How to add a mapping in yaml file using python-CodePudding

I have a below yml file samplelambda1.yml

Mappings:
  Environments:
    dev:
        DefaultLambdaConcurrency: '10'
    test:
        DefaultLambdaConcurrency: '10'
    staging:
        DefaultLambdaConcurrency: '10'
    production:
        DefaultLambdaConcurrency: '10'

I have multiple files like samplelambda2,3,4....30

I need to add another mapping to all the yml file with help of python script, how can we do it? I tried string replace but its a complicated operation to open a file and replace multiple lines.

production-new:
    DefaultLambdaConcurrency: '10'

CodePudding user response：

The question shows no effort (no offence but OP should try his approach and post wherever he's stuck) so here is just the hint.

import os

for filename in os.listdir(directory):
    // read each YAML using this: https://stackoverflow.com/a/1774043/5353128
    // add your key value in the read YAML dict.
    // Use yaml.dump() to save the content back to file.

CodePudding user response：

You can handle yaml files in python with pyyaml. To add to the existing yaml you could do something like:

import yaml

with open("file_append.yaml", "r") as fs:
        append_dict = yaml.load(fs, Loader=yaml.SafeLoader)

append_to = ["file_1.yaml"]

for file_name in append_to:
    with open(file_name, "r") as fs:
            target_dict = yaml.load(fs, Loader=yaml.SafeLoader)

    target_dict["Mappings"]["Environments"] = {**target_dict["Mappings"]["Environments"], **append_dict}

    with open(file_name, "w") as fs:
            yaml.dump(target_dict, fs)

Output:

Mappings:
  Environments:
    dev:
      DefaultLambdaConcurrency: '10'
    production:
      DefaultLambdaConcurrency: '10'
    production-new:
      DefaultLambdaConcurrency: '10'
    staging:
      DefaultLambdaConcurrency: '10'
    test:
      DefaultLambdaConcurrency: '10'