### Update 2020 for WSL2

If you're using this with WSL2, docker images will be maintained inside of your [wsl drive][1] available at **`\\wsl$\`** per this [github issue][2]:


* **Windows**: `\\wsl$\docker-desktop-data\mnt\wsl\docker-desktop-data\data\docker\volumes`
* **Linux**: `sudo ls /mnt/wsl/docker-desktop-data/data/docker/volumes`

[1]: https://devblogs.microsoft.com/commandline/whats-new-for-wsl-in-windows-10-version-1903/
[2]: https://github.com/microsoft/WSL/issues/4176

NOTE: Am super new to both Windows and Docker

The tutorial I've been using says that they are under `/var/lib/docker/containers` if we're using Linux, but I can't seem to find that on my Windows machine.

Thanks!

Where are docker images and containers stored when we use it with Windows?

## Using Docker Config

Since this is fundamentally a docker questions, not a bash question, you don't even need an alias.  Docker CLI allows you to customize these commands in your own config file! From this great tip from [Container 42][1]:

1. Create or find your docker config file (if you've ever used [`docker login`][2] it should already be created.

    ```none
    ~/.docker/config.json
    ```

2. Then add the default formatting for docker to use every time it runs the `ps` command as a top level property in the config:

    ```json
    {
        "psFormat": "table {{.Image}}\t{{.Names}}\t{{.Ports}}\t{{.Status}}",
    }
    ```

3. Then just run [`docker ps`][3] like normal:

   [![docker ps][4]][4]

### PS Format

Docker uses [go templates][10] and has a [list of the valid placeholders][11]:

| Command           | Description                                       |
| ----------------- | ------------------------------------------------- |
| **`.ID`**         | Container ID                                      |
| **`.Image`**      | Image ID                                          |
| **`.Command`**    | Quoted command                                    |
| **`.CreatedAt`**  | Time when the container was created.              |
| **`.RunningFor`** | Elapsed time since the container was started.     |
| **`.Ports`**      | Exposed ports.                                    |
| **`.Status`**     | Container status.                                 |
| **`.Size`**       | Container disk size.                              |
| **`.Names`**      | Container names.                                  |
| **`.Labels`**     | All labels assigned to the container.             |
| **`.Label`**      | Value of a specific label for this container.     |
| **`.Mounts`**     | Names of the volumes mounted in this container.   |
| **`.Networks`**   | Names of the networks attached to this container. |

### Alternative Solutions / Threads


* Github Issues
  * [Default "docker ps" output is too wide][5]
  * [docker ps output is so long it's unreadable][6]
* Third Party Commands
  * [**ctop**][7] - Top-like interface for container metrics
  * [**docker-pretty-ps**][8] - beautiful, colored, long output log
  * [**dockerps**][9] - A better docker ps


  [1]: https://container42.com/2016/03/27/docker-quicktip-7-psformat/
  [2]: https://docs.docker.com/engine/reference/commandline/login/
  [3]: https://docs.docker.com/engine/reference/commandline/ps/
  [4]: https://i.stack.imgur.com/gJUVJ.png
  [5]: https://github.com/moby/moby/issues/7477
  [6]: https://github.com/docker/for-linux/issues/279
  [7]: https://github.com/bcicen/ctop
  [8]: https://github.com/politeauthority/docker-pretty-ps
  [9]: https://github.com/sadorlovsky/dockerps
  [10]: https://golang.org/pkg/text/template/
  [11]: https://docs.docker.com/engine/reference/commandline/ps/#formatting

The `docker` command has a `ps` sub-command that emits very long lines:

