While there are several posts about this topic on Stack Overflow, none match my exact use case. I am using a Linux shell script to run SnowSQL to generate a json file.
========================
My json file needs to have a comma between json objects.
This:
{
"CAMPAIGN": "Welcome_New",
"UUID": "fe881781-bdc2-41b2-95f2-e0e8c19dc597"
}
{
"CAMPAIGN": "Welcome_Existing",
"UUID": "77a41c02-beb9-48bf-ada4-b2074c1a78cb"
}
...needs to look this:
{
"CAMPAIGN": "Welcome_New",
"UUID": "fe881781-bdc2-41b2-95f2-e0e8c19dc597"
},
{
"CAMPAIGN": "Welcome_Existing",
"UUID": "77a41c02-beb9-48bf-ada4-b2074c1a78cb"
}
Here is my complete ksh script:
#!/usr/bin/ksh
. /appl/.snf_logon
export SNOW_PKEY_FILE=$(mktemp ./pkey-XXXXXX)
trap "rm -f ${SNOW_PKEY_FILE}" EXIT
LibGetSnowCred
{
outFile=JSON_FILE_TYPE_TEST.json
inDir=/testing
outFileNm=#my_db.my_schema.my_file_stage/${outFile}
snowsql \
--private-key-path $SNOW_PKEY_FILE \
-o exit_on_error=true \
-o friendly=false \
-o timing=false \
-o log_level=ERROR \
-o echo=true <<!
COPY INTO ${outFileNm}
FROM (SELECT object_construct(
'UUID',UUID
,'CAMPAIGN',CAMPAIGN)
FROM my_db.my_schema.JSON_Test_Table
LIMIT 2)
FILE_FORMAT=(
TYPE=JSON
COMPRESSION=NONE
)
OVERWRITE=True
HEADER=False
SINGLE=True
MAX_FILE_SIZE=4900000000
;
get ${outFileNm} file://${inDir}/;
rm ${outFileNm};
!
if [ $? -eq 0 ]; then
echo "Export successful"
else
echo "ERROR in export"
fi
}
Is the best practice to add the comma during the SELECT or after the file is generated and how?
With or without that comma, the text is still not JSON but just a random text that looks like JSON. You export several rows, each row as an independent object. You need to gather all these objects into an array to produce a valid JSON.
A JSON that encodes an array of rows looks like this:
[
{
"CAMPAIGN": "Welcome_New",
"UUID": "fe881781-bdc2-41b2-95f2-e0e8c19dc597"
},
{
"CAMPAIGN": "Welcome_Existing",
"UUID": "77a41c02-beb9-48bf-ada4-b2074c1a78cb"
}
]
The easiest way to produce this output would be to ask the database, if it supports this option (to wrap all the records into a list before generating the JSON, to not export each record in a separate JSON).
If this is not possible then you have a file that contains multiple JSONs. You can use jq to convert these individual JSONs into a JSON similar to the one described above (encoding an array of objects).
It is as simple as that:
jq --slurp '.' input_file > output_file
The option --slurp tells jq to read all the JSONs from the file input_file in memory, to parse them and to put them into an array. That is the program input.
'.' is the jq program. It says "dump the current object". It does not do any processing to the input data. The current object is the array.
After it executes the program (which, in this case doesn't do anything), jq dumps the modified value (as JSON, of course) to the standard output (by default, on screen).
The > output_file part redirects this output to a file (named output_file) instead of showing it on screen.
You can see how it works on the jq playground.
I'm new to jq (around 24 hours). I'm getting the filtering/selection already, but I'm wondering about advanced I/O features. Let's say I have an existing jq query that works fine, producing a stream (not a list) of objects. That is, if I pipe them to a file, it produces:
{
"id": "foo"
"value": "123"
}
{
"id": "bar"
"value": "456"
}
Is there some fancy expression I can add to my jq query to output each object individually in a subdirectory, keyed by the id, in the form id/id.json? For example current-directory/foo/foo.json and current-directory/bar/bar.json?
