json-update

json-update updates the values of specified keys in any JSON file.

Configuration

Name	Type	Required	Description
path	string	Y	Path to a JSON file. This path is relative to the temporary workspace that Kargo provisions for use by the promotion process.
updates	[]object	Y	The details of changes to be applied to the file. At least one must be specified.
updates[].key	string	Y	The key to update within the file. For nested values, use a JSON dot notation path. See sjson documentation for supported syntax.
updates[].value	any	Y	The new value for the key. Typically specified using an expression. Supports strings, numbers, booleans, arrays, and objects.

Output

Name	Type	Description
commitMessage	string	A description of the change(s) applied by this step. Typically, a subsequent git-commit step reference this output and aggregate this commit message fragment with other like it to build a comprehensive commit message that describes all changes.

Examples

Common Usage

In this example, a JSON file's values are updated according to changes in a container image tag. After cloning the repository and clearing the output directory, the json-update step updates the image.tag field in configs/settings.json to match the tag of the image being promoted. This demonstrates how to modify nested JSON values using dot notation (similar to how you would reference nested object properties).

This pattern is commonly used when managing configuration files that need to stay synchronized with deployed container versions.

info

For more information on imageFrom and expressions, see the Expressions documentation.

vars:
- name: gitRepo
  value: https://github.com/example/repo.git
steps:
- uses: git-clone
  config:
    repoURL: ${{ vars.gitRepo }}
    checkout:
    - commit: ${{ commitFrom(vars.gitRepo).ID }}
      path: ./src
    - branch: stage/${{ ctx.stage }}
      create: true
      path: ./out
    - uses: git-clear
      config:
        path: ./out
- uses: json-update
  config:
    path: configs/settings.json
    updates:
    - key: image.tag
      value: ${{ imageFrom("my/image").Tag }}
# Render manifests to ./out, commit, push, etc...