    $ docker ps -a
    CONTAINER ID        IMAGE                             COMMAND                  CREATED             STATUS                      PORTS                                                                                                                                                                                                                                                                                                        NAMES
    6e8ec8a16da4        waisbrot/wait:latest              "/wait"                  4 minutes ago       Exited (0) 4 minutes ago                                                                                                                                                                                                                                                                                                                 wait-for-janus-test
    9dbf0739561f        whoop/downsampler:master          "./run.bash"             4 minutes ago       Up 4 minutes                0.0.0.0:32855->4369/tcp, 0.0.0.0:32854->9100/tcp, 0.0.0.0:32853->9101/tcp, 0.0.0.0:32852->9102/tcp, 0.0.0.0:32851->9103/tcp, 0.0.0.0:32850->9104/tcp, 0.0.0.0:32849->9105/tcp, 0.0.0.0:32848->9106/tcp, 0.0.0.0:32847->9107/tcp, 0.0.0.0:32846->9108/tcp, 0.0.0.0:32845->9109/tcp, 0.0.0.0:32844->9110/tcp   metrics-downsampler-test
    6cf56623bb48        whoop/janus:master                "./start.bash"           4 minutes ago       Up 4 minutes                0.0.0.0:32843->80/tcp                                                                                                                                                                                                                                                                                        janus-test
    882b50303d54        whoop/recalculator:master         "./run.bash"             4 minutes ago       Exited (1) 4 minutes ago                                                                                                                                                                                                                                                                                                                 internum-test

It can be instructed to output only specific columns:

    docker ps --format "table {{.Image}}\t{{.Names}}\t{{.Ports}}\t{{.Status}}"

I'd like to be able to say `docker ps` and get the `--format "table..."` argument added on for me. Is there a nice way to do this? 

I know I could say

    alias dp='docker ps --format ...'

but I'd prefer to keep the sub-command. 

I'm using zsh as my shell.

Can I alias a subcommand? (shortening the output of `docker ps`)

### Best Approach - Resilient App Starts

While docker *does* support startup dependencies, they officially recommend updating your app start logic to test for the availability of external dependencies and retry.  This has lots of benefits for robust applications that may restart in the wild on the fly in addition to circumventing the race condition in `docker compose up`

### `depends_on` & `service_healthy` - Compose 1.27.0<sup>+</sup>

`depends_on` is back in docker compose v1.27.0+ (was deprecated in v3) in the [Compose Specification](https://docs.docker.com/compose/compose-file/#depends_on)


Each service should also implement a `service_healthy` check to be able to report if it's fully setup and ready for downstream dependencies.

```yml
version: '3.0'
services:
  php:
    build:
      context: .
      dockerfile: tests/Docker/Dockerfile-PHP
    depends_on:
      redis:
        condition: service_healthy
  redis:
    image: redis
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 1s
      timeout: 3s
      retries: 30
```


### `wait-for-it.sh`

The recommended approach from docker according to their docs on [Control startup and shutdown order in Compose][1] is to download [`wait-for-it.sh`][0] which takes in the `domain:port` to poll and then executes the next set of commands if successful.  

```yml
version: "2"
services:
  web:
    build: .
    ports:
      - "80:8000"
    depends_on:
      - "db"
    command: ["./wait-for-it.sh", "db:5432", "--", "python", "app.py"]
  db:
    image: postgres
```


**Note**: This requires overriding the startup command of the image, so make sure you know what wanted to pass to maintain parity of the default startup.


### Further Reading

* [Docker Compose wait for container X before starting Y][2]
* [Difference between links and depends_on in docker_compose.yml][3]
* [How can I wait for a docker container to be up and running?][4]
* [Docker Compose Wait til dependency container is fully up before launching][5]
* [depends_on doesn't wait for another service in docker-compose 1.22.0][6]

[0]: https://github.com/vishnubob/wait-for-it/blob/master/wait-for-it.sh
[1]: https://docs.docker.com/compose/startup-order/
[2]: https://stackoverflow.com/q/31746182/1366033
[3]: https://stackoverflow.com/q/35832095/1366033
[4]: https://stackoverflow.com/q/21183088/1366033
[5]: https://stackoverflow.com/q/55502234/1366033
[6]: https://stackoverflow.com/q/52699899/1366033

I have the following **docker-compose**, where I need to wait for the service **jhipster-registry** to be up and accepting connections before starting **myprogram-app**.

