docs(docker-compose): Add example README Markdown file

docker-compose/README.md

@@ -13,6 +13,10 @@ project_slug [dir-name]: grafana
 service [grafana]:
 component_list [grafana]: grafana,nginx
 context [ctx]: cncf
+Select build:
+1 - no
+2 - yes
+Choose from 1, 2 [1]: 
 ```
 
 Done, directory structure and files for your next `docker-compose` project are ready for you to hit the ground running.
@@ -60,7 +64,7 @@ Your four answers translate as follows into rendered files.
         ...
     ```
 
-4. The last prompt for a `context` is a generic string to help you distinguish deployments. It can be whatever you want such as for example a team name, here `cncf` which shows up as a preset in an example env file. It defaults to `ctx` just so it can't be empty.
+4. The `context` prompt is a generic string to help you distinguish deployments. It can be whatever you want such as for example a team name, here `cncf` which shows up as a preset in an example env file. It defaults to `ctx` just so it can't be empty.
     ```
     .
     └── grafana
@@ -75,6 +79,12 @@ Your four answers translate as follows into rendered files.
     ...
     ```
 
+5. Prompt `build` is a yes-no question. Cookiecutter will create a `README.md` file with copy-pastable Docker Compose commands pre-filled. If you answer `yes` to this prompt `README.md` will contain an example paragraph that explains the build process along the lines of:
+    ```
+    docker compose ... --profile 'build' build
+    ```
+    Whereas by answering `no` (or just hitting `<Enter>` to accept the default of `no`) no such paragraph will be added to the example Markdown file. Build instructions are only really needed if you need to locally build a derivative image.
+
 Also check out [the Caveats section](#caveats) at the end to learn what this template does not do well.
 
 ## Result

docker-compose/cookiecutter.json

@@ -6,5 +6,6 @@
     "component_list": "{{ cookiecutter.__service_slug }}",
     "__component_list_slug": "{{ cookiecutter.component_list.lower().replace(' ', '_').replace('-', '_') }}",
     "context": "ctx",
-    "__context_slug": "{{ cookiecutter.context.lower().replace(' ', '_').replace('-', '_') }}"
+    "__context_slug": "{{ cookiecutter.context.lower().replace(' ', '_').replace('-', '_') }}",
+    "build": ["no", "yes"]
 }

docker-compose/{{ cookiecutter.__project_slug }}/README.md

@@ -0,0 +1,80 @@
+# {{ cookiecutter.__service_slug.capitalize() }} Docker Compose files
+
+Docker Compose files to spin up an instance of {{ cookiecutter.__service_slug.capitalize() }}.
+
+# How to run
+
+Add a `COMPOSE_ENV` file and save its location as a shell variable along with the location where this repo lives, here for example `/opt/containers/{{ cookiecutter.__project_slug }}` plus all other variables. At [env/fqdn_context.env.example](env/fqdn_context.env.example) you'll find an example environment file.
+
+When everything's ready start {{ cookiecutter.__service_slug.capitalize() }} with Docker Compose, otherwise head down to [Initial setup](#initial-setup) first.
+
+## Environment
+```
+export COMPOSE_DIR='/opt/containers/{{ cookiecutter.__project_slug }}'
+export COMPOSE_CTX='{{ cookiecutter.__context_slug }}'
+export COMPOSE_PROJECT='{{ cookiecutter.__service_slug }}-'"${COMPOSE_CTX}"
+export COMPOSE_FILE="${COMPOSE_DIR}"'/docker-compose.yml'{% if cookiecutter.build == "yes" %}
+export COMPOSE_OVERRIDE="${COMPOSE_DIR%/}"'/docker-compose.override.yml'{% endif %}
+export COMPOSE_ENV=<add accordingly>
+```
+
+{%- if cookiecutter.build == "yes" %}
+
+## Build
+
+```
+docker compose --project-name "${COMPOSE_PROJECT}" --file "${COMPOSE_FILE}" --file "${COMPOSE_OVERRIDE}" --env-file "${COMPOSE_ENV}" --profile 'build' build
+```
+{%- endif %}
+
+## Start
+
+```
+{%- if ',' in cookiecutter.__component_list_slug %}
+docker compose --project-name "${COMPOSE_PROJECT}" --file "${COMPOSE_FILE}" --env-file "${COMPOSE_ENV}" --profile 'full' up --detach
+{%- else %}
+docker compose --project-name "${COMPOSE_PROJECT}" --file "${COMPOSE_FILE}" --env-file "${COMPOSE_ENV}" up --detach
+{%- endif %}
+```
+
+# Initial setup
+
+We're assuming you run Docker Compose workloads with ZFS-based bind mounts. ZFS management, creating a zpool and setting adequate properties for its datasets is out of scope of this document.
