See also: Extension
Contents:
View all the available extensions
To view all the available Rockcraft / Charmcraft extensions, run the rockcraft list-extensions / charmcraft list-extensions command. Sample session:
$ charmcraft list-extensions
Extension name Supported bases Experimental bases
---------------- ----------------- --------------------
flask-framework ubuntu@22.04
See more: Rockcraft |
rockcraft list-extensions,charmcraft list-extensions
View details about the extension in use
Suppose you’ve initialised a rock / charm with a profile that comes with an extension (currently, flask-framework), and your rockcraft.yaml / charmcraft.yaml > extensions lists this extension.
See sample context
$ mkdir my-flask-app-k8s
$ cd my-flask-app-k8s/
$ charmcraft init --profile flask-framework
Charmed operator package file and directory tree initialised.
Now edit the following package files to provide fundamental charm metadata
and other information:
charmcraft.yaml
src/charm.py
README.md
user@ubuntu:~/my-flask-app-k8s$ ls -R
.:
charmcraft.yaml requirements.txt src
./src:
charm.py
$ cat charmcraft.yaml
# This file configures Charmcraft.
# See https://juju.is/docs/sdk/charmcraft-config for guidance.
name: my-flask-app-k8s
type: charm
bases:
- build-on:
- name: ubuntu
channel: "22.04"
run-on:
- name: ubuntu
channel: "22.04"
# (Required)
summary: A very short one-line summary of the flask application.
# (Required)
description: |
A comprehensive overview of your Flask application.
extensions:
- flask-framework
# Uncomment the integrations used by your application
# requires:
# mysql:
# interface: mysql_client
# limit: 1
# postgresql:
# interface: postgresql_client
# limit: 1
To view details about what that extension is adding to your rock / charm, set the ROCKCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS / CHARMCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS to 1, then run the rockcraft expand-extensions / charmcraft expand-extensions command. For example:
CHARMCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS=1 charmcraft expand-extensions
See effect given sample context
$ CHARMCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS=1 charmcraft expand-extensions
*EXPERIMENTAL* extension 'flask-framework' enabled
name: my-flask-app-k8s
summary: A very short one-line summary of the flask application.
description: |
A comprehensive overview of your Flask application.
parts:
charm:
source: .
charm-entrypoint: src/charm.py
charm-binary-python-packages: []
charm-python-packages: []
charm-requirements:
- requirements.txt
charm-strict-dependencies: false
plugin: charm
type: charm
bases:
- build-on:
- name: ubuntu
channel: '22.04'
run-on:
- name: ubuntu
channel: '22.04'
actions:
rotate-secret-key:
description: Rotate the flask secret key. Users will be forced to log in again.
This might be useful if a security breach occurs.
assumes:
- k8s-api
containers:
flask-app:
resource: flask-app-image
peers:
secret-storage:
interface: secret-storage
provides:
metrics-endpoint:
interface: prometheus_scrape
grafana-dashboard:
interface: grafana_dashboard
requires:
logging:
interface: loki_push_api
ingress:
interface: ingress
limit: 1
resources:
flask-app-image:
type: oci-image
description: flask application image.
config:
options:
webserver-keepalive:
type: int
description: Time in seconds for webserver to wait for requests on a Keep-Alive
connection.
webserver-threads:
type: int
description: Run each webserver worker with the specified number of threads.
webserver-timeout:
type: int
description: Time in seconds to kill and restart silent webserver workers.
webserver-workers:
type: int
description: The number of webserver worker processes for handling requests.
flask-application-root:
type: string
description: Path in which the application / web server is mounted. This configuration
will set the FLASK_APPLICATION_ROOT environment variable. Run `app.config.from_prefixed_env()`
in your Flask application in order to receive this configuration.
flask-debug:
type: boolean
description: Whether Flask debug mode is enabled.
flask-env:
type: string
description: What environment the Flask app is running in, by default it's 'production'.
flask-permanent-session-lifetime:
type: int
description: Time in seconds for the cookie to expire in the Flask application
permanent sessions. This configuration will set the FLASK_PERMANENT_SESSION_LIFETIME
environment variable. Run `app.config.from_prefixed_env()` in your Flask application
in order to receive this configuration.
flask-preferred-url-scheme:
type: string
default: HTTPS
description: Scheme for generating external URLs when not in a request context
in the Flask application. By default, it's "HTTPS". This configuration will
set the FLASK_PREFERRED_URL_SCHEME environment variable. Run `app.config.from_prefixed_env()`
in your Flask application in order to receive this configuration.
flask-secret-key:
type: string
description: The secret key used for securely signing the session cookie and
for any other security related needs by your Flask application. This configuration
will set the FLASK_SECRET_KEY environment variable. Run `app.config.from_prefixed_env()`
in your Flask application in order to receive this configuration.
flask-session-cookie-secure:
type: boolean
description: Set the secure attribute in the Flask application cookies. This
configuration will set the FLASK_SESSION_COOKIE_SECURE environment variable.
Run `app.config.from_prefixed_env()` in your Flask application in order to
receive this configuration.
See more:
rockcraft expand-extensions,charmcraft expand-extensions