#### Setting your own Docker configuration file (advanced)
There might be cases where you need to provide the complete [Docker configuration file](https://docs.docker.com/engine/reference/commandline/cli/#configuration-files):
* need to declare authentication credentials for other registries than the 2 predefined ones (snapshot & release),
* need to declare a [credentials store](https://docs.docker.com/engine/reference/commandline/login/#credentials-store)(ex: in order to [publish to Amazon ECR](https://github.com/GoogleContainerTools/kaniko#pushing-to-amazon-ecr) with Kaniko for instance),
* need to declare [proxies](https://docs.docker.com/engine/reference/commandline/cli/#automatic-proxy-configuration-for-containers),
* ...
If you are in one of those cases, you will need to use the `DOCKER_CONFIG_FILE` variable, expected to declare the path to your custom Docker configuration file (JSON). You may:
* leave the default value (`.docker/config.json`) or override it to some alternate location in your project repository and create the file **without any secret in it** using our dynamic variables replacement (see below),
* or override it as a GitLab project variable of type [File](https://docs.gitlab.com/ee/ci/variables/#cicd-variable-types), possibly inlining your secret credentials in it.
| `DOCKER_CONFIG_FILE` | Path to the Docker configuration file (JSON) | `.docker/config.json` |
Moreover, this file supports **dynamic environment variables replacement**.
That means it may contain references to other environment variables (in the format `${variable_name}`) that will be dynamically replaced
by the template before evaluation.
In addition to you own defined variables, you may use the following variables (provided and managed by the template):
*`${docker_snapshot_authent_token}`: the authentication token required by the snapshot registry (computed from configured `DOCKER_REGISTRY_SNAPSHOT_USER` / `DOCKER_REGISTRY_SNAPSHOT_PASSWORD` variables)
*`${docker_snapshot_registry_host}`: the snapshot registry host (based on the configured `DOCKER_SNAPSHOT_IMAGE ` variable)
*`${docker_release_authent_token}`: the authentication token required by the release registry (computed from configured `DOCKER_REGISTRY_RELEASE_USER` / `DOCKER_REGISTRY_RELEASE_PASSWORD` variables)
*`${docker_release_registry_host}`: the release registry host (based on the configured `DOCKER_RELEASE_IMAGE ` variable)
Example 1: Docker configuration file inlined in the project repository (`.docker/config.json`) with **dynamic variables replacement**:
```json
{
"auths":{
"${docker_snapshot_registry_host}":{
"auth":"${docker_release_authent_token}"
},
"${docker_release_registry_host}":{
"auth":"${docker_snapshot_authent_token}"
},
"my-readonly-repo-to-pull":{
"auth":"${MY_OWN_REGISTRY_TOKEN}"
}
}
}
```
This file uses:
* template-managed `${docker_snapshot_authent_token}`, `${docker_snapshot_registry_host}`, `${docker_release_authent_token}` and `${docker_release_registry_host}` variables,
* the user-defined `${MY_OWN_REGISTRY_TOKEN}` (:information_source: an authentication token can be obtained with command `echo "user:password" | base64` and then be stored as a masked GitLab CI/CD project variable).
Example 2: Docker configuration file declared as a GitLab project variable of type [File](https://docs.gitlab.com/ee/ci/variables/#cicd-variable-types) with **dynamic variables replacement**:
```json
{
"auths":{
"$${docker_snapshot_registry_host}":{
"auth":"$${docker_release_authent_token}"
},
"$${docker_release_registry_host}":{
"auth":"$${docker_snapshot_authent_token}"
},
"my-readonly-repo-to-pull":{
"auth":"ZG9ja2VyZHVkZTpnb3RjaGEh"
}
}
}
```
This file uses:
* template-managed `${docker_snapshot_authent_token}`, `${docker_snapshot_registry_host}`, `${docker_release_authent_token}` and `${docker_release_registry_host}` variables (:warning: mind the double `$$` to prevent GitLab from [trying to evaluate the variable](https://docs.gitlab.com/ee/ci/variables/index.html#use-the--character-in-variables)),
* the user-defined authentication may be inlined as a GitLab project variable is a place safe enough to store secrets.
## Multi Dockerfile support
This template supports building multiple Docker images from a single Git repository.
"description":"The Docker [context path](https://docs.docker.com/engine/reference/commandline/build/#build-with-path) (working directory) - _only set if you want a context path different from the Dockerfile location_",
"advanced":true
},
{
"name":"DOCKER_CONFIG_FILE",
"description":"Path to the [Docker configuration file](https://docs.docker.com/engine/reference/commandline/cli/#sample-configuration-file) (JSON)",
# for retro-compatibility (deprecated & undocumented)
DOCKER_DOCKERFILE_PATH:"."
DOCKER_FILE:"$DOCKER_DOCKERFILE_PATH/Dockerfile"
DOCKER_CONFIG_FILE:".docker/config.json"
# When testing a Docker Health (test stage), how long (in seconds) wait for the HealthCheck status (https://docs.docker.com/engine/reference/builder/#healthcheck)
