When you want to process a JSON file in Jenkins pipeline, you can do in various ways

• Pipeline Utility Steps readJSON
• jq
• JSON Parser in Python, NodeJS. etc

This article will focus on the problem with jq vs Jenkins sh since it introducing some interesting problem.

Sample Data

file.json

{
    "lorem": {
        "key": "Lorem Ipsum",
        "dash-key": "Lorem Ipsum",
        "underscore_key": "Lorem Ipsum",
    }
}

In the jq, a syntax to get the JSON value from a key is

$ cat file.json | jq -r .lorem.key
Lorem Ipsum
$ cat file.json | jq -r .lorem.underscore_key
Lorem Ipsum

But, it will have a problem when your JSON key contains "-" dash.

$ cat file.json | jq -r .lorem.dash-key
jq: error: key/0 is not defined at <top-level>, line 1:
.lorem.dash-key
jq: 1 compile error

With some limitation with jq, a key string contains dash - have to combine pattern with single-quote and double-quote when query. Possible in many pattern to get a value.

Dash Issue with jq Github Issue, Stack Overflow

$cat file.json | jq -r '.lorem."dash-key"'
Lorem Ipsum

$cat file.json | jq -r .lorem.'"dash-key"'
Lorem Ipsum

$cat file.json | jq -r '.lorem["dash-key"]'
Lorem Ipsum

$cat file.json | jq -r .lorem.\"dash-key\"
Lorem Ipsum

When we bring the jq query into Jenkins with a key name as a variable. It will lead to next problem, as Jenkins have some weird way to manipulating string with single-quote and double-quote in sh function.

Fun read Adventures with escaping quotes in Jenkins and Gist of weird escape on Jenkins

Then, we need to escape double-quote with Jenkins sh and jq with this pattern \\\"

SOME_KEY = "dash-key"
value = sh(returnStdout: true, script: "cat file.json | jq -r .lorem.\\\"${SOME_KEY}\\\"").trim()