytes!)
   • Show result in NEAR explorer

Unit Tests

cargo test