opa build -t wasm doesn't generate bundle.tar.gz

[onelittlenightmusic]

opa build doesn't seem to be able to generate bundle.tar.gz after 0.27.0. Before 0.26.0, it works well.

Expected Behavior

opa build -t wasm -e hello/hello hello.rego
(no error and generated bundle.tar.gz)

Actual Behavior

Using v0.27.0 or later

bin/opa0.27.0 build -t wasm -e hello/hello hello.rego
error: compiler ABI version not in capabilities (have [], want {1 1})

Using v0.26.0, this command works.

bin/opa0.26.0 build -t wasm -e hello/hello hello.rego
(no error)

Steps to Reproduce the Problem

• Create a file hello.rego

package hello

default hello = ""

hello = rtn {
    m := input.message
    rtn := concat("", ["hello, ", m])
}

• Following the document, run this command.
  https://www.openpolicyagent.org/docs/latest/wasm/#compiling-policies

opa  build -t wasm -e hello/hello hello.rego

Environment

• MacOS 11.2.3 (big sur)
• Each version of binaries were separately downloaded from release page.
  Thank you, all the community!!

Additional Info

I am not sure if this is related to #3264 or not..

[srenatus]

You'll have to provide a capabilities json of the target version. Your cli executable doesn't have wasm enabled so it won't build what it cannot run.

[onelittlenightmusic]

@srenatus Thank you so much for your advice! You saved my day. I downloaded the following file to the same directory.
https://github.com/open-policy-agent/opa/blob/master/capabilities/v0.27.1.json
And I ran this command.

opa build -t wasm -e hello/hello hello.rego --capabilities v0.27.1.json

Finally, I got bundle.tar.gz correctly. I appreciate that.

I guess a description about necessity of capacilities json can be added in the following document. What do you think about it?
https://www.openpolicyagent.org/docs/latest/wasm/#compiling-policies

# download
curl -L -o  v0.27.1.json https://raw.githubusercontent.com/open-policy-agent/opa/master/capabilities/v0.27.1.json
opa build -t wasm -e example/allow example.rego --capabilities v<version>.json

[srenatus]

Yup there's definitely a documentation need here. Would you want to contribute a note there or would you prefer if I did that? 😃

[srenatus]

Nevermind the docs, we'll fix this in code 😅

[onelittlenightmusic]

@srenatus Thank you for your comment! I am sorry for late response. If I have a chance, I would like to contribute. I am not familiar with document structure, but I found a likely document in the following document. Is this correct? If so, I will try PR in a few days.
https://github.com/open-policy-agent/opa/blob/master/docs/content/wasm.md
I feel like that the concept of capabilities is vaster than wasm itself. I guess in the future, there might be a documentation need of vast concept of capabilities (is there already such a document?). Anyway, I think at least the description in wasm is needed, so I will make PR.

[srenatus]

Anyway, I think at least the description in wasm is needed, so I will make PR.

Thank you! As hinted on above, I'll put a PR out for changing the default behaviour here. (Next thing, tomorrow at the latest.)

[onelittlenightmusic]

Oh, I see. Great! Default behavior change is much better. There will be no need to amend document. No need to hurry. Thank you for all!