As #pmf has pointed out, an "only-jq" solution is not possible. A solution using jq and awk is as follows, though it is far from robust:
<input.json jq -rc '.id, .' | awk '
id=="" {id=$0; next;}
{ path=id; gsub(/[/]/, "_", path);
system("mkdir -p " path);
print >> path "/" id ".json";
id="";
}
'
As you will need help from outside jq anyway (see #peak's answer using awk), you also might want to consider using another JSON processor instead which offers more I/O features. One that comes to my mind is mikefarah/yq, a jq-inspired processor for YAML, JSON, and other formats. It can split documents into multiple files, and since its v4.27.2 release it also supports reading multiple JSON documents from a single input source.
$ yq -p=json -o=json input.json -s '.id'
$ cat foo.json
{
"id": "foo",
"value": "123"
}
$ cat bar.json
{
"id": "bar",
"value": "456"
}
The argument following -s defines the evaluation filter for each output file's name, .id in this case (the .json suffix is added automatically), and can be manipulated to further needs, e.g. -s '"file_with_id_" + .id'. However, adding slashes will not result in subdirectories being created, so this (from here on comparatively easy) part will be left over for post-processing in the shell.
I was writing my custom code snippets for verilog files in VScode; VSCode uses JSON files for it.
I observed that $ before finish and dumpvars statements doesn't get printed when I use the snippet since it is a built-in keyword for including variables in strings in json file format,
I have tried adding \ before $ but that didn't work.
Is there any way I can insert $ in my snippets?
This is the relevant code block I am using:
"dump statements": {
"prefix": "dump",
"body": [
"initial begin",
" dumpfile(\"${1:filename}\");",
" \$dumpvars();",
"end"
],
"description": "Prints the dump file and variables statements."
},
Use a double backslash to escape it, like this \\$
"dump statements": {
"prefix": "dump",
"body": [
"initial begin",
" dumpfile(\"${1:filename}\");",
" \\$dumpvars();",
"end"
],
"description": "Prints the dump file and variables statements."
},
I am trying to form a JSON construct using jq that should ideally look like below:-
{
"api_key": "XXXXXXXXXX-7AC9-D655F83B4825",
"app_guid": "XXXXXXXXXXXXXX",
"time_start": 1508677200,
"time_end": 1508763600,
"traffic": [
"event"
],
"traffic_including": [
"unattributed_traffic"
],
"time_zone": "Australia/NSW",
"delivery_format": "csv",
"columns_order": [
"attribution_attribution_action",
"attribution_campaign",
"attribution_campaign_id",
"attribution_creative",
"attribution_date_adjusted",
"attribution_date_utc",
"attribution_matched_by",
"attribution_matched_to",
"attribution_network",
"attribution_network_id",
"attribution_seconds_since",
"attribution_site_id",
"attribution_site_id",
"attribution_tier",
"attribution_timestamp",
"attribution_timestamp_adjusted",
"attribution_tracker",
"attribution_tracker_id",
"attribution_tracker_name",
"count",
"custom_dimensions",
"device_id_adid",
"device_id_android_id",
"device_id_custom",
"device_id_idfa",
"device_id_idfv",
"device_id_kochava",
"device_os",
"device_type",
"device_version",
"dimension_count",
"dimension_data",
"dimension_sum",
"event_name",
"event_time_registered",
"geo_city",
"geo_country",
"geo_lat",
"geo_lon",
"geo_region",
"identity_link",
"install_date_adjusted",
"install_date_utc",
"install_device_version",
"install_devices_adid",
"install_devices_android_id",
"install_devices_custom",
"install_devices_email_0",
"install_devices_email_1",
"install_devices_idfa",
"install_devices_ids",
"install_devices_ip",
"install_devices_waid",
"install_matched_by",
"install_matched_on",
"install_receipt_status",
"install_san_original",
"install_status",
"request_ip",
"request_ua",
"timestamp_adjusted",
"timestamp_utc"
]
}
What I have tried unsuccessfully thus far is below:-
json_construct=$(cat <<EOF
{
"api_key": "6AEC90B5-4169-59AF-7AC9-D655F83B4825",
"app_guid": "komacca-s-rewards-app-au-ios-production-cv8tx71",
"time_start": 1508677200,
"time_end": 1508763600,
"traffic": ["event"],
"traffic_including": ["unattributed_traffic"],
"time_zone": "Australia/NSW",
"delivery_format": "csv"
"columns_order": ["attribution_attribution_action","attribution_campaign","attribution_campaign_id","attribution_creative","attribution_date_adjusted","attribution_date_utc","attribution_matched_by","attribution_matched_to","attributio
network","attribution_network_id","attribution_seconds_since","attribution_site_id","attribution_tier","attribution_timestamp","attribution_timestamp_adjusted","attribution_tracker","attribution_tracker_id","attribution_tracker_name","
unt","custom_dimensions","device_id_adid","device_id_android_id","device_id_custom","device_id_idfa","device_id_idfv","device_id_kochava","device_os","device_type","device_version","dimension_count","dimension_data","dimension_sum","ev
t_name","event_time_registered","geo_city","geo_country","geo_lat","geo_lon","geo_region","identity_link","install_date_adjusted","install_date_utc","install_device_version","install_devices_adid","install_devices_android_id","install_
vices_custom","install_devices_email_0","install_devices_email_1","install_devices_idfa","install_devices_ids","install_devices_ip","install_devices_waid","install_matched_by","install_matched_on","install_receipt_status","install_san_
iginal","install_status","request_ip","request_ua","timestamp_adjusted","timestamp_utc"]
}
EOF)
followed by:-
echo "$json_construct" | jq '.'
