# dgoss

dgoss is a convenience wrapper around goss that aims to bring the simplicity of goss to docker containers.

## Examples and Tutorials
* [blog tutorial](https://medium.com/@aelsabbahy/tutorial-how-to-test-your-docker-image-in-half-a-second-bbd13e06a4a9) - Introduction to dgoss tutorial
* [video tutorial](https://youtu.be/PEHz5EnZ-FM) - Same as above, but in video format
* [dgoss-examples](https://github.com/aelsabbahy/dgoss-examples) - Repo containing examples of using dgoss to validate docker images

## Installation
#### Linux:

Follow the goss [installation instructions](https://github.com/goss-org/goss#installation)

#### Mac OSX

Since goss runs on the target container, dgoss can be used on a Mac OSX system by doing the following:
```
# Install dgoss
curl -L https://raw.githubusercontent.com/goss-org/goss/master/extras/dgoss/dgoss -o /usr/local/bin/dgoss
chmod +rx /usr/local/bin/dgoss

# Download desired goss version to your preferred location (e.g. v0.3.6)
curl -L https://github.com/goss-org/goss/releases/download/v0.3.6/goss-linux-amd64 -o ~/Downloads/goss-linux-amd64

# Set your GOSS_PATH to the above location
export GOSS_PATH=~/Downloads/goss-linux-amd64

# Use dgoss
dgoss edit ...
dgoss run ...
```


## Usage

`dgoss [run|edit] <docker_run_params>`


### Run

Run is used to validate a docker container. It expects a `./goss.yaml` file to exist in the directory it was invoked from. In most cases one can just substitute the docker command for the dgoss command, for example:

**run:**

`docker run -e JENKINS_OPTS="--httpPort=8080 --httpsPort=-1" -e JAVA_OPTS="-Xmx1048m" jenkins:alpine`

**test:**

`dgoss run -e JENKINS_OPTS="--httpPort=8080 --httpsPort=-1" -e JAVA_OPTS="-Xmx1048m" jenkins:alpine`


`dgoss run` will do the following:
* Run the container with the flags you specified.
* Stream the containers log output into the container as `/goss/docker_output.log`
  * This allows writing tests or waits against the docker output
* (optional) Run `goss` with `$GOSS_WAIT_OPTS` if `./goss_wait.yaml` file exists in the current dir
* Run `goss` with `$GOSS_OPTS` using `./goss.yaml`


### Edit

Edit will launch a docker container, install goss, and drop the user into an interactive shell. Once the user quits the interactive shell, any `goss.yaml` or `goss_wait.yaml` are copied out into the current directory. This allows the user to leverage the `goss add|autoadd` commands to write tests as they would on a regular machine.

**Example:**

`dgoss edit -e JENKINS_OPTS="--httpPort=8080 --httpsPort=-1" -e JAVA_OPTS="-Xmx1048m" jenkins:alpine`

### Environment vars and defaults
The following environment variables can be set to change the behavior of dgoss.

##### GOSS_PATH
Location of the goss binary to use. (Default: `$(which goss)`)

#####  GOSS_FILE
Name of the goss file to use. (Default: `goss.yaml`)

##### GOSS_OPTS
Options to use for the goss test run. (Default: `--color --format documentation`)

##### GOSS_WAIT_OPTS
Options to use for the goss wait run, when `./goss_wait.yaml` exists. (Default: `-r 30s -s 1s > /dev/null`)

##### GOSS_SLEEP
Time to sleep after running container (and optionally `goss_wait.yaml`) and before running tests. (Default: `0.2`)

##### GOSS_FILES_PATH
Location of the goss yaml files. (Default: `.`)

##### GOSS_VARS
The name of the variables file relative to `GOSS_FILES_PATH` to copy into the
docker container and use for valiation (i.e. `dgoss run`) and copy out of the
docker container when writing tests (i.e. `dgoss edit`). If set, the
`--vars` flag is passed to `goss validate` commands inside the container.
If unset (or empty), the `--vars` flag is omitted, which is the normal behavior.
(Default: `''`).

##### GOSS_FILES_STRATEGY
Strategy used for copying goss files into the docker container. If set to `'mount'` a volume with goss files is mounted and log output is streamed into the container as `/goss/docker_output.log` file. Other strategy is `'cp'` which uses `'docker cp'` command to copy goss files into docker container. With the `'cp'` strategy you lose the ability to write tests or waits against the docker output. The `'cp'` strategy is required especially when docker daemon is not on the local machine. 
(Default `'mount'`)

##### CONTAINER_LOG_OUTPUT
Location of the file that contains tested container logs. Logs are retained only if the variable is set to a non-empty string. (Default `''`)

##### CONTAINER_RUNTIME
Container runtime to use - `docker` or `podman`. Defaults to `docker`. Note that `podman` requires a run command to keep the container running. This defaults to `sleep infinity` in case only an image is passed to `dgoss` commands.
