I have this example test.json file:
{
"folder": {
"name": "Desktop",
"path": "Users/user/Desktop",
"executable": false
}
}
I am trying to read the object contained in 'folder' into a variable $var as an array. Desired output - $var contains the following:
[
{
"name": "Desktop",
"path": "Users/user/Desktop",
"executable": false
}
]
It seemed relatively straightforward. jq '.folder' test.json to read in the folder value, and then pipe the output using the -s flag to get it enclosed in an array. This command executes just fine:
jq '.folder' test.json | jq -s
However, when I try to save the result to a variable, it throws an error displaying the jq usage statement. What am I missing? Is there a different way to accomplish this?
var=$(jq '.folder' test.json | jq -s)
echo $var
I also found out that this works fine in zsh but throws an error in bash. Not sure if that's relevant and whether it has to do with different versions of jq
Is this what you were expecting ?
$ var="$(jq "[.folder]" test.json)"
$ echo "$var"
[
{
"name": "Desktop",
"path": "Users/user/Desktop",
"executable": false
}
]
Related
I don't understand what I'm doing wrong or why this does not work.
test.json file:
[
{
"Header": {
"Region": "US",
"Tenant": "Tenant1",
"Stage": "testing",
"ProductType": "old"
},
"Body": []
},
{
"Header": {
"Region": "EU",
"Tenant": "Tenant2",
"Stage": "development",
"ProductType": "new"
},
"Body": []
}
]
I want to display the values of the .Header.Tenant key. So the simple jq call does its job:
$ jq '[.[].Header.Tenant]' test.json
[
"Tenant1",
"Tenant2"
]
Now I want to assign that jq filter to a bash variable and use it with jq's --arg variable.
And I am getting this:
$ a=".[].Header.Tenant"; jq --arg xx "$a" '[$xx]' test.json
[
".[].Header.Tenant"
]
What is wrong?
jq does not have an eval function for evaluating arbitrary jq expressions, but it does provide functions that can be used to achieve much the same effect, the key idea being that certain JSON values can be used to specify query operations.
In your case, you would have to translate the jq query into a suitable jq operation, such as:
jq --argjson a '["Header","Tenant"]' '
getpath(paths|select( .[- ($a|length) :]== $a))
' test.json
Extending jq's JSON-based query language
More interestingly, you could write your own eval, e.g.
jq --argjson a '[[], "Header","Tenant"]' '
def eval($expr):
if $expr == [] then .
else $expr[0] as $op
| if $op == [] then .[] | eval($expr[1:])
else getpath([$op]) | eval($expr[1:])
end
end;
eval($a)
' test.json
With eval.jq as a module
If the above def of eval were put in a file, say ~/jq/eval.jq, then you could simply write:
jq -L ~/jq --argjson a '[[], "Header","Tenant"]' '
include "eval";
eval($a)' test.json
Or you could specify the search path in the jq program:
jq --argjson a '[[], "Header","Tenant"]' '
include "eval" { "search": "~/jq" };
eval($a)' input.json
Or you could use import ...
TLDR; The following code does the job:
$ a=".[].Header.Tenant"; jq -f <(echo "[$a]") test.json
[
"Tenant1",
"Tenant2"
]
One as well can add/modify the filter in the jq call, if needed:
$ a=".[].Header.Tenant"; jq -f <(echo "[$a]|length") test.json
2
Longer explanation
My ultimate goal was to figure out how I can define the lowest common denominator jq filter in a variable and use it when calling jq, plus add additional parameters if necessary. If you have a really complex jq filter spanning multiple lines that you call frequently, you probably want to template it somehow and use that template when calling jq.
While peak demonstrated how it can be done, I think it is overengineering the simple task.
However, using process substitution combined with the jq's -f option to read a filter from the file does solve my problem.
