update json with jq through shell script - json

Question

I created a shell script to create and update json files using jq. To create json files is working well. I have a variable that is passed as argument to jq command
#!/bin/sh
OPER=$1
FILE_PATH=$2
DATE_TIME=`date +%Y-%m-%d:%H:%M:%S`
DATE=`date +%Y-%m-%d`
CSV=$3
STEP=$4
STATUS=$5
CODE=$6
MESSAGE=$7
if [ "$#" -eq 7 ]; then
if [ "$OPER" == "create" ]; then
# echo "FILE_PATH: $FILE_PATH - CSV: $CSV - STEP: $STEP - STATUS: $STATUS - CODE: $CODE - MESSAGE: $MESSAGE"
REPORT="{\"date\": \"$DATE\", \"csv\": \"$CSV\", \"messages\": [{ \"timestamp\": \"$DATE_TIME\", \"step\": \"$STEP\", \"status\": \"$STATUS\", \"code\": \"$CODE\", \"message\": \"$MESSAGE\" }] }"
echo ${REPORT} | jq . > $FILE_PATH
elif [ "$OPER" == "update" ]; then
echo "FILE_PATH: $FILE_PATH - CSV: $CSV - STEP: $STEP - STATUS: $STATUS - CODE: $CODE - MESSAGE: $MESSAGE"
REPORT="{\"timestamp\": \"$DATE_TIME\", \"step\": \"$STEP\", \"status\": \"$STATUS\", \"code\": \"$CODE\", \"message\": \"$MESSAGE\"}"
echo "REPORTTTTT: "$REPORT
REPORT="jq '.messages[.messages| length] |= . + $REPORT' $FILE_PATH"
#echo $REPORT
echo `jq '.messages[.messages| length] |= . + $REPORT' $FILE_PATH` > $FILE_PATH
else
echo "operation not recognized: $OPER"
fi
else
echo "wrong parameters."
fi
jq . $FILE_PATH
But to update the json file I am getting an error. My $REPORT variable is correct. The cotes are correct. I think I must use another jq argument instead of |= . +. I used that command with plain text and it worked. But when I create the REPORT variable dynamically it throws an error.
Any clue? Thanks
REPORTTTTT: {"timestamp": "2017-02-17:12:11:11", "step": "2", "status": "OK", "code": "34", "message": "message 34 file.xml"}
jq: error: syntax error, unexpected INVALID_CHARACTER, expecting $end (Unix shell quoting issues?) at <top-level>, line 1:
'.messages[.messages|
jq: 1 compile error
jq: error: REPORT/0 is not defined at <top-level>, line 1:
.messages[.messages| length] |= . + $REPORT
jq: 1 compile error
Here is the example at the command line>>
$ jq . file.json
{
"date": "2017-02-17",
"csv": "file.csv",
"messages": [
{
"timestamp": "2017-02-17:12:31:21",
"step": "1",
"status": "OK",
"code": "33",
"message": "message 33"
}
]
}
$ export REPORT="{\"timestamp\": \"2017-02-17:11:51:14\", \"step\": \"2\", \"status\": \"OK\", \"code\": \"34\", \"message\": \"message 34 file.xml\"}"
$ echo $REPORT
{"timestamp": "2017-02-17:11:51:14", "step": "2", "status": "OK", "code": "34", "message": "message 34 file.xml"}
$ jq '.messages[.messages| length] |= . + $REPORT' file.json
jq: error: REPORT/0 is not defined at <top-level>, line 1:
.messages[.messages| length] |= . + $REPORT
jq: 1 compile error

Answer 1

Pass the argument $REPORT as a json argument using the --argjson flag supported from jq-1.5 onwards,
--argjson name JSON-text:
This option passes a JSON-encoded value to the jq program as a predefined variable.
Change your line to,
jq --argjson args "$REPORT" '.data.messages += [$args]' file

Answer 2

Don't generate JSON by hand; let jq do it. This is important if the values you want to add to the JSON need to be quoted properly, which will not happen if you are just performing string interpolation in the shell:
$ foo='"hi" he said'
$ json="{ \"text\": \"$foo\" }"
$ echo "$json"
{ "text": ""hi" he said" } # Wrong: should be { "text": "\"hi\" he said" }
Further, jq can generate the date and time strings; there is no need to run date (twice) as well.
#!/bin/sh
if [ $# -eq 7 ]; then
printf "Wrong number of parameters: %d\n" "$#" >&2
exit 1
fi
oper=$1 file_path=$2
# Generate the new message using arguments 3-7
new_message=$(
jq -n --arg csv "$3" --arg step "$4" \
--arg status "$5" --arg code "$6" \
--arg message "$7" '{
timestamp: now|strftime("%F:%T"),
csv: $csv, step: $step, status: $status, code: $code, message: $message}'
)
case $oper in
create)
jq -n --argjson new_msg "$new_message" --arg csv "$3" '{
date: now|strftime("%F"),
csv: $csv,
messages: [ $new_msg ]
}' > "$file_path"
;;
update)
jq --argjson new_msg "$new_message" \
'.messages += [ $new_msg ]' \
"$file_path" > "$file_path.tmp" && mv "$file_path.tmp" "$file_path" ;;
*) printf 'operation not recognized: %s\n' "$oper" >&2
exit 1 ;;
esac
jq '.' "$file_path"

Answer 3

Thanks #Inian. I changed a little bit but worked.... here is the solution.
if [ "$#" -eq 7 ]; then
if [ "$OPER" == "update" ]; then
echo "update Json"
echo "FILE_PATH: $FILE_PATH - CSV: $CSV - STEP: $STEP - STATUS: $STATUS - CODE: $CODE - MESSAGE: $MESSAGE"
REPORT="{\"timestamp\": \"$DATE_TIME\", \"step\": \"$STEP\", \"status\": \"$STATUS\", \"code\": \"$CODE\", \"message\": \"$MESSAGE\"}"
echo "REPORTTTTT: "$REPORT
echo `jq --argjson args "$REPORT" '.data.messages += [$args]' $FILE_PATH` > $FILE_PATH
else
echo "operation not recognized: $OPER"
fi
else
echo "wrong parameters."
fi