minecraft-assets/data/minecraft/recipes/redstone_lamp.json

{
  "type": "minecraft:crafting_shaped",
  "category": "redstone",
  "key": {
    "G": {
      "item": "minecraft:glowstone"
    },
    "R": {
      "item": "minecraft:redstone"
    }
  },
  "pattern": [
    " R ",
    "RGR",
    " R "
  ],
  "result": {
    "item": "minecraft:redstone_lamp"
  }
}