/actix-qrcode

Simple demo app with the Actix Web microframework

Primary LanguageRust

Simple demo web app in Rust, compatible with Knative Serving

The app exposes the an API endpoint under / which accepts a content string as query parameter. It returns an image (by default a PNG) in the body with a QRCode that encodes the string.

Optionally one can also pass the following query parameters:

  • render: how to render the image, either png (defaut) or svg.
  • size: the size of the raster image in pixels (ignored when render=svg)
  • shape: the shape of the QRCode modules: square (default), roundedsquare, circle, diamond, vertical or horizontal (beware that not all client applications will be able to correctly decode a QRCode with an exotic module shape).
  • embed: whether to embed an image in the QRcode (boolean, default is false). The default image can be replaced with a custom svg image by means of the env variable EMBEDDED_IMG_PATH.

Example requests with curl:

curl localhost:8080/?content=the-1st-string-to-be-encoded&size=1000&embed=true

curl localhost:8080/?content=the-2nd-string-to-be-encoded&render=svg&shape=roundedsquare

Knative Serving

The endpoints /health/readiness and /health/liveness are also provided for compatibility with Knative Serving.

By default the service listens to port 8080. It can be modified via the environment variable PORT. The IP address to which the service binds is by default 0.0.0.0, but it can be likewise modified via BIND_ADDRESS.

The provided Dockerfile can be used to build a container image based on Fedora 38. Alternatively, using the file Dockerfile.ubi9 will base the image on UBI 9, which is a better choice for a production deployment, e.g. on OpenShift.

To deploy your image as a Knative service, e.g. on OpenShift Serverless, use e.g.

kn service create qrcode \
    --image your-repo/qrcode \
    --port 8080

Pipelines as Code

A file .tekton/pipelinerun.yaml is provided for the Pipelines as Code feature of Tekton. To enable it, follow the instructions provided by the previous link. It provides three tasks, executed sequentially:

  1. fetch-repository (with git-clone)
  2. build-image (with buildah)
  3. kn-service-apply (with kn)

This fetches the code, builds the container image and finally deploys the Knative service to the Kubernetes or OpenShift cluster.

Tested on OCP 4.14 with Pipelines 1.15

NB1: An easier alternative would have been to use Knative Functions with Rust and remote deploy, but with the approach exemplified in this repo, we have full control over the image build, which is actually faster than with buildpack and produces a much leaner image!

NB2: On OpenShift, the pod that runs the kn Tekton Task might not have the necessary permissions to execute kn service apply. You may have to create a ClusterRole and bind it with a ClusterRoleBinding to the pipeline service account. See crb.yaml for an example of how to achieve this (change the namespace according to your environment).