Passing a string containing curly brackets to helm caused: Error: failed parsing --set data: key

Question

${CLIENT_ID} and ${CLIENT_SECRET} are both sourced from a yaml based properties file e.g

CLIENT_ID: 11111111-1111-1111-1111-111111111111
CLIENT_SECRET: '{aes}AM+JYP8t9ga1m6s111x1fjdfePL10v90RmbgWFdOjVdD/wlnszAbJad8aOI4qqMv6eSGaW2nfTF4PG2OYH+rx9K052TXNP6PGAAcRph9pl11'

using:

PROPERTIES_FILE="properties.yaml"
CLIENT_ID=$(yq r "${PROPERTIES_FILE}" CLIENT_ID)
CLIENT_SECRET=$(yq r "${PROPERTIES_FILE}" CLIENT_SECRET)

and then passed into my helm command for deploying my app:

echo ${CLIENT_ID}
# 11111111-1111-1111-1111-111111111111
echo ${CLIENT_SECRET}
# {aes}AM+JYP8t9ga1m6s111x1fjdfePL10v90RmbgWFdOjVdD/wlnszAbJad8aOI4qqMv6eSGaW2nfTF4PG2OYH+rx9K052TXNP6PGAAcRph9pl11

helm upgrade -i --debug  --namespace mynamespace release \
-f "charts/app/values.yaml" \
--set "app.configmap.dependancy.client_id=${CLIENT_ID}" \
--set "app.configmap.dependancy.client_secret=${CLIENT_SECRET}" \
"charts/app/"

charts/app/values.yaml contains:

app:
  ..
  configmap:
    dependancy:
      client_id: ""
      client_secret: ""

The problem is, I get this error when running the helm command:

Error: failed parsing --set-string data: key "AM+JYP8t9ga1m6s111x1fjdfePL10v90RmbgWFdOjVdD/wlnszAbJad8aOI4qqMv6eSGaW2nfTF4PG2OYH+rx9K052TXNP6PGAAcRph9pl11" has no value
No resources found.

Any idea why the prefixed {aes} is causing problems when passed into helm like this? The command works if I remove the {aes} prefix.

Answer 1

Helm tries to make it possible to pass some structured data in using --set and that's tripping you up here. In particular,

Lists can be expressed by enclosing values in { and }. For example, --set name={a, b, c} translates to [a list of a, b, and c].

So if you --set 'key={aes}AM+JYP8...', the {aes} part looks like that list syntax but then there's things after it that Helm doesn't understand.

You can backslash-escape the curly braces, though that's a little tricky to do in shell syntax. There's a --set-string option (documented in the Helm 2 documentation but still present in Helm 3) that might be able to do this. Possibly the most straightforward path, though, is to write out your own custom YAML values file:

#!/bin/sh
PROPERTIES_FILE="properties.yaml"
CLIENT_ID=$(yq r "${PROPERTIES_FILE}" CLIENT_ID)
CLIENT_SECRET=$(yq r "${PROPERTIES_FILE}" CLIENT_SECRET)

cat >values.tmp.yaml <<EOF
app:
  configmap:
    dependancy:
      client_id: "${CLIENT_ID}"
      client_secret: "${CLIENT_SECRET}"
EOF

helm upgrade -i --debug --namespace mynamespace release \
  -f values.tmp.yaml charts/app

(You can have multiple helm install -f options if you need to. The chart's values.yaml is read in automatically, and is overridden by command-line options.)