example code fails...seems hopeless... is wasmer-js broken?

[onexdata]

I tried the example code on the website. I tried Node 18.x, 20.x, 22.x, they all say "TypeError": fetch failed" and "Error: not implemented... yet..."

For reference, here is the code I'm talking about, it fails at very next line from importinging, await.init()...

import { init, Wasmer } from "@wasmer/sdk";

await init();

const pkg = await Wasmer.fromRegistry("python/python");
const instance = await pkg.entrypoint.run({
    args: ["-c", "print('Hello, World!')"],
});

const { code, stdout } = await instance.wait();
console.log(`Python exited with ${code}: ${stdout}`);

Here is the error...

node:internal/deps/undici/undici:13185
      Error.captureStackTrace(err);
            ^
                                                                                                      TypeError: fetch failed                                                                                   at node:internal/deps/undici/undici:13185:13                                                          at async v_ (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:47648)
    at async R_ (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:48139)
    at async file:///C:/code/onexdata/wasm/wasmer/node-server/example.js:3:1 {
  [cause]: Error: not implemented... yet...
      at makeNetworkError (node:internal/deps/undici/undici:8968:35)
      at schemeFetch (node:internal/deps/undici/undici:10363:34)
      at node:internal/deps/undici/undici:10212:26
      at mainFetch (node:internal/deps/undici/undici:10231:11)
      at fetching (node:internal/deps/undici/undici:10179:7)
      at fetch (node:internal/deps/undici/undici:10048:20)
      at fetch (node:internal/deps/undici/undici:13183:10)
      at fetch (node:internal/bootstrap/web/exposed-window-or-worker:72:12)
      at v_ (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:46947)
      at R_ (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:48145)
}

Node.js v20.18.0

When I rewrite everything and use a polyfill for fetch, I produce this...

import { init, Wasmer } from "@wasmer/sdk";
import fetch from 'node-fetch';
import { createRequire } from 'module';
import { fileURLToPath } from 'url';
import fs from 'fs/promises';

const require = createRequire(import.meta.url);

// Custom fetch implementation that handles both HTTP and file protocols
global.fetch = async (urlOrRequest, options) => {
    const url = urlOrRequest instanceof URL ? urlOrRequest.href : urlOrRequest.toString();
    
    if (url.startsWith('file:')) {
        const filePath = fileURLToPath(url);
        const buffer = await fs.readFile(filePath);
        return new Response(buffer);
    }
    return fetch(url, options);
};

try {
    await init();
    
    const pkg = await Wasmer.fromRegistry("python/python");
    const instance = await pkg.entrypoint.run({
        args: ["-c", "print('Hello, World!')"],
    });

    const { code, stdout } = await instance.wait();
    console.log(`Python exited with ${code}: ${stdout}`);
} catch (error) {
    console.error('Error:', error);
}

Which generates this error, indicating python/python doesn't actually exist, is this accurate?

`WebAssembly.instantiateStreaming` failed because your server does not serve wasm with `application/wasm` MIME type. Falling back to `WebAssembly.instantiate` which is slower. Original error:
 TypeError [ERR_WEBASSEMBLY_RESPONSE]: WebAssembly response has unsupported MIME type 'null'
    at new NodeError (node:internal/errors:405:5)
    at node:internal/wasm_web_api:30:13 {
  code: 'ERR_WEBASSEMBLY_RESPONSE'
}
Error: Error: Unable to find "python/python" in the registry
    at e.wbg.__wbg_new_28c511d9baebfa89 (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:35384)
    at wasm://wasm/015c03b2:wasm-function[1466]:0x2fbfb8
    at wasm://wasm/015c03b2:wasm-function[6951]:0x4230c1
    at wasm://wasm/015c03b2:wasm-function[337]:0x10a2da
    at wasm://wasm/015c03b2:wasm-function[2038]:0x34ba1e
    at wasm://wasm/015c03b2:wasm-function[10511]:0x449902
    at wasm://wasm/015c03b2:wasm-function[9401]:0x44074e
    at v (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:2534)
    at o (file:///C:/code/onexdata/wasm/wasmer/node-server/node_modules/@wasmer/sdk/dist/index.mjs:11:2374) {
  detailedMessage: 'Unable to find "python/python" in the registry\n' +
    '\n' +
    'Caused by:\n' +
    "    0: failed to query package 'python/python': Could not fetch 'https://registry.wasmer.io/graphql'\n" +
    "    1: Could not fetch 'https://registry.wasmer.io/graphql'\n" +
    '    2: Invalid URL',
  causes: [
    "failed to query package 'python/python': Could not fetch 'https://registry.wasmer.io/graphql'",  
    "Could not fetch 'https://registry.wasmer.io/graphql'",
    'Invalid URL'
  ]
}

