使用参数访问 JQ 变量

Question

我正在尝试根据此 JSON 的键获取值：

{
  "streams": {
    "vs-first": {
      "version": "2.33.0",
      "branch": "ewewew",
      "hash": "ewewewewe",
      "widgets": []
    },
    "vs-second": {
      "version": "1.58.0",
      "branch": "ewewew",
      "hash": "ewewew",
      "widgets": []
    },
    "vs-third": {
      "version": "1.42.0",
      "branch": "ewewew",
      "hash": "ewewe",
      "widgets": []
    },
    "vs-fourth": {
      "version": "1.58.0",
      "branch": "eewfwfef",
      "hash": "vvfffsfsf",
      "widgets": []
    },
    "vs-fifth": {
      "version": "1.39.0",
      "branch": "fvrvvsdvds",
      "hash": "vvsvdsvds",
      "widgets": [
        "1",
        "2",
        "3",
        "4"
      ]
    }
  }
}

这是我的脚本实现：

jq -r '.streams|keys[]' $vsconfig | while read key ; do
    if [ $key == "[" ] || [ $key == "]" ]; then
      continue
    fi

    if [ $key == "vs-first" ]; then
      version=$(jq -r '.streams.vs-first.version' $vsconfig)
      branch=$(jq -r '.streams.vs-first.branch' $vsconfig)
      hash=$(jq -r '.streams.vs-first.hash' $vsconfig)

      filename="one_file-$version-$branch-$hash.zip"
      createdUrl="$someurl/$version/$filename"

      curl $createdUrl --output ./som/random/dir --create-dirs
      ...
    else
      version=$(jq -r --arg v keyvar $key 'streams.[$keyvar].branch' $vsconfig)
      branch=`jq --arg keyvar "streams.$key.branch" '$keyvar' $vsconfig`
      hash=`jq --arg keyvar "streams.$key.hash" '$keyvar' $vsconfig`

      filename = "$key-$version"
      if [ $branch == "some_branch" ]; then
        filename="one_file-$version-$branch-$hash.zip"
      else
        filename="$filename.zip"
      fi

      curl $createdUrl --output ./som/random/dir --create-dirs
    fi

    echo "Version: $version Branch: $branch Hash: $hash"
done

我尝试了多种格式，即：

version=$(jq -r --arg v keyvar $key 'streams.[$keyvar].branch' $vsconfig)

还有：

branch=`jq --arg keyvar "streams.$key.branch" '$keyvar' $vsconfig`

它给出了这个错误：

jq: error: support/0 is not defined at <top-level>, line 1:

Answer 1

jq 相当复杂。最好的选择可能是在单个 jq 调用中完成所有这些操作，并且使用最少的或没有 bash 脚本。

仅值

首先，您可以通过将[] 应用于.streams 对象来获取每个版本/分支/哈希对象。在对象或键/值映射上使用 [] 会提取值并丢弃键。

$ jq -c '.streams[]' vs.json
{"version":"2.33.0","branch":"ewewew","hash":"ewewewewe","widgets":[]}
{"version":"1.58.0","branch":"ewewew","hash":"ewewew","widgets":[]}
{"version":"1.42.0","branch":"ewewew","hash":"ewewe","widgets":[]}
{"version":"1.58.0","branch":"eewfwfef","hash":"vvfffsfsf","widgets":[]}
{"version":"1.39.0","branch":"fvrvvsdvds","hash":"vvsvdsvds","widgets":[]}

然后，您可以通过将上述对象传递到一个过滤器来获取您感兴趣的各个字段，该过滤器抓取 .version、.branch 和 .hash 并将三个值放入一个数组中：

$ jq -c '.streams[] | [.version, .branch, .hash]' vs.json
["2.33.0","ewewew","ewewewewe"]
["1.58.0","ewewew","ewewew"]
["1.42.0","ewewew","ewewe"]
["1.58.0","eewfwfef","vvfffsfsf"]
["1.39.0","fvrvvsdvds","vvsvdsvds"]

要让它格式化结果，您可以生成字符串而不是列表，并使用\(...) 嵌入值。 -r 标志告诉它打印原始结果：换句话说，打印不带引号的字符串。

$ jq -r '.streams[] | "Version: \(.version) Branch: \(.branch) Hash: \(.hash)"' vs.json
Version: 2.33.0 Branch: ewewew Hash: ewewewewe
Version: 1.58.0 Branch: ewewew Hash: ewewew
Version: 1.42.0 Branch: ewewew Hash: ewewe
Version: 1.58.0 Branch: eewfwfef Hash: vvfffsfsf
Version: 1.39.0 Branch: fvrvvsdvds Hash: vvsvdsvds

键和值

要将键添加到组合中，您可以使用to_entries，它从对象中提取键/值对：

$ jq -c '.streams | to_entries[]' vs.json
{"key":"vs-first","value":{"version":"2.33.0","branch":"ewewew","hash":"ewewewewe","widgets":[]}}
{"key":"vs-second","value":{"version":"1.58.0","branch":"ewewew","hash":"ewewew","widgets":[]}}
{"key":"vs-third","value":{"version":"1.42.0","branch":"ewewew","hash":"ewewe","widgets":[]}}
{"key":"vs-fourth","value":{"version":"1.58.0","branch":"eewfwfef","hash":"vvfffsfsf","widgets":[]}}
{"key":"vs-fifth","value":{"version":"1.39.0","branch":"fvrvvsdvds","hash":"vvsvdsvds","widgets":[]}}

抽出不同的字段就变成了：

$ jq -c '.streams | to_entries[] | [.key, .value.version, .value.branch, .value.hash]' vs.json
["vs-first","2.33.0","ewewew","ewewewewe"]
["vs-second","1.58.0","ewewew","ewewew"]
["vs-third","1.42.0","ewewew","ewewe"]
["vs-fourth","1.58.0","eewfwfef","vvfffsfsf"]
["vs-fifth","1.39.0","fvrvvsdvds","vvsvdsvds"]

或者等效地，重构出重复的.value 查找：

jq -c '.streams | to_entries[] | [.key, (.value | .version, .branch, .hash)]' vs.json
["vs-first","2.33.0","ewewew","ewewewewe"]
["vs-second","1.58.0","ewewew","ewewew"]
["vs-third","1.42.0","ewewew","ewewe"]
["vs-fourth","1.58.0","eewfwfef","vvfffsfsf"]
["vs-fifth","1.39.0","fvrvvsdvds","vvsvdsvds"]

添加 bash 处理

jq 不能做所有事情，所以如果你确实想将结果输出到 bash 以进行额外的处理——例如，调用 curl——你可以使用 -r 在单独的行上打印每个值并使用 @987654338 @ 将行读入变量。它看起来像这样：

jq -r '.streams | to_entries[] | .key, (.value | .version, .branch, .hash)' vs.json |
    while read -r key &&
          read -r version &&
          read -r branch &&
          read -r hash
    do
        ...
    done