I have a json object with below element,
rsrecords="{
"ResourceRecords": [
{
"Value": "\"heritage=external-dns,external-dns/owner=us-east-1:sandbox,external-dns/resource=service/api""
}
],
"Type": "TXT",
"Name": "\\052.apiconsumer.alpha.sandbox.test.net.",
"TTL": 300
}"
And in my bash script,I have below code snippet,
jq -r '.[] | .Name ,.ResourceRecords[0].Value' <<< "$rsrecords" | \
while read -r name; read -r value; do
echo $name
Output is printed as,
\052.apiconsumer.alpha.sandbox.test.net.
But I am expecting it to print as \\052.apiconsumer.alpha.sandbox.test.net., which is , as it is "Name" from the json object..
How can this be done?
Before getting to the heart of the matter, please note that
the sample data as given is a bit of a mishmash, so I'll assume you meant something like:
rsrecords='
{
"ResourceRecords": [
{
"Value": "heritage=external-dns,external-dns/owner=us-east-1:sandbox,external-dns/resource=service/api"
}
],
"Type": "TXT",
"Name": "\\052.apiconsumer.alpha.sandbox.test.net.",
"TTL": 300
}
'
Your jq query does not match the above JSON, so I'll assume you intended the query to be simply:
.Name, .ResourceRecords[0].Value
In any case, with the above JSON, the bash commands:
jq -r '.Name, .ResourceRecords[0].Value' <<< "$rsrecords" |
while read -r name; read -r value; do
echo "$name"
done
yields:
\052.apiconsumer.alpha.sandbox.test.net.
This is correct, because the JSON string "\\X" is an encoding of the raw string: \X
If you want to see the JSON string, then invoke jq without the -r option. If you want to invoke jq with the -r option and want to see two backslashes, you will have to encode them as four backslashes in your JSON.
In the below script, I am not able to successfully call the "repovar" variable in the jq command.
cat quayrepo.txt | while read line
do
export repovar="$line"
jq -r --arg repovar "$repovar" '.data.Layer| .Features[] | "\(.Name), \(.Version), $repovar"' severity.json > volume.csv
done
The script uses a text file to loop through the repo names
quayrepo.txt---> file has the list of names in this case the file has a value of "Reponame1"
sample input severity.json file:
{
"status": "scanned",
"data": {
"Layer": {
"IndexedByVersion": 3,
"Features": [
{
"Name": "elfutils",
"Version": "0.168-1",
"Vulnerabilities": [
{
"NamespaceName": "debian:9",
"Severity": "Medium",
"Name": "CVE-2016-2779"
}
]
}
]
}
}
}
desired output:
elfutils, 0.168-1, Medium, Reponame1
Required output: I need to retrieve the value of my environment variable as the last column in my output csv file
You need to surround $repovar with parenthesis, as the other values
repovar='qweqe'; jq -r --arg repovar "$repovar" '.data.Layer| .Features[] | "\(.Name), \(.Version), \($repovar)"' tmp.json
Result:
elfutils, 0.168-1, qweqe
There's no need for the export.
#!/usr/bin/env bash
while read line
do
jq -r --arg repovar "$line" '.data.Layer.Features[] | .Name + ", " + .Version + ", " + $repovar' severity.json
done < quayrepo.txt > volume.csv
with quayrepo.txt as
Reponame1
and severity.json as
{
"status": "scanned",
"data": {
"Layer": {
"IndexedByVersion": 3,
"Features": [
{
"Name": "elfutils",
"Version": "0.168-1",
"Vulnerabilities": [
{
"NamespaceName": "debian:9",
"Severity": "Medium",
"Name": "CVE-2016-2779"
}
]
}
]
}
}
}
produces volume.csv containing
elfutils, 0.168-1, Reponame1
To #peak's point, changing > to >> in ...severity.json >> volume.csv will create a multi-line csv instead of just overwriting until the last line
You don't need a while read loop in bash at all; jq itself can loop over your input lines, even when they aren't JSON, letting you run jq only once, not once per line in quayrepo.txt.
jq -rR --slurpfile inJson severity.json <quayrepo.txt >volume.csv '
($inJson[0].data.Layer | .Features[]) as $features |
[$features.Name, $features.Version, .] |
#csv
'
jq -R specifies raw input, letting jq directly read lines from quayrepo.txt into .
jq --slurpfile varname filename.json reads filename.json into an array of JSON objects parsed from that file. If the file contains only one object, one needs to refer to $varname[0] to refer to it.