[onexdata]

also, wasmer run python/python -- -c "print('Hello World')" works... so it seems to be a problem in the codebase?

[onexdata]

I can also call wasmer cli from node, i.e. this works...

import { exec } from 'child_process';
import { promisify } from 'util';

const execAsync = promisify(exec);

async function runPython(code) {
    try {
        console.log('Running Python with Wasmer CLI...');
        // Escape the quotes properly
        const escapedCode = code.replace(/"/g, '\\"');
        const { stdout, stderr } = await execAsync(`wasmer run python/python -- -c "${escapedCode}"`);
        
        if (stderr) {
            console.error('Stderr:', stderr);
        }
        
        console.log('Stdout:', stdout);
        return { code: 0, stdout, stderr };
    } catch (error) {
        console.error('Error running Python:', error);
        return { 
            code: error.code || 1, 
            stdout: error.stdout, 
            stderr: error.stderr 
        };
    }
}

try {
    const result = await runPython('print("Hello, World!")');
    console.log(`Process exited with code ${result.code}`);
} catch (error) {
    console.error('Execution error:', error);
}

[onexdata]

ok, it really seems this SDK just doesn't work, or I am really missing something basic...?

I found these issues so far, being unable to run anything from @wasmer/sdk , yet wasmer cli works fine.

Fetch not used properly:
The SDK can't handle file:// URLs natively in Node.js (fetch issues)
Required a custom fetch handler to load the initial WASM file

Runtime Management Issues:
The error "Expected a runtime" suggests unclear runtime initialization requirements
Runtime.global(true) and new Runtime() both had issues

GraphQL/Registry Communication:
Issues with the GraphQL endpoint communications
The SDK struggled with request/response handling for registry queries, yet if I write them myself, I can also get past this.

Required special handling of headers and content types for me to get past this.

WebC Format Handling:
Problems with WebC format downloads and parsing... the SDK has Content-type mismatches between what the SDK expects and what the CDN serves. I had to rewrite this myself to get past it.

Error Handling:
Cryptic error messages ("oneshot canceled")... Can't seem to get past this, even with AI assistance.

[sigmaSd]

I run this with bun and it worked, I tried version 0.9.0 (latest currently)

import { init, Wasmer } from "@wasmer/sdk@0.9.0";

await init();

const pkg = await Wasmer.fromRegistry("python/python");
const instance = await pkg.entrypoint.run({
    args: ["-c", "print('Hello, World!')"],
});

const { code, stdout } = await instance.wait();
console.log(`Python exited with ${code}: ${stdout}`);

[geersch]

Experiencing the same issues with the node example in this repository using node 20.

TypeError: fetch failed
    at node:internal/deps/undici/undici:13392:13
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    ...
starter/node_modules/@wasmer/sdk/dist/index.mjs:11:47648)
  ...
  [cause]: Error: not implemented... yet...

Any updates on this?

[Flonk]

Still running into the same problem as of April 2025. It seems this package is unmaintained.

[sgulseth]

Using @wasmer/sdk in node fails with the fetch failed because it doesn't support fetching file:// however it seems to work fine if you instead import from @wasmer/sdk/node. Should be mentioned in the README