Cache writing and permissions in a Lambda Docker container

[soundstep]

Version: Deno 1.45.2

I'm applying this guide: https://docs.deno.com/runtime/tutorials/aws_lambda/

I've got some permissions issue in the container. I can see what kind of problem this is, but what would be an elegant way of solving? A chmod? Using DENO_DIR?

The AWS Lambda log:

Download https://registry.npmjs.org/@octokit/webhooks-methods/-/webhooks-methods-5.1.0.tgz
Download https://registry.npmjs.org/@octokit/openapi-webhooks-types/-/openapi-webhooks-types-8.3.0.tgz
Download https://registry.npmjs.org/@octokit/openapi-types/-/openapi-types-22.2.0.tgz
Download https://registry.npmjs.org/@octokit/endpoint/-/endpoint-10.1.1.tgz
error: JSR package manifest for '@hono/hono' failed to load. Read-only file system (os error 30) (for '/home/sbx_user1051/.cache/deno/deps/https/jsr.io')
Check the permission of the directory.
at file:///var/task/lib/fe-core-merge-queue-project/server/middleware.ts:2:31
EXTENSION   Name: lambda-adapter    State: Ready    Events: []
INIT_REPORT Init Duration: 2155.65 ms   Phase: invoke   Status: error   Error Type: Runtime.ExitError
START RequestId: 5768476b-cd75-437c-9563-6cbfb9ae2fc4 Version: $LATEST
RequestId: 5768476b-cd75-437c-9563-6cbfb9ae2fc4 Error: Runtime exited with error: exit status 1
Runtime.ExitError
END RequestId: 5768476b-cd75-437c-9563-6cbfb9ae2fc4
REPORT RequestId: 5768476b-cd75-437c-9563-6cbfb9ae2fc4  Duration: 2196.08 ms    Billed Duration: 2197 ms    Memory Size: 128 MB Max Memory Used: 18 MB

Dockerfile:

# Set up the base image
FROM public.ecr.aws/awsguru/aws-lambda-adapter:0.8.4 AS aws-lambda-adapter
FROM denoland/deno:bin-1.45.2 AS deno_bin
FROM debian:bookworm-20230703-slim AS deno_runtime
COPY --from=aws-lambda-adapter /lambda-adapter /opt/extensions/lambda-adapter
COPY --from=deno_bin /deno /usr/local/bin/deno
ENV PORT=8000
EXPOSE 8000

# Copy the function code
WORKDIR "/var/task"
COPY . /var/task

# Warmup caches
RUN timeout 10s deno run -A main.ts || [ $? -eq 124 ] || exit 1

CMD ["deno", "run", "-A", "main.ts"]

[lucacasonato]

@soundstep Can you try add a RUN deno cache main.ts right after the # Warmup caches comment? It is possible that warming up this script (with downloading of dependencies), takes more than 10 seconds.

We can adjust that in the guide if that is the case.

[soundstep]

@lucacasonato

This gave me the exact same error:

# Warmup caches
RUN timeout 10s deno run -A main.ts || [ $? -eq 124 ] || exit 1
RUN deno cache main.ts

This seem to have fixed it:

# Warmup caches
ENV DENO_DIR=$HOME/.cache/deno
RUN timeout 10s deno run -A main.ts || [ $? -eq 124 ] || exit 1
RUN deno cache main.ts

I guess deno just couldn't write in /home/sbx_user1051/.cache/deno.

Does that fix make sense?

Side question: Does RUN deno cache main.ts work because it runs for the first time? It doesn't do anything locally unless I do deno cache -r main.ts.

[lucacasonato]

Ah yes, that makes sense. DENO_DIR is computed relative to the user's home directory. If the build user and the runtime user are different, the DENO DIR will be different. I am updating the docs to recommend specifying a DENO_DIR explicitly: https://github.com/denoland/docs/pull/850.

deno cache ... does not look like it does anything after the first time, because the files will already be cached. It only prints out new files it is downloading. deno cache -r forcibly re-downloads all files, so that is why you are seeing output for that.

[soundstep]

Great, thanks for the additional info!

[soundstep]

@lucacasonato FYI, side note: https://github.com/maxday/lambda-perf/pull/1492