Add custom Dockerfile workflow example

[alexjurkiewicz]

As per #101.

[dschep]

Good idea! But why not use the dockerFile option? Then you can skip the build step! and the config would be

custom:
  pythonRequirements:
    dockerFile: ./Dockerfile

[alexjurkiewicz]

Hm, actually the Docker support doesn't quite do what I want. I want to add the file /usr/lib64/mysql57/libmysqlclient.so.1020 to my zipfile (in the root directory). It's accessible in the Docker image, but Pip (obviously) doesn't copy it to /var/task during pip install....

Current build process:

1. Build custom image with pip dependencies
2. Run the image with a bind mount to .serverless/ to /var/task, and command pip install ...

After running pip install, I want to copy some files from the image to .serverless/requirements. Does this plugin have a supported way to do so?

[alexjurkiewicz]

I've updated the docs to handle both cases:

1. Adding build-time OS dependencies
2. Adding run-time OS dependencies

If there's a better way to implement 2 than "copy them into your repo" I'm all ears. Couldn't figure it out myself though :(

[dschep]

There's no reason AFAIK not to still use the lambci build image as the base, and it make the dockerfile smaller

FROM lambci/lambda:build-python3.6

# Install your dependencies
yum -y install mysql-devel

[dschep]

As for step2. that's fine 👍

[alexjurkiewicz]

Thanks for the feedback. Unfortunately I had issues installing packages into lambci/lambda:build-python3.6. Here's an example Dockerfile:

FROM lambci/lambda:build-python3.6
RUN yum install -y mysql-devel
WORKDIR /var/task

docker build . output:

Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM lambci/lambda:build-python3.6
 ---> 408b3aae7c81
Step 2/3 : RUN yum install -y mysql-devel
[...]
Running transaction
  Installing : mysql55-libs-5.5.57-1.18.amzn1.x86_64                        1/5
  Installing : mysql-config-5.5.57-1.18.amzn1.x86_64                        2/5
  Installing : mysql55-5.5.57-1.18.amzn1.x86_64                             3/5
  Installing : mysql55-devel-5.5.57-1.18.amzn1.x86_64                       4/5
  Installing : mysql-devel-5.5-1.6.amzn1.noarch                             5/5

Rpmdb checksum is invalid: dCDPT(pkg checksums): mysql-config.x86_64 0:5.5.57-1.18.amzn1 - u

The command '/bin/sh -c yum install -y mysql-devel' returned a non-zero code: 1

There are some workarounds in this thread of the issue:

• yum install yum-plugin-ovh
• rpm --rebuilddb && touch /var/lib/rpm/*
• Append || true to each yum command.

Only the last one helped. If you like, I can change the example to use that (with a comment referencing the bug) with the lambci container?

[dschep]

Ah, I see. That's good enough reason for me.