Module `wasm-wasi-component` is not found among available application modules

[flynneva]

Roughly following the tutorial here to use unit to serve my own rust yew app I am seeing this error when trying to load the configuration:

{
  "error": "Invalid configuration.",
  "detail": "The module to run \"wasm-wasi-component\" is not found among the available application modules."
}

As a total newbie here, a few questions that may have super simple answers:

1. How can you list the available application modules that my unitc server supports?
2. How do you install / add additional application modules to unitc?

Somewhat related would be a suggestion for an article on how to take a trunk build --release built site and deploying it in production with unit. I don't think there are any really good tutorials to do this yet out there in the world and could be a great use case for unit.

[ac000]

Hi,

I'm not aware of a quick way to list the available language modules.

The best way I know is to look in the modules directory, where this is will depend on where you got Unit from.

Perhaps unitd --version will show you... E.g

$ /path/to/unitd --version
unit version: 1.33.0
configured as ./configure --prefix=/opt/unit --modulesdir=/opt/unit/modules --statedir=/opt/unit/state --runstatedir=/opt/unit --tmpdir=/var/tmp --logdir=/opt/unit --log=/opt/unit/unit.log --pid=/opt/unit/unit.pid --control=unix:/opt/unit/control.unit.sock

Here we see the modules directory set to --modulesdir=/opt/unit/modules and I have a few modules in there

$ ls -l /opt/unit/modules
total 15860
-rwxr-xr-x 1 andrew andrew   593200 Apr 26  2023 python.unit.so
-rwxr-xr-x 1 andrew andrew   268040 Apr 12  2023 skel.unit.so
-rwxr-xr-x 1 andrew andrew   306808 Mar 14 14:31 wasm.unit.so
-rwxr-xr-x 1 andrew andrew 15068536 Mar 14 14:31 wasm_wasi_component.unit.so

wasm_wasi_component.unit.so is the one you're interested in.

My Unit is built from source. If you installed Unit via your package manager, then each language module is likely in its own package.

For example on Fedora 39 we have

unit.x86_64
unit-devel.x86_64
unit-go.noarch
unit-jsc-common.noarch
unit-jsc17.x86_64
unit-perl.x86_64
unit-php.x86_64
unit-python312.x86_64
unit-ruby.x86_64
unit-wasm.x86_64

The unit-wasm package contains the wasm-wasi-component module.

$ sudo dnf repoquery -l unit-wasm.x86_64
Last metadata expiration check: 0:00:57 ago on Mon 01 Apr 2024 15:43:50 BST.
/usr/lib/.build-id
/usr/lib/.build-id/18
/usr/lib/.build-id/18/e435b54d8219b9ef41ef6bf4d13454df44a7b7
/usr/lib/.build-id/18/e435b54d8219b9ef41ef6bf4d13454df44a7b7.1
/usr/lib/.build-id/31
/usr/lib/.build-id/31/efc65dfefe2e9d6720315024843e8cc3c32ada
/usr/lib/.build-id/48
/usr/lib/.build-id/48/d8753714c2be0d8fa051ed273797f6ef0fd808
/usr/lib/.build-id/77
/usr/lib/.build-id/77/8556ce4c7cabaf69fba1b8813aa4979d543ad1
/usr/lib64/libwasmtime.so
/usr/lib64/unit/debug-modules/wasm.unit.so
/usr/lib64/unit/debug-modules/wasm_wasi_component.unit.so
/usr/lib64/unit/modules/wasm.unit.so
/usr/lib64/unit/modules/wasm_wasi_component.unit.so
/usr/share/doc/unit-wasm
/usr/share/doc/unit-wasm/COPYRIGHT
/usr/lib/.build-id
/usr/lib/.build-id/2f
/usr/lib/.build-id/2f/6b26f01091470114724721378fb6de5c4b31b0
/usr/lib/.build-id/45
/usr/lib/.build-id/45/00826d63f8a733b1ee03ad1c648cddbf16df4b
/usr/lib/.build-id/45/00826d63f8a733b1ee03ad1c648cddbf16df4b.1
/usr/lib/.build-id/54
/usr/lib/.build-id/54/94970b203abc3a9a352abba5cdf6fb83ba7784
/usr/lib/.build-id/db
/usr/lib/.build-id/db/1855b7dda1a68d8bc4acd1aa8df954ffa0fa03
/usr/lib64/libwasmtime.so
/usr/lib64/unit/debug-modules/wasm.unit.so
/usr/lib64/unit/debug-modules/wasm_wasi_component.unit.so
/usr/lib64/unit/modules/wasm.unit.so
/usr/lib64/unit/modules/wasm_wasi_component.unit.so
/usr/share/doc/unit-wasm
/usr/share/doc/unit-wasm/COPYRIGHT

[lcrilly]

Unit logs the modules it discovers at startup. You can run unitd in the foreground to see this output directly. Here's what it looks like on my Mac (with lots of modules loaded):

$ unitd --no-daemon --control unix:/tmp/t --log /dev/stderr
2024/04/01 18:54:50 [warn] 10857#14455726 Unit is running unprivileged, then it cannot use arbitrary user and group.
2024/04/01 18:54:50 [info] 10857#14455726 unit 1.32.1 started
2024/04/01 18:54:50 [info] 10858#14455728 discovery started
2024/04/01 18:54:50 [notice] 10858#14455728 module: java 11.0.22 "/opt/homebrew/lib/unit/modules/java.unit.so"
2024/04/01 18:54:50 [notice] 10858#14455728 module: perl 5.38.2 "/opt/homebrew/lib/unit/modules/perl.unit.so"
2024/04/01 18:54:50 [notice] 10858#14455728 module: php 8.3.4 "/opt/homebrew/lib/unit/modules/php.unit.so"
2024/04/01 18:54:50 [notice] 10858#14455728 module: python 3.12.2 "/opt/homebrew/lib/unit/modules/python3.unit.so"
2024/04/01 18:54:50 [notice] 10858#14455728 module: ruby 3.3.0 "/opt/homebrew/lib/unit/modules/ruby.unit.so"
2024/04/01 18:54:50 [notice] 10858#14455728 module: wasm 0.1 "/opt/homebrew/lib/unit/modules/wasm.unit.so"
2024/04/01 18:54:50 [notice] 10858#14455728 module: wasm-wasi-component 0.1 "/opt/homebrew/lib/unit/modules/wasm_wasi_component.unit.so"
…
^C

Note you'll need to manually ^C to quit.

If you scroll to the platform you're using at https://unit.nginx.org/installation/ there are instructions for how to install the individual modules.

[flynneva]

@ac000 @lcrilly big thank you to both of you! 🙏🏼 exactly what I was looking for.