CODEWITHSUNDEEP
pythonyamlruamel.yaml
oHanafi
oHanafi

Reputation: 23

Unwished indent and dash added in first line of yaml file with ruamel.yaml

I am currently using the following code to load in a single-document template YAML file, changing it slightly, and generating (i.e., dumping) different new deployment files. The code looks like this:

import yaml
import copy
import ruamel.yaml
from ruamel.yaml.scalarstring import (DoubleQuotedScalarString as dq, 
                                      SingleQuotedScalarString as sq)
#As requested, below a summary of the functionality of the function define_exp_parameters
def define_exp_parameters(experiment_template, deployments):
    deployment_list = []
    for duration in range(30, 71, 1):
        for cpu_cores in range(1, 4):
                        
            exp_doc[0]['spec']['annotationCheck'] = 'true'
            deployment_list.append(copy.deepcopy(exp_doc)) 
    return deployment_list   
        
testyaml = ruamel.yaml.YAML()
    
with open(template_dir, 'r') as read_file:

    deployments = testyaml.load_all(read_file)
    deployments = list(deployments)
    # define_exp_parameters is used to generate different YAML deployments, each of which are added to a list, which is returned. The list basically consists of x YAML deployment definitions which are later dumped in seperate files.
    deployments = define_exp_parameters(experiment_template, deployments)
            
i = 1
for deployment in deployments:
    with open(save_dir) as created_file:
            
        testyaml.default_flow_style = False
            
        testyaml.dump(deployment, created_file)
            
    i += 1

The template looks like this:

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: teastore-chaos
  namespace: default
spec:
  annotationCheck: 'false'
  engineState: active
  appinfo:
    appns: default
    applabel: app=teastore
    appkind: deployment
  chaosServiceAccount: litmus-admin
  components:
    runner:
      runnerAnnotations:
        sidecar.istio.io/inject: 'false'
  jobCleanUpPolicy: delete
  experiments:
  - name: pod-cpu-hog

This results in files with the following structure:

- apiVersion: litmuschaos.io/v1alpha1
  kind: ChaosEngine
  metadata:
    name: teastore-chaos
    namespace: default
  spec:
    annotationCheck: 'false'
    engineState: active
    appinfo:
      appns: default
      applabel: app=teastore
      appkind: deployment
    chaosServiceAccount: litmus-admin
    components:
      runner:
        runnerAnnotations:
          sidecar.istio.io/inject: 'false'
    jobCleanUpPolicy: delete
    experiments:
    - name: pod-cpu-hog

However, my desired structure would be the following (i.e., same as template):

apiVersion: litmuschaos.io/v1alpha1
kind: ChaosEngine
metadata:
  name: teastore-chaos
  namespace: default
spec:
  annotationCheck: 'false'
  engineState: active
  appinfo:
    appns: default
    applabel: app=teastore
    appkind: deployment
  chaosServiceAccount: litmus-admin
  components:
    runner:
      runnerAnnotations:
        sidecar.istio.io/inject: 'false'
  jobCleanUpPolicy: delete
  experiments:
  - name: pod-cpu-hog

Basically, there shouldn't be a dash in the first line (which, for some reason, is automatically generated/added as it isn't in the original template file) and there shouldn't be an extra first indent in the whole structure (which I think comes along with the dash). I am using ruamel.yaml for dumping as it preserves the explicit single quotations in strings (using the imported package). I have tried looking for similar cases and the ruamel.yaml documentation but I wasn't able to find the reason/solution for this.

Upvotes: 2

Views: 990

Answers (1)

Anthon
Anthon

Reputation: 76578

Without having the source of define_exp_parameters() it is impossible to exactly describe what goes wrong. But before calling that deployments is a list containing a single element that is a dict (with keys apiVersion, kind, etc.). And after that call deployments is a list of single elements list (which elements is aformentioned dict). You iterate over the "outer" list and dump a single element list, which, in block style, gives you the - which is the block sequence element indicator.

If you can't fix define_exp_parameters() to return a list for which each element is a dict again, you can just dump the first element of deployment:

testyaml.dump(deployment[0], created_file)

Upvotes: 1

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