Using wkhtmltopdf on fly.io

1

Hello, I’m creating a web site that needs to generate PDF files. I decided to use wkhtmltopdf (through pdf-generator library). When trying to deploy my application to fly.io I’m getting an error because it needs the wkhtmltopdf executable. Any way of doing this? is it even possible?
Thanks.

1 Like
2

What kind of app are you running? You should be able to add wkhtmltopdf to your app image. If you’re using a Dockerfile it might even be easy.

3

Thanks Kurt, your response pointed me to the right direction and I got it working now.

The app is an internal invoice system for my company.

Thanks again for your help. Fly.io is indeed great.

4

How did you solve it?

1 Like
5

This took me a long time to get working due to all the dependencies wkhtmltopdf has. Here’s my Dockerfile:

# syntax = docker/dockerfile:1

# Make sure RUBY_VERSION matches the Ruby version in .ruby-version and Gemfile
ARG RUBY_VERSION=3.2.2
ARG BUNDLER_VERSION=2.4.12
FROM ruby:$RUBY_VERSION-slim as base

LABEL fly_launch_runtime="rails"

# Rails app lives here
WORKDIR /rails

# Set production environment
ENV RAILS_ENV="production" \
    BUNDLE_WITHOUT="development:test" \
    BUNDLE_DEPLOYMENT="1"

# Update gems and bundler
RUN gem update --system --no-document && \
    gem install -N bundler -v "${BUNDLER_VERSION}"

# Install packages needed to install nodejs
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y curl && \
    rm -rf /var/lib/apt/lists /var/cache/apt/archives

# Install Node.js
ARG NODE_VERSION=16.13.2
ENV PATH=/usr/local/node/bin:$PATH
RUN curl -sL https://github.com/nodenv/node-build/archive/master.tar.gz | tar xz -C /tmp/ && \
    /tmp/node-build-master/bin/node-build "${NODE_VERSION}" /usr/local/node && \
    rm -rf /tmp/node-build-master

# Latest releases available at https://github.com/aptible/supercronic/releases
ENV SUPERCRONIC_URL=https://github.com/aptible/supercronic/releases/download/v0.2.24/supercronic-linux-amd64 \
    SUPERCRONIC=supercronic-linux-amd64 \
    SUPERCRONIC_SHA1SUM=6817299e04457e5d6ec4809c72ee13a43e95ba41

RUN curl -fsSLO "$SUPERCRONIC_URL" \
    && echo "${SUPERCRONIC_SHA1SUM}  ${SUPERCRONIC}" | sha1sum -c - \
    && chmod +x "$SUPERCRONIC" \
    && mv "$SUPERCRONIC" "/usr/local/bin/${SUPERCRONIC}" \
    && ln -s "/usr/local/bin/${SUPERCRONIC}" /usr/local/bin/supercronic

# You might need to change this depending on where your crontab is located
COPY crontab crontab

# Throw-away build stage to reduce size of final image
FROM base as build

# Install packages needed to build gems and node modules
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y build-essential git libpq-dev node-gyp pkg-config python-is-python3

# Install yarn
ARG YARN_VERSION=1.22.10
RUN npm install -g yarn@$YARN_VERSION

# Build options
ENV PATH="/usr/local/node/bin:$PATH"

# Install application gems
COPY --link Gemfile Gemfile.lock ./
RUN bundle install --without development test && \
    rm -rf ~/.bundle/ $BUNDLE_PATH/ruby/*/cache $BUNDLE_PATH/ruby/*/bundler/gems/*/.git

# Install node modules
# COPY --link package.json yarn.lock ./
# RUN yarn install --frozen-lockfile

# Copy application code
COPY --link . .

# Adjust binfiles to set current working directory
RUN grep -l '#!/usr/bin/env ruby' /rails/bin/* | xargs sed -i '/^#!/aDir.chdir File.expand_path("..", __dir__)'

# Precompiling assets for production without requiring secret RAILS_MASTER_KEY
# RUN SECRET_KEY_BASE=DUMMY ./bin/rails assets:precompile

# Final stage for app image
FROM base

# Install packages needed for deployment
RUN apt-get update -qq && \
    apt-get install --no-install-recommends -y postgresql-client && \
    rm -rf /var/lib/apt/lists /var/cache/apt/archives

# Install wkhtmltopdf
RUN apt update && apt -y upgrade
RUN apt install -y wget
RUN wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.buster_amd64.deb
RUN apt install -y \
    fontconfig \
    libfreetype6 \
    libjpeg62-turbo \
    libpng16-16 \
    libx11-6 \
    libxcb1 \
    libxext6 \
    libxrender1 \
    xfonts-75dpi \
    xfonts-base

RUN apt install -y ./wkhtmltox_0.12.6-1.buster_amd64.deb \
    && rm ./wkhtmltox_0.12.6-1.buster_amd64.deb \
    && chmod +x /usr/local/bin/wkhtmltopdf
        
# Run and own the application files as a non-root user for security
ARG UID=1000 \
    GID=1000
RUN groupadd -f -g $GID rails && \
    useradd -u $UID -g $GID rails --home /rails --shell /bin/bash
USER rails:rails

# Copy built artifacts: gems, application
COPY --from=build /usr/local/bundle /usr/local/bundle
COPY --from=build --chown=rails:rails /rails /rails

# Deployment options
ENV RAILS_LOG_TO_STDOUT="1" \
    RAILS_SERVE_STATIC_FILES="true"

# Entrypoint prepares the database.
ENTRYPOINT ["/rails/bin/docker-entrypoint"]

# Start the server by default, this can be overwritten at runtime
EXPOSE 3000
CMD ["./bin/rails", "server"]

The relevant portion:

# Install wkhtmltopdf
RUN apt update && apt -y upgrade
RUN apt install -y wget
RUN wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.buster_amd64.deb
RUN apt install -y \
    fontconfig \
    libfreetype6 \
    libjpeg62-turbo \
    libpng16-16 \
    libx11-6 \
    libxcb1 \
    libxext6 \
    libxrender1 \
    xfonts-75dpi \
    xfonts-base

RUN apt install -y ./wkhtmltox_0.12.6-1.buster_amd64.deb \
    && rm ./wkhtmltox_0.12.6-1.buster_amd64.deb \
    && chmod +x /usr/local/bin/wkhtmltopdf
1 Like
6

You could also try this:

RUN apt install -y --no-install-recommends wkhtmltopdf
1 Like
7

I agree with @ben-io

@elpavohombre you should have been able to do this with:

bin/rails generate dockerfile --add=wkhtmltopdf

Did you do this by calling wkhtmltopdf directly (e.g., using backtics or Open3)? Or did you use a gem? If the latter, I’d like to make this easier for people going forward by either automatically detecting the presence of a dependent gem and adding wkhtmltopdf for you. I already do this with grover (and puppeteer in general).