jq

Summary

Item	Value
API name	jq
source OCI image	alpine:3.22 + jq
per-job resource ceiling	1 vCPU, 256 MiB

The vCPU and RAM ceiling exists to prevent abuse; libkrun memory is elastic and the host only pays for what the guest touches.

Warmup

apk add jq: the base image does not ship jq. The package is installed in the build VM and baked into the ext4. See Images.

How the code is executed

The main file (the first in files) is the filter, executed with jq --null-input -f <file>. With --null-input, the filter's initial input is null; to read the JSON from the job's stdin, use input (one value) or inputs (all of them). Everything runs in a directory under /tmp (tmpfs), in a fresh VM destroyed at the end of the job, with no network.

Building the image

rc image build --stack jq

Example

curl -s http://127.0.0.1:8080/api/v1/run \
  -H 'Content-Type: application/json' \
  -d '{
    "language": "jq",
    "files": [
      {"name": "main.jq", "content": "input | .a + .b\n"}
    ],
    "stdin": "{\"a\": 40, \"b\": 2}"
  }'

Expected stdout: 42.