I get the following error:-
parse error: Expected separator between values at line 10, column 15
I am guessing it is because of the string literal which spans to multiple lines that jq is unable to parse it.
Use jq itself:
my_formatted_json=$(jq -n '{
"api_key": "XXXXXXXXXX-7AC9-D655F83B4825",
"app_guid": "XXXXXXXXXXXXXX",
"time_start": 1508677200,
"time_end": 1508763600,
"traffic": ["event"],
"traffic_including": ["unattributed_traffic"],
"time_zone": "Australia/NSW",
"delivery_format": "csv",
"columns_order": [
"attribution_attribution_action",
"attribution_campaign",
...,
"timestamp_utc"
]
}')
Your input "JSON" is not valid JSON, as indicated by the error message.
The first error is that a comma is missing after the key/value pair: "delivery_format": "csv", but there are others -- notably, JSON strings cannot be split across lines. Once you fix the key/value pair problem and the JSON strings that are split incorrectly, jq . will work with your text. (Note that once your input is corrected, the longest JSON string is quite short -- 50 characters or so -- whereas jq has no problems processing strings of length 10^8 quite speedily ...)
Generally, jq is rather permissive when it comes to JSON-like input, but if you're ever in doubt, it would make sense to use a validator such as the online validator at jsonlint.com
By the way, the jq FAQ does suggest various ways for handling input that isn't strictly JSON -- see https://github.com/stedolan/jq/wiki/FAQ#processing-not-quite-valid-json
Along the lines of chepner's suggestion since jq can read raw text data you could just use a jq filter to generate a legal json object from your script variables. For example:
#!/bin/bash
# whatever logic you have to obtain bash variables goes here
key=XXXXXXXXXX-7AC9-D655F83B4825
guid=XXXXXXXXXXXXXX
# now use jq filter to read raw text and construct legal json object
json_construct=$(jq -MRn '[inputs]|map(split(" ")|{(.[0]):.[1]})|add' <<EOF
api_key $key
app_guid $guid
EOF)
echo $json_construct
Sample Run (assumes executable script is in script.sh)
$ ./script.sh
{ "api_key": "XXXXXXXXXX-7AC9-D655F83B4825", "app_guid": "XXXXXXXXXXXXXX" }
Try it online!
i am writing personal parser for json on bash. So, i need to make grep of line. For example, part of my json-file.
{
"host": "127.0.0.1",
"hhost": "127.0.0.2",
}
Of course, after trying cat json.txt | grep host, i received:
"host": "127.0.0.1",
"hhost": "127.0.0.1",
I found, how to find only host without hhost. I used
cat json.txt | grep '"host"'
Everything is good
"host": "127.0.0.1",
But i want to use it in bash script:
#!/bin/bash
#in a future, i want to read variable var from reading from console
var=host
search='"$var"'
echo $search
In a result, i have:
"$var"
What i did wrong ? Can you advice me please ?
You could use jq, to parse the JSON file for this you will need first a proper valid json
{
"host": "127.0.0.1",
"hhost": "127.0.0.2"
}
Then you could just do something like:
#/bin/sh
HOST=$(jq '.host' data.json)
echo $HOST
...
if you put a variable inside single quotes in bash, I does not get evaluated, you should just use:
search="$var"
if you want the variable to be enclosed by quotes, just escape them like this:
search="\"$var\""