通过Python和ruamel.yaml模块编辑YAML文件

Question

我需要编辑此yaml文件，以更改cpu和内存变量。我是一名初学者python开发人员。

我正在将python 3和ruamel.yaml用于sys模块。

要更改的Yaml：

- apiVersion: v1
  kind: ResourceQuota
  metadata:
    annotations:
      openshift.io/quota-tier: Medium
    creationTimestamp: 
    labels:
      quota-tier: Medium
    name: burst-quota
    namespace: testing
    resourceVersion: ""
    selfLink: /api/v1/namespaces/testing/resourcequotas/burst-quota
    uid: 
  spec:
    hard:
      cpu: "8"
      memory: 16Gi
  status:
    hard:
      cpu: "8"
      memory: 16Gi
    used:
      cpu: 20m
      memory: 256Mi

这是我的代码：

import sys
import ruamel.yaml

yaml = ruamel.yaml.YAML()

with open('quota-edit.yaml') as fp:
    data = yaml.load(fp)
for elem in data:
    if elem['kind'] == 'ResourceQuota':
         elem['spec'] = None
         elem['hard'] = None
         elem['cpu'] = 123  
         break     
yaml.dump(data, sys.stdout) 

我的代码输出是：

  -   apiVersion: v1
      kind: ResourceQuota
      metadata:
          annotations:
              openshift.io/quota-tier: Medium
          creationTimestamp: 
          labels:
              quota-tier: Medium
          name: burst-quota
          namespace: sre
          resourceVersion: ""
          selfLink: /api/v1/namespaces/testing/resourcequotas/burst-quota
          uid: 
      spec:
          hard:
              cpu: '8'
              memory: 16Gi
      status:
          hard:
              cpu: '8'
              memory: 16Gi
          used:
              cpu: 20m
              memory: 256Mi
      cpu: 123

我做错了什么？

谢谢，问候！

Answer 1

YAML是一个层次结构。当您阅读它时，将保留该层次结构。您的代码访问第二级元素（种类），并且可以按预期工作。但是要更改的元素位于更深的嵌套级别。您的代码尝试在错误的级别上对其进行修改。不要修改elem的子元素，但要一直沿层次进行下去：

import sys
import ruamel.yaml

yaml = ruamel.yaml.YAML()

with open('quota-edit.yaml') as fp:
    data = yaml.load(fp)
for elem in data:
    if elem['kind'] == 'ResourceQuota':
         elem['spec']['hard']['cpu'] = 123  
         break
yaml.dump(data, sys.stdout) 

这将替换spec.hard.cpu中的CPU项目。根据需要调整其他cpu条目。