I tried the healtcheck way, following the official doc https://docs.docker.com/compose/compose-file/compose-file-v2/ 

    version: '2.1'
    services:
        myprogram-app:
            image: myprogram
            mem_limit: 1024m
            environment:
                - SPRING_PROFILES_ACTIVE=prod,swagger
                - EUREKA_CLIENT_SERVICE_URL_DEFAULTZONE=http://admin:$${jhipster.registry.password}@jhipster-registry:8761/eureka
                - SPRING_CLOUD_CONFIG_URI=http://admin:$${jhipster.registry.password}@jhipster-registry:8761/config
                - SPRING_DATASOURCE_URL=jdbc:postgresql://myprogram-postgresql:5432/myprogram
                - JHIPSTER_SLEEP=0
                - SPRING_DATA_ELASTICSEARCH_CLUSTER_NODES=myprogram-elasticsearch:9300
                - JHIPSTER_REGISTRY_PASSWORD=53bqDrurQAthqrXG
                - EMAIL_USERNAME
                - EMAIL_PASSWORD
            ports:
                - 8080:8080
            networks:
              - backend
            depends_on:
              - jhipster-registry:
                  "condition": service_started
              - myprogram-postgresql
              - myprogram-elasticsearch
        myprogram-postgresql:
            image: postgres:9.6.5
            mem_limit: 256m
            environment:
                - POSTGRES_USER=myprogram
                - POSTGRES_PASSWORD=myprogram
            networks:
              - backend
        myprogram-elasticsearch:
            image: elasticsearch:2.4.6
            mem_limit: 512m
            networks:
              - backend
        jhipster-registry:
            extends:
                file: jhipster-registry.yml
                service: jhipster-registry
            mem_limit: 512m
            ports:
                - 8761:8761
            networks:
              - backend
            healthcheck:
              test: "exit 0"
    networks:
      backend:
        driver: "bridge"

but I get the following error when running `docker-compose up`:

    ERROR: The Compose file './docker-compose.yml' is invalid because:
    services.myprogram-app.depends_on contains {"jhipster-registry": {"condition": "service_started"}}, which is an invalid type, it should be a string

Am I doing something wrong, or this feature is no more supported? How to achieve this sync between services?

**Updated version**

    version: '2.1'
    services:
        myprogram-app:
            image: myprogram
            mem_limit: 1024m
            environment:
                - SPRING_PROFILES_ACTIVE=prod,swagger
                - EUREKA_CLIENT_SERVICE_URL_DEFAULTZONE=http://admin:$${jhipster.registry.password}@jhipster-registry:8761/eureka
                - SPRING_CLOUD_CONFIG_URI=http://admin:$${jhipster.registry.password}@jhipster-registry:8761/config
                - SPRING_DATASOURCE_URL=jdbc:postgresql://myprogram-postgresql:5432/myprogram
                - JHIPSTER_SLEEP=0
                - SPRING_DATA_ELASTICSEARCH_CLUSTER_NODES=myprogram-elasticsearch:9300
                - JHIPSTER_REGISTRY_PASSWORD=53bqDrurQAthqrXG
                - EMAIL_USERNAME
                - EMAIL_PASSWORD
            ports:
                - 8080:8080
            networks:
              - backend
            depends_on:
              jhipster-registry:
                condition: service_healthy
              myprogram-postgresql:
                condition: service_started
              myprogram-elasticsearch:
                condition: service_started
            #restart: on-failure
        myprogram-postgresql:
            image: postgres:9.6.5
            mem_limit: 256m
            environment:
                - POSTGRES_USER=myprogram
                - POSTGRES_PASSWORD=tuenemreh
            networks:
              - backend
        myprogram-elasticsearch:
            image: elasticsearch:2.4.6
            mem_limit: 512m
            networks:
              - backend
        jhipster-registry:
            extends:
                file: jhipster-registry.yml
                service: jhipster-registry
            mem_limit: 512m
            ports:
                - 8761:8761
            networks:
              - backend
            healthcheck:
              test: ["CMD", "curl", "-f", "http://jhipster-registry:8761", "|| exit 1"]
              interval: 30s
              retries: 20
              #start_period: 30s
    networks:
      backend:
        driver: "bridge"

The updated version gives me a different error, 

    ERROR: for myprogram-app  Container "8ebca614590c" is unhealthy.
    ERROR: Encountered errors while bringing up the project.

saying that the container of jhipster-registry is unhealthy, but it's reachable via browser. How can I fix the command in the healthcheck to make it work?