+
+## Datasets
+
+Create ZFS datasets and set permissions as needed.
+
+* Parent dateset
+    ```
+    zfs create -o mountpoint=/opt/docker-data 'zpool/docker-data'
+    ```
+
+* Container-specific datasets
+    ```
+{%- if ',' in cookiecutter.__component_list_slug -%}
+{%- set components = cookiecutter.__component_list_slug.split(',') -%}
+{%- for component in components %}
+    zfs create -p 'zpool/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ component }}/data/db'
+    zfs create -p 'zpool/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ component }}/data/logs'
+    zfs create -p 'zpool/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ component }}/config'
+{%- endfor -%}
+{%- else %}
+    zfs create -p 'zpool/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ cookiecutter.__service_slug }}/data/db'
+    zfs create -p 'zpool/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ cookiecutter.__service_slug }}/data/logs'
+    zfs create -p 'zpool/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ cookiecutter.__service_slug }}/config'
+{%- endif %}
+    ```
+    When changing bind mount locations to real ones remember to also update `volumes:` in [docker-compose.yml](docker-compose.yml).
+
+* Change ownership
+    ```
+{%- set components = cookiecutter.__component_list_slug.split(',') -%}
+{% for component in components %}
+{%- if loop.first %}
+    chown -R 1000:1000 '/opt/docker-data/{{ cookiecutter.__service_slug }}-${COMPOSE_CTX}/{{ cookiecutter.__service_slug }}/data'
+{%- endif %}
+{%- endfor %}
+    ```
+
+When done head back up to [How to run](#how-to-run).

docker-compose/{{ cookiecutter.__project_slug }}/docker-compose.yml

@@ -35,6 +35,8 @@ services:
         ports:
             # - "8080:80"
         volumes:
+            # When changing bind mount locations to real ones remember to
+            # also update "Initial setup" section in README.md.
             # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/{{ component }}/data/db:/usr/lib/{{ component }}
             # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/{{ component }}/data/logs:/var/log/{{ component }}
             # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/{{ component }}/config:/etc/{{ component }}
@@ -54,9 +56,11 @@ services:
         ports:
             # - "8080:80"
         volumes:
-            # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/data/db:/usr/lib/{{ cookiecutter.__service_slug }}
-            # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/data/logs:/var/log/{{ cookiecutter.__service_slug }}
-            # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/config:/etc/{{ cookiecutter.__service_slug }}
+            # When changing bind mount locations to real ones remember to
+            # also update "Initial setup" section in README.md.
+            # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/{{ cookiecutter.__service_slug }}/data/db:/usr/lib/{{ cookiecutter.__service_slug }}
+            # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/{{ cookiecutter.__service_slug }}/data/logs:/var/log/{{ cookiecutter.__service_slug }}
+            # - /opt/docker-data/{{ cookiecutter.__service_slug }}-${CONTEXT}/{{ cookiecutter.__service_slug }}/config:/etc/{{ cookiecutter.__service_slug }}
         environment:
             # {{ cookiecutter.__component_list_slug.upper() }}_USER: ${% raw %}{{% endraw %}{{ cookiecutter.__component_list_slug.upper() }}_USER{% raw %}}{% endraw %}
             # {{ cookiecutter.__component_list_slug.upper() }}_PASSWORD: ${% raw %}{{% endraw %}{{ cookiecutter.__component_list_slug.upper() }}_PASSWORD{% raw %}}{% endraw %}