如何用Python为YAML文件添加缩进文本并替换探针配置

我有一个YAML文件，想要从另一个YAML文件导入参数，添加并替换其中缺失的参数，但生成的最终文件出了问题：livenessProbe配置没有在正确的缩进位置，反而跑到了文件末尾。需要把该配置替换到对应位置并保持正确的缩进格式。

有问题的YAML文件 #

---
apiVersion: apps/v1
kind: Deployment
metadata:
    name: ms
spec:
    template:
        metadata:
            annotations:
                cluster-autoscaler.kubernetes.io/safe-to-evict: 'true'
        spec:
            containers:
               -  name: ms
                  command: [npm, run, start:prod]
                  resources:
                      requests:
                          memory: 256Mi
                          cpu: 150m
                      limits:
                          memory: 512Mi
                          cpu: 150m
                  readinessProbe:
                  livenessProbe:
livenessProbe:
    failureThreshold: 3
    httpGet:
        path: /LIVENESS
        port: PORT
        scheme: HTTP
    initialDelaySeconds: 30
    periodSeconds: 2
    successThreshold: 1
    timeoutSeconds: 1

当前使用的Python代码 #

from posixpath import abspath
from ruamel.yaml import YAML
import yaml
import os
import sys

pathroot = os.getcwd()

os.system('clear')

text = "requests:"
notext = "failureThreshold:"

with open('template-live.yaml', 'r') as file:
    resourceslistlive = yaml.load(file, Loader=yaml.FullLoader)

with open('template-ready.yaml', 'r') as file:
    resourceslistready = yaml.load(file, Loader=yaml.FullLoader)

def searchText(path):

    findString = False

    with open(path, 'r', encoding='utf-8') as f:
        content = f.read()
        if text in content:
            findString = True

        if notext in content:
            findString = False
        f.close()
    if findString:
        with open(path, 'a') as fileA:
            yaml.dump(resourceslistlive, fileA)

        with open(path, 'a') as fileB:
            yaml.dump(resourceslistready, fileB)

name = "patch-resources-limit.yaml"
archivos = 0

for root, dirs, files in os.walk(pathroot):
    if name in files:
        searchText(os.path.join(root, name))

你的代码问题在于直接用yaml.dump()把内容追加到文件末尾，没有定位到YAML结构中containers下的对应位置，导致配置被放到了根层级，而非容器的子节点里。另外，你导入了ruamel.yaml却没用到，它比标准库yaml更适合处理YAML的结构和缩进保留。

修复步骤 #

• 用ruamel.yaml处理YAML结构，保留原文件的缩进和注释，精准修改指定节点
• 定位到spec.template.spec.containers下的目标容器，替换其中的readinessProbe和livenessProbe
• 不再直接追加文件，而是加载原YAML的结构，修改后再写回文件

修改后的代码 #

import os
import ruamel.yaml

pathroot = os.getcwd()
os.system('clear')

# 加载探针配置
with open('template-live.yaml', 'r') as file:
    yaml = ruamel.yaml.YAML()
    liveness_probe = yaml.load(file)

with open('template-ready.yaml', 'r') as file:
    readiness_probe = yaml.load(file)

def update_yaml(path):
    # 加载目标YAML文件
    yaml = ruamel.yaml.YAML()
    with open(path, 'r', encoding='utf-8') as f:
        doc = yaml.load(f)
    
    # 检查是否存在目标结构
    if not doc or 'spec' not in doc or 'template' not in doc['spec']:
        return
    
    containers = doc['spec']['template']['spec'].get('containers', [])
    if not containers:
        return
    
    # 找到名为ms的容器，替换探针配置
    for container in containers:
        if container.get('name') == 'ms':
            container['livenessProbe'] = liveness_probe
            container['readinessProbe'] = readiness_probe
            break
    
    # 写回修改后的内容
    with open(path, 'w', encoding='utf-8') as f:
        yaml.dump(doc, f)

target_file = "patch-resources-limit.yaml"
for root, dirs, files in os.walk(pathroot):
    if target_file in files:
        update_yaml(os.path.join(root, target_file))

说明 #

• 使用ruamel.yaml加载和保存YAML，完美保留原文件的缩进格式
• 直接定位到containers下的ms容器，将探针配置赋值到对应节点，确保缩进正确
• 不再通过字符串匹配判断，而是直接检查YAML结构是否符合预期，逻辑更可靠

内容的提问来源于stack exchange，提问作者Luis A Delgado Lisińska