python - ScannerError: mapping values are not allowed here in "config.yaml"?

Question

I want to configure a yaml file for all project configuration, but this below file I am not able to read/parse it?

Here is the error I am getting, What am I doing wrong here?

ScannerError: mapping values are not allowed here
  in "config.yaml", line 7, column 13

---

appName: test
logLevel: WARN


TESTER:
    ENVIRONMENT: staging
      CONFIG:
        DATABASE:
          HOST: 2123.3123.2112.12
          USERNAME: x
          PASSWORD: y
          DB: Q
        CLASSIFIER:
          IMG_WIDTH: 380
          IMG_HEIGHT: 380
          HOST: 0.0.0.0:3201

question from:https://stackoverflow.com/questions/65936747/scannererror-mapping-values-are-not-allowed-here-in-config-yaml

Answer 1

The Issue is with the indentation of your yaml. ENVIRONMENT is having different indent compared to CONFIG, which is in next line.

You can use any online validators like http://www.yamllint.com or https://codebeautify.org/yaml-validator to validate your yaml files.

This is valid YAML:

appName: test
logLevel: WARN


TESTER:
    ENVIRONMENT: staging
    CONFIG:
        DATABASE:
            HOST: 2123.3123.2112.12
            USERNAME: x
            PASSWORD: y
            DB: Q
        CLASSIFIER:
            IMG_WIDTH: 380
            IMG_HEIGHT: 380
            HOST: 0.0.0.0:3201

UPDATE:
If you want to use multiple configurations, then generally list of maps is used with a name attribute like below.
It is a good practice to give NAME attribute, even if there is only one config.

appName: test
logLevel: WARN

TESTER:
  - NAME: staging
    ENVIRONMENT: staging
    CONFIG:
      DATABASE:
        HOST: 2123.3123.2112.12
        USERNAME: x
        PASSWORD: 'y'
        DB: Q
      CLASSIFIER:
        IMG_WIDTH: 380
        IMG_HEIGHT: 380
        HOST: '0.0.0.0:3201'
  - NAME: production
    ENVIRONMENT: production
    CONFIG:
      DATABASE:
        HOST: 2123.3123.2112.14
        USERNAME: xP
        PASSWORD: yP
        DB: Q
      CLASSIFIER:
        IMG_WIDTH: 380
        IMG_HEIGHT: 380
        HOST: '0.0.0.0:3201'

In this YAML, he similarly uses two maps under deploy