如何简化命令行的aws DynamoDB查询JSON输出？
如何简化命令行的aws DynamoDB查询JSON输出？
提问于 2015-02-18 20:39:59
我和面向DynamoDB的AWS命令行接口一起工作。
当我们查询一个条目时，我们会得到一个非常详细的JSON输出。您可以得到类似的内容(它是从get-item构建的，以便几乎是详尽的( NULL类型已被省略) aws命令行帮助
{
"Count": 1,
"Items": [
{
"Id": {
"S": "app1"
},
"Parameters": {
"M": {
"nfs": {
"M": {
"IP" : {
"S" : "172.16.0.178"
},
"defaultPath": {
"S": "/mnt/ebs/"
},
"key": {
"B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"
},
"activated": {
"BOOL": true
}
}
},
"ws" : {
"M" : {
"number" : {
"N" : "5"
},
"values" : {
"L" : [
{ "S" : "12253456346346"},
{ "S" : "23452353463464"},
{ "S" : "23523453461232"},
{ "S" : "34645745675675"},
{ "S" : "46456745757575"}
]
}
}
}
}
},
"Oldtypes": {
"typeSS" : {"SS" : ["foo", "bar", "baz"]},
"typeNS" : {"NS" : ["0", "1", "2", "3", "4", "5"]},
"typeBS" : {"BS" : ["VGVybWluYXRvcgo=", "VGVybWluYXRvciAyOiBKdWRnbWVudCBEYXkK", "VGVybWluYXRvciAzOiBSaXNlIG9mIHRoZSBNYWNoaW5lcwo=", "VGVybWluYXRvciA0OiBTYWx2YXRpb24K","VGVybWluYXRvciA1OiBHZW5lc2lzCg=="]}
}
}
],
"ScannedCount": 1,
"ConsumedCapacity": null
}有什么方法可以为Items部件获得更简单的输出吗？如下所示：
{
"ConsumedCapacity": null,
"Count": 1,
"Items": [
{
"Id": "app1",
"Parameters": {
"nfs": {
"IP": "172.16.0.178",
"activated": true,
"defaultPath": "/mnt/ebs/",
"key": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"
},
"ws": {
"number": 5,
"values": ["12253456346346","23452353463464","23523453461232","34645745675675","46456745757575"]
}
},
"Oldtypes": {
"typeBS": ["VGVybWluYXRvcgo=", "VGVybWluYXRvciAyOiBKdWRnbWVudCBEYXkK", "VGVybWluYXRvciAzOiBSaXNlIG9mIHRoZSBNYWNoaW5lcwo=", "VGVybWluYXRvciA0OiBTYWx2YXRpb24K", "VGVybWluYXRvciA1OiBHZW5lc2lzCg=="],
"typeNS": [0, 1, 2, 3, 4, 5],
"typeSS": ["foo","bar","baz"]
}
}
],
"ScannedCount": 1
}在dynamodb - AWS CLI 1.7.10文档中没有任何帮助。
我们必须从命令行得到结果。如果有必要，我愿意使用其他命令行工具，如jq，但这样的jq映射对我来说似乎很复杂。
jq更新1:基于的解决方案(借助DanielH的回答)
使用jq很容易，但并不是很漂亮，您可以这样做：
$> aws dynamodb query --table-name ConfigCatalog --key-conditions '{ "Id" : {"AttributeValueList": [{"S":"app1"}], "ComparisonOperator": "EQ"}}' | jq -r '.Items[0].Parameters.M."nfs#IP".S'结果是：172.16.0.178
jq -r选项为您提供了一个原始输出。
jq 2:基于的解决方案(在@jeff的帮助下)
下面是Jeff jq函数的更新和注释版本，以取消DynamoDB输出。它将为您提供预期的输出：
$> cat unmarshal_dynamodb.jq
def unmarshal_dynamodb:
# DynamoDB string type
(objects | .S)
# DynamoDB blob type
// (objects | .B)
# DynamoDB number type
// (objects | .N | strings | tonumber)
# DynamoDB boolean type
// (objects | .BOOL)
# DynamoDB map type, recursion on each item
// (objects | .M | objects | with_entries(.value |= unmarshal_dynamodb))
# DynamoDB list type, recursion on each item
// (objects | .L | arrays | map(unmarshal_dynamodb))
# DynamoDB typed list type SS, string set
// (objects | .SS | arrays | map(unmarshal_dynamodb))
# DynamoDB typed list type NS, number set
// (objects | .NS | arrays | map(tonumber))
# DynamoDB typed list type BS, blob set
// (objects | .BS | arrays | map(unmarshal_dynamodb))
# managing others DynamoDB output entries: "Count", "Items", "ScannedCount" and "ConsumedCapcity"
// (objects | with_entries(.value |= unmarshal_dynamodb))
// (arrays | map(unmarshal_dynamodb))
# leaves values
// .
