使用python迭代和更新json值

Question

我有以下 json：

{
  "taskDefinition": {
    "containerDefinitions": [
      {
        "memoryReservation": 1040,
        "mountPoints": [

        ],
        "name": "staging-web1",
        "image": "1234567.dkr.ecr.us-west-2.amazonaws.com\/staging:staging-web",
        "essential": true,
        "environment": [
          {
            "name": "REVISION",
            "value": ""
          },
          {
            "name": "RELEASE_VERSION",
            "value": ""
          },
          {
            "name": "ENVIRONMENT",
            "value": ""
          }
        ],
        "logConfiguration": {
          "logDriver": "awslogs",
          "options": {
            "awslogs-region": "us-west-2",
            "awslogs-group": "\/ecs\/staging",
            "awslogs-stream-prefix": "ecs"
          }
        },
        "portMappings": [

        ],
        "cpu": 0,
        "volumesFrom": [

        ]
      },
      {
        "memoryReservation": 1040,
        "mountPoints": [

        ],
        "name": "s-staging-nosql1",
        "image": "1234567.dkr.ecr.us-west-2.amazonaws.com\/staging:staging-nosql",
        "essential": true,
        "environment": [
          {
            "name": "REVISION",
            "value": ""
          },
          {
            "name": "RELEASE_VERSION",
            "value": ""
          },
          {
            "name": "ENVIRONMENT",
            "value": ""
          }  
        ],
        "logConfiguration": {
          "logDriver": "awslogs",
          "options": {
            "awslogs-region": "us-west-2",
            "awslogs-group": "\/ecs\/staging",
            "awslogs-stream-prefix": "ecs"
          }
        },
        "portMappings": [

        ],
        "cpu": 0,
        "volumesFrom": [

        ]
      },
      {
        "memoryReservation": 1040,
        "mountPoints": [

        ],
        "name": "s-staging-db1",
        "image": "1234567.dkr.ecr.us-west-2.amazonaws.com\/staging:staging-db",
        "essential": true,
        "environment": [
          {
            "name": "REVISION",
            "value": ""
          },
          {
            "name": "RELEASE_VERSION",
            "value": ""
          },
          {
            "name": "ENVIRONMENT",
            "value": ""
          }  
        ],
        "logConfiguration": {
          "logDriver": "awslogs",
          "options": {
            "awslogs-region": "us-west-2",
            "awslogs-group": "\/ecs\/staging",
            "awslogs-stream-prefix": "ecs"
          }
        },
        "portMappings": [

        ],
        "cpu": 0,
        "volumesFrom": [

        ]
      }
    ]
  }
}

我尝试用python做的是在containerDefinitions中调整每个环境下的REVISION、RELEASE_VERSION和ENVIRONMENT。

在python方面我是个新手，但我正在尝试如下：

NEW_CONTAINER_DEF=$(echo "${PREVIOUS_TASK_DEF}" | python <(cat <<-EOF
import sys, json
json_data = json.load(sys.stdin)
for item in json_data['taskDefinition']['containerDefinitions']:
    if json_data.get(['environment']['name'])  == "REVISION":
         item['environment']['value']  = "myrevision"
print json.dumps(json_data)
EOF
))

不用说上面的代码不起作用。有更多 python 经验的人可以帮助我了解如何迭代和更新值吗？

谢谢！

Answer 1

请注意，调用json.load 只是将the json 序列化为python dictionary。您可以相应地修改该字典。

看来首先您想遍历所有taskDefinition.containerDefinitions，然后您想遍历这些定义中的所有environments，并设置环境value，如果环境name是REVISION .看到这个：

for item in json_data["taskDefinition"]["containerDefinitions"]:
    for env in item["environment"]:
         if env["name"] == "REVISION":
             env["value"] = "myrevision"
print json.dumps(json_data, indent=4)