使用 sed 或 jq 删除动态生成的 JSON 数组中的最后一个 `},`

Question

我正在尝试动态生成 JSON，但是，我遵循的方法留下了最后一个 },，使 JSON 无效：

#Initializing Current State file
    echo "[" > state.json
    # Getting list of all EKS clusters
    for cluster in $(aws eks list-clusters --output text | awk '{print }')
    do
      echo "====== $cluster ======"
      # Get list of all ASG from cluster
      for asg in $(aws autoscaling describe-auto-scaling-groups  --query 'AutoScalingGroups[?contains(Tags[?Key==`eks:cluster-name`].Value, `'"$cluster"'`)].[AutoScalingGroupName]' --output text)
      do
        echo "Getting capacity for ASG: $asg"
        MinSize=$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-name $asg --query 'AutoScalingGroups[*].MinSize' --output text)
        DesiredCapacity=$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-name $asg --query 'AutoScalingGroups[*].DesiredCapacity' --output text)  
        MaxSize=$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-name $asg --query 'AutoScalingGroups[*].MaxSize' --output text)
        JSON_STRING=$( jq -n \
                  --arg cn "$cluster" \
                  --arg asg "$asg" \
                  --arg MinSize "$MinSize" \
                  --arg DesiredCapacity "$DesiredCapacity" \
                  --arg MaxSize "$MaxSize" \
                  '{cluster: $cn, asgname: $asg, minSize: $MinSize, DesiredCapacity: $DesiredCapacity, MaxSize: $MaxSize}' )
        echo "${JSON_STRING}," >> state.json
      done
    done
    #Finalizing Current State file
    echo "]" >> state.json

$ cat state.json
[
{
  "cluster": "eks-b",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
},
{
  "cluster": "eks-b",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
},
{
  "cluster": "dev",
  "asgname": "eks-12345",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
},
{
  "cluster": "dev",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
},
{
  "cluster": "eks-a",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
},
{
  "cluster": "eks-a",
  "asgname": "eks-1323",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
},
]

jq 验证：

$ cat state.json  | jq empty
parse error: Expected another array element at line 44, column 1

我尝试了多种选择，主要是 sed，但没有满足仅删除最后一次出现的 }, 的特定要求任何建议表示赞赏。

Answer 1

通过不打印括号和逗号，让您的脚本只生成对象流。

echo "${JSON_STRING}" >> state.json

state.json 应该包含一个对象流：

{
  "cluster": "eks-b",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
}
{
  "cluster": "eks-b",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
}
{
  "cluster": "dev",
  "asgname": "eks-12345",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
}
{
  "cluster": "dev",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
}
{
  "cluster": "eks-a",
  "asgname": "eks-1234",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
}
{
  "cluster": "eks-a",
  "asgname": "eks-1323",
  "minSize": "0",
  "DesiredCapacity": "0",
  "MaxSize": "0"
}

现在您可以使用 jq 读取该流，使用 -s 选项将其转换为适当的数组。

jq -s . state.json

[
  {
    "cluster": "eks-b",
    "asgname": "eks-1234",
    "minSize": "0",
    "DesiredCapacity": "0",
    "MaxSize": "0"
  },
  {
    "cluster": "eks-b",
    "asgname": "eks-1234",
    "minSize": "0",
    "DesiredCapacity": "0",
    "MaxSize": "0"
  },
  {
    "cluster": "dev",
    "asgname": "eks-12345",
    "minSize": "0",
    "DesiredCapacity": "0",
    "MaxSize": "0"
  },
  {
    "cluster": "dev",
    "asgname": "eks-1234",
    "minSize": "0",
    "DesiredCapacity": "0",
    "MaxSize": "0"
  },
  {
    "cluster": "eks-a",
    "asgname": "eks-1234",
    "minSize": "0",
    "DesiredCapacity": "0",
    "MaxSize": "0"
  },
  {
    "cluster": "eks-a",
    "asgname": "eks-1323",
    "minSize": "0",
    "DesiredCapacity": "0",
    "MaxSize": "0"
  }
]

Demo jq -s 部分

Answer 2

如果您不需要最终结果是 pretty-printed，您可以通过删除多余的逗号来节省调用 jq -s 的费用，例如

sed '$s/,$//'

或者如果您愿意：

sed -i.bak '$s/,$//'

更好的是，您可以避免在同一步骤中处理终止符“]”，例如使用 '$s/,$/]/'

使用 sed 或 jq 删除动态生成的 JSON 数组中的最后一个 `},`

Remove last `},` in a dynamically generated JSON array using sed or jq

bash

json

jq