I'm pasting here a JSON example data which would require some manipulation to get a desired output which is mentioned in the next section to be read after this piece of JSON code.
I want to use jq for parsing my desired data.
{
"MetricAlarms": [
{
"EvaluationPeriods": 3,
"ComparisonOperator": "GreaterThanOrEqualToThreshold",
"AlarmActions": [
"Unimportant:Random:alarm:ELK2[10.1.1.2]-Root-Disk-Alert"
],
"AlarmName": "Unimportant:Random:alarm:ELK1[10.1.1.0]-Root-Alert",
"Dimensions": [
{
"Name": "path",
"Value": "/"
},
{
"Name": "InstanceType",
"Value": "m5.2xlarge"
},
{
"Name": "fstype",
"Value": "ext4"
}
],
"DatapointsToAlarm": 3,
"MetricName": "disk_used_percent"
},
{
"EvaluationPeriods": 3,
"ComparisonOperator": "GreaterThanOrEqualToThreshold",
"AlarmActions": [
"Unimportant:Random:alarm:ELK2[10.1.1.2]"
],
"AlarmName": "Unimportant:Random:alarm:ELK2[10.1.1.2]",
"Dimensions": [
{
"Name": "path",
"Value": "/"
},
{
"Name": "InstanceType",
"Value": "r5.2xlarge"
},
{
"Name": "fstype",
"Value": "ext4"
}
],
"DatapointsToAlarm": 3,
"MetricName": "disk_used_percent"
}
]
}
So when I Pass some Key1 & value1 as a parameter "Name": "InstanceType", to the JQ probably using cat | jq and output expected should be as below
m5.2xlarge
r5.2xlarge
A generic approach to search for a key-value pair (sk-sv) in input recursively and extract another key's value (pv) from objects found:
jq -r --arg sk Name \
--arg sv InstanceType \
--arg pv Value \
'.. | objects | select(contains({($sk): $sv})) | .[$pv]' file
Related
I have two JSON files a.json and b.json. The contents in a.json file is a JSON object and inside b.json its an array.I want to add/update status field in each mappings in a.json by retrieving the value from b.json file.
a.json:
{
"title": 25886,
"data": {
"request": {
"c": 46369,
"t1": 1562050127.376641
},
},
"rs": {
"mappings": {
"12345": {
"id": "12345",
"name": "test",
"customer_id": "11228",
},
"45678": {
"id": "45678",
"name": "abc",
"customer_id": "11206",
}
}
}}
b.json:
[
{
"status": "pending",
"extra": {
"name": "test"
},
"enabled": true,
"id": "12345"
},
{
"status": "not_started",
"extra": {
"name": "abc"
},
"enabled": true,
"id": "45678"
}
]
Below is my expected output:
{
"title": 25886,
"data": {
"request": {
"c": 46369,
"t1": 1562050127.376641
},
},
"rs": {
"mappings": {
"12345": {
"id": "12345",
"name": "test",
"customer_id": "11228",
"status":"pending"
},
"45678": {
"id": "45678",
"name": "abc",
"customer_id": "11206",
"status":"not_started"
}
}
}}
In this expected JSON file we have status field whose value is retrieved from b.json file based on a matching id value. How to do this using jq ?
For the purposes of this problem, b.json essentially defines a dictionary, so for simplicity, efficiency and perhaps elegance,
it make sense to start by using the builtin function INDEX to create the relevant dictionary:
INDEX( $b[] | {id, status}; .id )
This assumes an invocation of jq along the lines of:
jq --argfile b b.json -f update.jq a.json
(Yes, I know --argfile has been deprecated. Feel free to choose another way to set $b to the contents of b.json.)
Now, to perform the update, it will be simplest to use the "update" operator, |=, in conjunction with map_values. (Feel free to check the jq manual :-)
Putting everything together:
INDEX( $b[] | {id, status}; .id ) as $dict
| .rs.mappings |= map_values( .status = $dict[.id].status )
Let's say I have the following JSON output:
{
"Stacks": [
{
"StackName": "hello-world",
"Tags": [
{
"Key": "environment",
"Value": "sandbox"
},
{
"Key": "Joe Shmo",
"Value": "Dev"
}
]
},
{
"StackName": "hello-man",
"Tags": [
{
"Key": "environment",
"Value": "live"
},
{
"Key": "Tandy",
"Value": "Dev"
}
]
}
]
}
How would I write a jq query to grab all StackNames for stacks that do NOT have a Tags value "Key": "Joe Shmo"? So the result would return simply hello-man.
.Stacks[]
| select( any(.Tags[]; .Key == "Joe Shmo" ) | not)
| .StackName
This checks for equality efficiently (any has short-circuit semantics), whereas contains would check for containment.
Using contains, like this:
jq -r '.Stacks[]|select(.Tags|contains([{"Key": "Joe Shmo"}])|not).StackName'
Note: -r removes the quotes from output, otherwise jq would print "hello-man" (within double quotes)
I have two questions:
How can I use jq to search for "name" fields that start with an underscore (like _RDS_PASSWORD) and remove the leading underscore (so it becomes RDS_PASSWORD)
How can I use jq for "name" fields that start with an underscore (like _RDS_PASSWORD) and pass the value of the value cGFzc3dvcmQK to be decoded via base64? (ex: "cGFzc3dvcmQK" | base64 --decode)
Input:
[
{
"name": "RDS_DB_NAME",
"value": "rds_db_name"
},
{
"name": "RDS_HOSTNAME",
"value": "rds_hostname"
},
{
"name": "RDS_PORT",
"value": "1234"
},
{
"name": "RDS_USERNAME",
"value": "rds_username"
},
{
"name": "_RDS_PASSWORD",
"value": "cGFzc3dvcmQK"
}
]
Desired output:
[
{
"name": "RDS_DB_NAME",
"value": "rds_db_name"
},
{
"name": "RDS_HOSTNAME",
"value": "rds_hostname"
},
{
"name": "RDS_PORT",
"value": "1234"
},
{
"name": "RDS_USERNAME",
"value": "rds_username"
},
{
"name": "RDS_PASSWORD",
"value": "password"
}
]
Q1
walk( if type=="object" and has("name") and .name[0:1] == "_"
then .name |= .[1:]
else .