;
unmarshal_dynamodb如果将DynamoDB查询输出保存到文件中，例如ddb-query-result.json，则可以执行以获得所需的结果：
$> jq -f unmarshal_dynamodb.jq ddb-query-result.json回答 6
Stack Overflow用户
回答已采纳
发布于 2015-02-21 03:05:59
您可以使用精心编制的函数递归地解码这些值。看起来键名对应于一种类型：
S -> string
N -> number
M -> map如果可能的话，处理您想要解码的每一种情况，否则过滤掉它。您可以使用各种类型滤波器和替代算子来这样做。
$ cat input.json
{
"Count": 1,
"Items": [
{
"Id": { "S": "app1" },
"Parameters": {
"M": {
"nfs#IP": { "S": "192.17.0.13" },
"maxCount": { "N": "1" },
"nfs#defaultPath": { "S": "/mnt/ebs/" }
}
}
}
],
"ScannedCount": 1,
"ConsumedCapacity": null
}$ cat ~/.jq
def decode_ddb:
def _sprop($key): select(keys == [$key])[$key]; # single property objects only
((objects | { value: _sprop("S") }) # string (from string)
// (objects | { value: _sprop("B") }) # blob (from string)
// (objects | { value: _sprop("N") | tonumber }) # number (from string)
// (objects | { value: _sprop("BOOL") }) # boolean (from boolean)
// (objects | { value: _sprop("M") | map_values(decode_ddb) }) # map (from object)
// (objects | { value: _sprop("L") | map(decode_ddb) }) # list (from encoded array)
// (objects | { value: _sprop("SS") }) # string set (from string array)
// (objects | { value: _sprop("NS") | map(tonumber) }) # number set (from string array)
// (objects | { value: _sprop("BS") }) # blob set (from string array)
// (objects | { value: map_values(decode_ddb) }) # all other non-conforming objects
// (arrays | { value: map(decode_ddb) }) # all other non-conforming arrays
// { value: . }).value # everything else
;$ jq 'decode_ddb' input.json
{
"Count": 1,
"Items": [
{
"Id": "app1",
"Parameters": {
"nfs#IP": "192.17.0.13",
"maxCount": 1,
"nfs#defaultPath": "/mnt/ebs/"
}
}
],
"ScannedCount": 1,
"ConsumedCapacity": null
}Stack Overflow用户
发布于 2015-02-23 19:46:28
实现post目标的另一种方法是使用node.js扩展，如node-dynamodb或dynamodb-marshaler，并构建node命令行工具。
使用node.js：创建第一个Node.js命令行应用程序构建套餐：创建第一个Node.js命令行应用程序命令行应用程序的有趣教程
这里有一个快速而肮脏的单线器，它从stdin中读取一条记录并以简化的形式打印出来：
node -e 'console.log(JSON.stringify(require("aws-sdk").DynamoDB.Converter.unmarshall(JSON.parse(require("fs").readFileSync(0, "utf-8")))))'Stack Overflow用户
发布于 2021-12-14 00:23:16
下面是可以处理空值的jq解决方案的更新版本。
$> cat unmarshal_dynamodb.jq
def unmarshal_dynamodb:
# null
walk( if type == "object" and .NULL then . |= null else . end ) |
# DynamoDB string type
(objects | .S)
# DynamoDB blob type
// (objects | .B)
# DynamoDB number type
// (objects | .N | strings | tonumber)
# DynamoDB boolean type
// (objects | .BOOL)
# DynamoDB map type, recursion on each item
// (objects | .M | objects | with_entries(.value |= unmarshal_dynamodb))
# DynamoDB list type, recursion on each item
// (objects | .L | arrays | map(unmarshal_dynamodb))
# DynamoDB typed list type SS, string set
// (objects | .SS | arrays | map(unmarshal_dynamodb))
# DynamoDB typed list type NS, number set
// (objects | .NS | arrays | map(tonumber))
# DynamoDB typed list type BS, blob set
// (objects | .BS | arrays | map(unmarshal_dynamodb))
# managing others DynamoDB output entries: "Count", "Items", "ScannedCount" and "ConsumedCapcity"
// (objects | with_entries(.value |= unmarshal_dynamodb))
// (arrays | map(unmarshal_dynamodb))
# leaves values
// .
;
unmarshal_dynamodb$> jq -f unmarshal_dynamodb.jq ddb-query-result.json请归功于“”和“herve”的原始版本。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/28593471
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