Glyn Normington glyn

This is a short, fun series of articles on some of the parts of Rust that newcomers find most confusing. Thanks @eeeeeta for taking the time to make things clearer!

Doubtless the title was inspired by Learn You Some Erlang for Great Good! and Learn You a Haskell for Great Good!.

Superseded by a book.

	apiVersion: apiextensions.k8s.io/v1beta1
	kind: CustomResourceDefinition
	metadata:
	name: certificaterequests.cert-manager.io
	spec:
	additionalPrinterColumns:
	- JSONPath: .status.conditions[?(@.type=="Ready")].status
	name: Ready
	type: string
	- JSONPath: .spec.issuerRef.name

	$ GO111MODULE=off go run github.com/projectriff/k8s-manifest-scanner/cmd/k8s-manifest-scanner scan https://raw.githubusercontent.com/pivotal/kpack/master/samples/experimental/store.yaml
	[
	"cloudfoundry/cnb:bionic",
	"gcr.io/cf-build-service-public/node-engine-buildpackage@sha256:95ff756f0ef0e026440a8523f4bab02fd8b45dc1a8a3a7ba063cefdba5cb9493",
	"gcr.io/cf-build-service-public/npm-buildpackage@sha256:5058ceb9a562ec647ea5a41008b0d11e32a56e13e8c9ec20c4db63d220373e33"
	]

	...
	---
	apiVersion: apps/v1
	kind: Deployment
	metadata:
	name: kpack-controller
	namespace: kpack
	spec:
	replicas: 1
	selector:

	apiVersion: apiextensions.k8s.io/v1beta1
	kind: CustomResourceDefinition
	metadata:
	name: certificaterequests.cert-manager.io
	spec:
	additionalPrinterColumns:
	- JSONPath: .status.conditions[?(@.type=="Ready")].status
	name: Ready
	type: string
	- JSONPath: .spec.issuerRef.name

	cat scratch/deployment.yaml \| ./gojq --yaml-input --yaml-output '(..\|.spec?.containers\|values[].image\| select(. == "nginx"))\|="banana"'
	apiVersion: apps/v1
	kind: Deployment
	metadata:
	name: sample-deployment
	spec:
	template:
	spec:
	containers:
	- image: banana

	$ ./sheaf init --bundle-path scratch/example --bundle-name example
	$ ./sheaf manifest add --bundle-path scratch/example -f scratch/deployment.yaml
	Adding manifest from scratch/deployment.yaml
	$ cat scratch/deployment.yaml
	apiVersion: apps/v1
	kind: Deployment
	metadata:
	name: sample-deployment
	spec:
	template:

	echo '["a"]' \| ./src/wrap_in_docker.sh ./src/one_off.sh '$[0,0]'
	Sending build context to Docker daemon 75.26kB
	Step 1/24 : FROM ubuntu:20.10
	...
	Step 24/24 : RUN apt-get install -y --no-install-recommends ruby
	---> Using cache
	---> 25adaf4f6bcb
	Successfully built 25adaf4f6bcb
	Successfully tagged json-path-comparison:latest
	[1/4] (cd implementations/Bash_JSONPath.sh && npm install) && echo > implementations/Bash_JSONPath.sh/build/node_modules_installed