#csv converts an array to a CSV output line, correctly handling data with embedded quotes or other oddities that require special processing.
I have created a simple script to store response from a third party API
The request is like this..
https://externalservice.io/orders?key=password&records=50&offset=0
The response is as follows:
{
"results": [
{
"engagement": {
"id": 29090716,
"portalId": 62515,
"active": true,
"createdAt": 1444223400781,
"lastUpdated": 1444223400781,
"createdBy": 215482,
"modifiedBy": 215482,
"ownerId": 70,
"type": "NOTE",
"timestamp": 1444223400781
},
},
],
"hasMore": true,
"offset": 4623406
}
If there is a hasMore attribute, I need to read the offset value to get the next set of records.
Right now I've created a script that simply loops over the estimated number of records (I believed there is) and thought incrementing the offset would work but this is not the case as the offset is not incremental.
#!/bin/bash
for i in {1..100}; do
curl -s "https://externalservice.io/orders?key=password&records=50&offset=$i" >>outfile.txt 2>&1
done
Can someone explain how I can read continue the script reading the offset value until hasMore=false?
You can read a value from a json using the jq utility:
$ jq -r ".hasMore" outfile
true
Here is what you could use:
more="true"
offset=0
while [ $more = "true" ]; do
echo $offset
response=$(curl -s "https://example.com/orders?offset=$offset")
more=$(echo $response | tr '\r\n' ' ' | jq -r ".hasMore")
offset=$(echo $response | tr '\r\n' ' ' | jq -r ".offset")
done
You can use jq utility to extract specific attribute from you json response:
$ jq -r ".hasMore" outfile
true
jq expects perfectly valid json input, otherwise it will print error.
Most common mistake is to echo json stored in variable. A mistake, because echo will interpret all escaped newlines in your json and will send unescaped newlines within values causing jq to throw parse error: Invalid string: control characters from U+0000 through U+001F must be escaped at line message.
To avoid modification to json (and avoiding an error) we need to use printf instead of echo.
Here is the solution without breaking json content:
more="true"
offset=0
while [ $more = "true" ]; do
echo $offset
response=$(curl -s "https://example.com/orders?offset=$offset")
more=$(printf "%s\n" "$response" | jq -r ".hasMore")
offset=$(printf "%s\n" "$response" | jq -r ".offset")
done
i'm trying to build script that takes specific attribute value and store it in the array , this is the following JSON file:
[
{
"id": 1,
"name": "myna",
"description": "Simple Question",
"speaker": "USER",
},
{
"all_Id's": [
"11111"
],
"user": "me",
},
{
"id": 2,
"name": "mry",
"description": "Simple",
"speaker": "aaa",
}
]
as you see object in json file don't have the same attributes so i'm looking only on object has "name " attribute,the following script reads the Json file and return the values of attribute name only ,but i build something wrond as theERROR always on the "{" of the last object in file I don't know why , what i am i doing wrong?
the expected output is : [myna, mry]
#!/bin/bash
declare -a OB_I=()
declare counter1=0
jq -r '.name' file.json ; while read -r val ; do
if [[ ! $val ]]
then
OB_I[$counter]=$val ;
counter=$((counter+1));
fi
done;
$ printf '%s\n' "${OB_I[#]}"
The input of jq is a list, which doesn't have any keys, let alone one named name. You want
jq -r '.[].name'
instead.
Unrelated, you don't need the variable counter. You can simply append to your array with OB_I+=("$val").