Passing YAML content to a command in a bash function - bash

Question

I'm currently writing a bash script and struggling with something that looked fairly simple at first.
I'm trying to create a function that calls a kubectl (Kubernetes) command. The command is expecting the path to a file as an argument although I'd like to pass the content itself (multiline YAML text). It works in the shell but can't make it work in my function. I've tried many things and the latest looks like that (it's just a subset of the the YAML content):
#!/bin/bash
AGENT_NAME="default"
deploy_agent_statefulset() {
kubectl apply -n default -f - $(cat <<- END
kind: ConfigMap
metadata:
name: $AGENT_NAME
apiVersion: v1
data:
agent.yaml: |
metrics:
wal_directory: /var/lib/agent/wal
END
)
}
deploy_agent_statefulset
The initial command that works in the shell is the following.
cat <<'EOF' | NAMESPACE=default /bin/sh -c 'kubectl apply -n $NAMESPACE -f -'
kind: ConfigMap
...
I'm sure I m doing a lot of things wrong - keen to get some help
Thank you.
name: grafana-agent

Answer 1

In your function, you didn't contruct stdin properly :
#!/bin/bash
AGENT_NAME="default"
deploy_agent_statefulset() {
kubectl apply -n default -f - <<END
kind: ConfigMap
metadata:
name: $AGENT_NAME
apiVersion: v1
data:
agent.yaml: |
metrics:
wal_directory: /var/lib/agent/wal
END
}
deploy_agent_statefulset

Answer 2

this one should work:
#!/bin/bash
AGENT_NAME="default"
deploy_agent_statefulset() {
cat << EOF | kubectl apply -n default -f -
apiVersion: v1
kind: ConfigMap
metadata:
name: $AGENT_NAME
data:
agent.yaml: |
metrics:
wal_directory: /var/lib/agent/wal
EOF
}
deploy_agent_statefulset
To point out what is wrong in your yaml which are all indentations,
you don't need to add the indentations in the beginning
name goes under metadata, so it needs to be intended.
agent.yaml is the key, for the data in the ConfigMap, so it needs to be intended as well