Trouble using rules_docker and the next.js example

[pwalker]

I'm trying to combine the next.js example with the rules_docker with the e2e/ example, and I'm running into an issue. I've created an example repo with a new folder with my attempt: https://github.com/pwalker/bazel-examples/tree/main/next.js_docker.

There's 1 big difference between the pnpm workspace setup and the main next.js example, and that's where I've moved the next.js dependency from the monorepo root into the apps/alpha package.json. I've also removed the individual build files from the pages/, styles/ and public/ directory in favor of globbing.

I think the import bit is the container_image target:

js_image_layer(
    name = "layers",
    binary = ":next_start",
    root = "/app",
    visibility = ["//visibility:__pkg__"],
)

# ...

container_image(
    name = "image",
    architecture = "amd64",  # or arm64

    # Since js_binary depends on bash we have to bring in a base image that has bash
    base = "@debian_amd64//image",  # or "@debian_arm64//image", if you are on an arm machine
    # This is going to be /{root of js_image_layer}/{package_name()}/{name of js_binary}
    cmd = ["/app/apps/alpha/next_start"],
    entrypoint = ["bash"],
    layers = [
        ":app_layer",
        ":node_modules_layer",
    ],
    # TODO: does this need a workdir?
    # workdir = "/app/apps/alpha/next_start.runfiles/__main__",
)

Based on the layout I'm seeing in dive, I've been playing around with setting the workdir, but that messes up how the next_start.sh tries to follow the chdir argument.

Without a workdir, I get:

> docker run bazel/apps/alpha:image
/app/apps/alpha/next_start.runfiles/__main__/apps/alpha/next_start.sh: line 400: cd: apps/alpha: No such file or directory

And when I try to set the workdir to the folder that has the next.config.js file, I get something that looks more promising:

> docker run bazel/apps/alpha:image


Starting js_run_devserver //apps/alpha:next_start
Syncing...
60 files synced in 10 ms
Running './node_modules/.bin/next ' in /tmp/js_run_devserver-GEEsib/__main__/apps/alpha


ready - started server on 0.0.0.0:3000, url: http://localhost:3000
Error: > Couldn't find a `pages` directory. Please create one under the project root
    at Object.findPagesDir (/app/apps/alpha/next_start.runfiles/__main__/node_modules/.aspect_rules_js/next@13.0.5_biqbaboplfbrettd7655fr4n2y/node_modules/next/dist/lib/find-pages-dir.js:86:19)
    at new DevServer (/app/apps/alpha/next_start.runfiles/__main__/node_modules/.aspect_rules_js/next@13.0.5_biqbaboplfbrettd7655fr4n2y/node_modules/next/dist/server/dev/next-dev-server.js:104:59)
    at NextServer.createServer (/app/apps/alpha/next_start.runfiles/__main__/node_modules/.aspect_rules_js/next@13.0.5_biqbaboplfbrettd7655fr4n2y/node_modules/next/dist/server/next.js:140:20)
    at /app/apps/alpha/next_start.runfiles/__main__/node_modules/.aspect_rules_js/next@13.0.5_biqbaboplfbrettd7655fr4n2y/node_modules/next/dist/server/next.js:155:42
    at async NextServer.prepare (/app/apps/alpha/next_start.runfiles/__main__/node_modules/.aspect_rules_js/next@13.0.5_biqbaboplfbrettd7655fr4n2y/node_modules/next/dist/server/next.js:130:24)
    at async /app/apps/alpha/next_start.runfiles/__main__/node_modules/.aspect_rules_js/next@13.0.5_biqbaboplfbrettd7655fr4n2y/node_modules/next/dist/cli/next-dev.js:330:13
child tool process exited with code 1

From what I can tell, all the files it needs are in the image. Any ideas?

[pwalker]

OK, big LOL on this one. Just after I typed this all up, I realized it was right in front of me. In this line of the output with the workdir, it doesn't look like I'm passing the start argument to the next CLI:

Running './node_modules/.bin/next ' in /tmp/js_run_devserver-GEEsib/__main__/apps/alpha

I changed my container_image rule to include it, and it seems to work!

container_image(
    name = "image",
    architecture = "amd64",  # or arm64

    # Since js_binary depends on bash we have to bring in a base image that has bash
    base = "@debian_amd64//image",  # or "@debian_arm64//image", if you are on an arm machine
    # This is going to be /{root of js_image_layer}/{package_name()}/{name of js_binary}
    cmd = [
        "/app/apps/alpha/next_start",
        "start", # <--- this thing
    ],
    entrypoint = ["bash"],
    layers = [
        ":app_layer",
        ":node_modules_layer",
    ],
    # I think it for sure needs a workdir
    workdir = "/app/apps/alpha/next_start.runfiles/__main__",
)

Closing as solved!