end)
If your jq does not have walk/1 then you can either upgrade to a more recent version of jq than 1.5, or include its def, which can be found at https://github.com/stedolan/jq/blob/master/src/builtin.jq
Q2
.. | objects | select(has("name") and .name[0:1] == "_") | .value
If you are certain that the encoded string was a UTF-8 string, you could use jq's #base64d; otherwise, invoke jq with the -r option and pipe the results to a decoder as you indicated you planned to do.
I have a JSON document that looks like the following. Note this is a simplified example of the real JSON, which is included at bottom of question:
{
"some_array": [
{
"k1": "A",
"k2": "XXX"
},
{
"k1": "B",
"k2": "YYY"
}
]
}
I would like to change the value of all the k2 keys in the some_array array where the value of the k1 key is "B".
Is this possible using jq ?
For reference this is the actual JSON document, which is an environment variable file for use in postman / newman tool. I am attempting this conversion using JQ because the tool does not yet support command line overrides of specific environment variables
Actual JSON
{
"name": "Local-Stack-Env-Config",
"values": [
{
"enabled": true,
"key": "KC_master_host",
"type": "text",
"value": "http://localhost:8087"
},
{
"enabled": true,
"key": "KC_user_guid",
"type": "text",
"value": "11111111-1111-1111-1111-11111111111"
}
],
"timestamp": 1502768145037,
"_postman_variable_scope": "environment",
"_postman_exported_at": "2017-08-15T03:36:41.474Z",
"_postman_exported_using": "Postman/5.1.3"
}
Here is a slightly simpler version of zayquan's filter:
.some_array |= map(if .k1=="B" then .k2="changed" else . end)
Here's another solution.
jq '(.some_array[] | select(.k1 == "B") | .k2) |= "new_value"'
Output
{
"some_array": [
{
"k1": "A",
"k2": "XXX"
},
{
"k1": "B",
"k2": "new_value"
}
]
}
Here is a viable solution:
cat some.json | jq '.some_array = (.some_array | map(if .k1 == "B" then . + {"k2":"changed"} else . end))'
produces the output:
"some_array": [
{
"k1": "A",
"k2": "XXX"
},
{
"k1": "B",
"k2": "changed"
}
]
}
jq strikes again. Trying to get the value of DATABASES_DEFAULT based on the name in a json file that has a whole lot of names and I'm completely lost.
My file looks like the following (output of an aws ecs describe-task-definition) only much more complex; I've stripped this to the most basic example I can where the structure is still intact.
{
"taskDefinition": {
"status": "bar",
"family": "bar2",
"volumes": [],
"taskDefinitionArn": "bar3",
"containerDefinitions": [
{
"dnsSearchDomains": [],
"environment": [
{
"name": "bar4",
"value": "bar5"
},
{
"name": "bar6",
"value": "bar7"
},
{
"name": "DATABASES_DEFAULT",
"value": "foo"
}
],
"name": "baz",
"links": []
},
{
"dnsSearchDomains": [],
"environment": [
{
"name": "bar4",
"value": "bar5"
},
{
"name": "bar6",
"value": "bar7"
},
{
"name": "DATABASES_DEFAULT",
"value": "foo2"
}
],
"name": "boo",
"links": []
}
],
"revision": 1
}
}
I need the value of DATABASES_DEFAULT where the name is baz. Note that there are a lot of keypairs with name, I'm specifically talking about the one outside of environment.
I've been tinkering with this but only got this far before realizing that I don't understand how to access nested values.
jq '.[] | select(.name==DATABASES_DEFAULT) | .value'
which is returning
jq: error: DATABASES_DEFAULT/0 is not defined at <top-level>, line 1:
.[] | select(.name==DATABASES_DEFAULT) | .value
jq: 1 compile error
Obviously this a) doesn't work, and b) even if it did, it's independant of the name value. My thought was to return all the db defaults and then identify the one with baz, but I don't know if that's the right approach.
I like to think of it as digging down into the structure, so first you open the outer layers:
.taskDefinition.containerDefinitions[]
Now select the one you want:
select(.name =="baz")
Open the inner structure:
.environment[]
Select the desired object:
select(.name == "DATABASES_DEFAULT")
Choose the key you want:
.value
Taken together:
parse.jq
.taskDefinition.containerDefinitions[] |
select(.name =="baz") |
.environment[] |
select(.name == "DATABASES_DEFAULT") |
.value
Run it like this:
<infile jq -f parse.jq
Output:
"foo"
The following seems to work:
.taskDefinition.containerDefinitions[] |
select(
select(
.environment[] | .name == "DATABASES_DEFAULT"
).name == "baz"
)
The output is the object with the name key mapped to "baz".
$ jq '.taskDefinition.containerDefinitions[] | select(select(.environment[]|.name == "DATABASES_DEFAULT").name=="baz")' tmp.json
{
"dnsSearchDomains": [],
"environment": [
{
"name": "bar4",
"value": "bar5"
},
{
"name": "bar6",
"value": "bar7"
},
{
"name": "DATABASES_DEFAULT",
"value": "foo"
}
],
"name": "baz",
"links": []
}