Replace value in json during run time

user_5488998 0
Viewed 13806

I am trying to replace value on run time in json i.e.

Old

{
  "containerDefinitions": [{
    "name": "containername",
    "image": "myimage",
    "memory": 512,
    "cpu": 1,
    "essential": true,
    "portMappings": [{
      "hostPort": 80,
      "containerPort": 80,
      "protocol": "tcp"
    }]
  }],
  "volumes": [],
  "family": "containername"
}

New should be 

{
  "containerDefinitions": [{
    "name": "containername",
    "image": "new image",
    "memory": 512,
    "cpu": 1,
    "essential": true,
    "portMappings": [{
      "hostPort": 80,
      "containerPort": 80,
      "protocol": "tcp"
    }]
  }],
  "volumes": [],
  "family": "containername"
}
  • Old value: - "image": "myimage"
  • New Value: - "image": "new image"

I want to do in bash. Is there any best way to do? Can we do through jq?

bash
6 Answers

Given that linux does not by itself allow redirection to the same file, you can use the sponge utility from moreutils package 

- apt update && apt install -y moreutils
- jq '.json_label="json_value"' file.json | sponge file.json

This will truly allow in line replacement;

user_24097930

If python is reliably present, then you can use embedded python like so:

  • setup multiline string

  • execute and fail on error

    #!/usr/bin/evn bash
# python as multi line string

read -r -d '' PYSCRIPT << ENDPY
import json
import os
jsonfile = 'daemon.json'
data = {}
if os.path.exists(jsonfile):
    data = json.load(open(jsonfile))
data["booleanVar"] = True
data["stringVar"] = "foo"
with open(jsonfile, 'w') as fp:
    json.dump(data, fp)
ENDPY

# execute python and fail on error

echo "$PYSCRIPT" |python - || exit 1
user_99500
Related