Observed Error

When working with nested paths such as:

[package]
name = "dynamite-bud/py-worker-test-1"
version = "0.1.3"
description = "dynamite-bud/py-worker-test-1 py worker"

[dependencies]
"wasmer/python" = "^3.12.6"

[fs]
"/app/src" = "./src"

[[command]]
name = "script"
module = "wasmer/python:python"
runner = "wasi"

[command.annotations.wasi]
main-args = ["/app/src/main.py"]

Error

Running it with wasmer run . results in an error:
script: can't open file '/app/src/main.py': [Errno 44] No such file or directory

Expected Behaviour

Ideal toml file that works

[package]
name = "dynamite-bud/py-worker-test-1"
version = "0.1.3"
description = "dynamite-bud/py-worker-test-1 py worker"

[dependencies]
"wasmer/python" = "^3.12.6"

[fs]
"/src" = "./src"

[[command]]
name = "script"
module = "wasmer/python:python"
runner = "wasi"

[command.annotations.wasi]
main-args = ["/src/main.py"]

The above 👆🏼 works

On wapm.io, the adamz/quickjs package uses adamz/quickjs as its module name.

[package]
name = "adamz/quickjs"
version = "0.20210327.0"
description = "QuickJS is a small and embeddable JavaScript engine. It supports the ES2019 specification including modules, asynchronous generators and proxies."
repository = "https://github.com/saghul/wasi-lab"
homepage = "https://bellard.org/quickjs/"

[[module]]
name = "adamz/quickjs"   # <----------
source = "build/qjs.wasm"
abi = "wasi"

[module.interfaces]
wasi = "0.0.0-unstable"

[[command]]
name = "qjs"
module = "adamz/quickjs"

[[command]]
name = "quickjs"
module = "adamz/quickjs"

When wapm2pirita turns the tarball into a *.webc file, we rename the atom to just quickjs... However, the manifest still thinks it is called adamz/quickjs.

$ wapm2pirita dump volumes bin.webc
{
  "atoms": [
    {
      "name": "quickjs",
      "offset": 1983,
      "size": 2562768
    }
  ],
  "filesystem": {
    "atom": [],
    "metadata": []
  }
}

$ wapm2pirita dump manifest bin.webc
{
  "package": {
    "wapm": {
      "name": "adamz/quickjs",
      "version": "0.20210327.0",
      "homepage": "https://bellard.org/quickjs/",
      "repository": "https://github.com/saghul/wasi-lab",
      "description": "QuickJS is a small and embeddable JavaScript engine. It supports the ES2019 specification including modules, asynchronous generators and proxies."
    }
  },
  "atoms": {
    "adamz/quickjs": {
      "kind": "https://webc.org/kind/wasm",
      "signature": "sha256:b2KmvFyPjj4SpU4uy8VnTM/hx1+R2OTdbrs/7EIqTWw="
    }
  },
  "commands": {
    "qjs": {
      "runner": "https://webc.org/runner/wasi/command@unstable_",
      "annotations": {
        "wasi": {
          "atom": "adamz/quickjs",                <-----------------
          "package": null,
          "main_args": null
        }
      }
    ...
    }
  }
}

That means anything looking up the particular atom will fail because we're looking for adamz/quickjs when we should look for quickjs. That causes things like wasmer-pack to fail downstream.

$ wasmer-pack show ~/Downloads/quickjs-0.20210327.0.tar.gz
Error: Unable to load the package

Caused by:
    Could not find file "adamz/quickjs": could not find file or directory "adamz" (os error 2)

To fix this, we should change wasmer_pack::Module's name field from a String to some sort of ModuleName type which makes sure the manifest name is valid (e.g. it is an "identifier" that doesn't contain a /).

Here are the tarball and *.webc files we were testing against:

quickjs-0.20210327.0.tar.gz
quickjs-0.20210327.0.webc.zip

Packages will be bundled up and used on different machines, so any absolute paths in the wasmer.toml will almost certainly be broken. To prevent things like wasmerio/cargo-wasmer#18, the validate() function should reject absolute paths or anything pointing outside the base directory.

It would be ideal to support wcgi custom annotations (for example, to annotate if the program is on rfc mode or not).

That configuration should live in the toml runner annotations, but currently is not possible to define those in the toml.

Imagine you have a package containing some Python scripts. Rather than embedding a copy of the Python interpreter, you would prefer to use a Python package as a dependency and just add your *.py files to the package.

Your wasmer.toml might look like this:

[package]
name = "my/python-program"
version = "1.2.3"

[dependencies]
"wasmer/python" = "3.12"

[fs]
"/app/src" = "./src"
"/app/.env" = "./.env/" # Bundle the virtualenv

[[command]]
name = "script"
module = "wasmer/python:python" # The "python" atom from "wasmer/python"
runner = "wasi"

[annotations.wasi]
args = ["/app/main.py", "with", "--extra=flags"]
env = ["PYTHON_PATH=/app/.env:/etc/python3.12/site-packages"] # Make our virtualenv accessible

To make this use case work, we need a way to express module = "wasmer/python:python".

The wasmer.toml format doesn't give package developers a way to specify the entrypoint command, so code turning it into a webc manifest has to guess:

/// Infer the package's entrypoint.
///
/// there is no way to explicitly specify an entrypoint in a
/// `wasmer.toml` file. If there is exactly one command, we'll use that,
/// otherwise the entrypoint will be left unspecified.
fn entrypoint(manifest: &WasmerManifest) -> Option<String> {
    match manifest.command.as_deref() {
        Some([only_command]) => Some(only_command.get_name()),
        _ => None,
    }
}

We should allow package developers to specify the entrypoint so downstream users don't need to do wasmer run my/package --command=some-command every time.

Possible Syntax

Given a package with multiple commands, there are a couple different ways the entrypoint could be specified.

Option 1 - put it in [package]

[package]
name = "sharrattj/bash"
version = "1.2.3"
entrypoint = "bash"

[[module]]
name = "bash"
source = "./bash.wasm"
abi = "wasi"

[[command]]
name = "bash"
module = "bash"

[[command]]
name = "sh"
module = "bash"

Option 2 - put it in the command

[package]
name = "sharrattj/bash"
version = "1.2.3"

[[module]]
name = "bash"
source = "./bash.wasm"
abi = "wasi"

[[command]]
name = "bash"
module = "bash"
entrypoint = true

[[command]]
name = "sh"
module = "bash"

Option 3 - create a separate section

[package]
name = "sharrattj/bash"
version = "1.2.3"

[[module]]
name = "bash"
source = "./bash.wasm"
abi = "wasi"

[[command]]
name = "bash"
module = "bash"

[[command]]
name = "sh"
module = "bash"

[defaults]
entrypoint = "bash"