Document updated on Dec 7, 2021

Generating a Docker artifact

If you use containers, the recommended approach is to write your own Dockerfile and deploy an immutable artifact (embedding the config).

In its simplified form would be:

FROM krakend/krakend-ee:2.0
COPY krakend.json /etc/krakend/krakend.json
# Uncomment with Enterprise image:
# COPY LICENSE /etc/krakend/LICENSE

A more real-life example illustrates below a combination of the check command with a multi-stage build to compile a flexible configuration in a Dockerfile:

FROM krakend/krakend-ee:2.0 as builder
ARG ENV=prod

COPY krakend.tmpl .
COPY config .

## Save temporary file to /tmp to avoid permission errors
RUN FC_ENABLE=1 \
    FC_OUT=/tmp/krakend.json \
    FC_PARTIALS="/etc/krakend/partials" \
    FC_SETTINGS="/etc/krakend/settings/$ENV" \
    FC_TEMPLATES="/etc/krakend/templates" \
    krakend check -d -t -c krakend.tmpl

# The linting needs the final krakend.json file
RUN krakend check -c /tmp/krakend.json --lint

FROM krakend/krakend-ee:2.0
COPY --from=builder --chown=krakend /tmp/krakend.json .
# Uncomment with Enterprise image:
# COPY LICENSE /etc/krakend/LICENSE

The Dockerfile above has two stages: The check command compiles the template krakend.tmpl and any included sub-template inside and outputs (FC_OUT) the resulting /tmp/krakend.json file. The krakend.json file is the only addition to the final Docker image.

The example above assumes you have a file structure like this:

.
├── config
│   ├── partials
│   ├── settings
│   │   ├── prod
│   │   │   └── env.json
│   │   └── test
│   │       └── env.json
│   └── templates
│       └── some.tmpl
├── Dockerfile
└── krakend.tmpl

Generate the skeleton above with:

mkdir -p config/{partials,settings,templates}
mkdir -p config/settings/{prod,test}
touch Dockerfile krakend.tmpl

Now the only missing step to generate the image, is to build it, making sure that the environment argument matches our folder inside the settings folder:

$docker build --build-arg ENV=prod -t mykrakend .

The resulting image, including your configuration, weighs around 80MB.