Generate JSON using Dynamic Variable in Shell script - linux

Question

I need to generate JSON output from my shell script.
I need to get Ram slot details of a particular machine and generate JSON using those details.
To get Ram details I am using system_profiler SPMemoryDataType
It produces details as follows.
BANK 0/DIMM0:
Size: 2 GB
Type: DDR3
Speed: 1600 MHz
Status: OK
Manufacturer: 0x802C
Part Number: 0x384A54463235363634485A2D3147364D3120
Serial Number: 0xE98388E6
BANK 1/DIMM0:
Size: 2 GB
Type: DDR3
Speed: 1600 MHz
Status: OK
Manufacturer: 0x802C
Part Number: 0x384A54463235363634485A2D3147364D3120
Serial Number: 0xE98388E5
From that I should form JSON like this
[
{"Bank":"0/DIMM0","Serial Number":"0xE98388E6","Status":"OK"},
{"Bank":"1/DIMM0","Serial Number":"0xE98388E5","Status":"OK"}
]
To extract separate details like bank, Serial Number, Status we can use
system_profiler SPMemoryDataType | awk '/Bank/
system_profiler SPMemoryDataType | awk '/Serial/
system_profiler SPMemoryDataType | awk '/Status/
I am sure that there is a need of Dynamic variable to do form json from the results. But since I am new to shell script I am confused. Is there any way to generate JSON from the output?

Answer 1

#!/usr/bin/awk -f
$1 == "BANK" {
bank = $2
sub(/:/, "", bank)
while (getline > 0) {
if ($1 == "Serial" && $2 == "Number:") {
serial_number = $3
} else if ($1 == "Status:") {
status = $2
}
if (serial_number != "" && status != "") {
entries[++e] = "{\"Bank\":\"" bank "\",\"Serial Number\":\"" serial_number "\",\"Status\":\"" status "\"}"
break
}
}
bank = serial_number = status = ""
}
END {
print "["
if (e > 0) {
printf "%s", entries[1]
for (i = 2; i <= e; ++i) {
printf ",\n%s", entries[i]
}
print ""
}
print "]"
}
Usage:
awk -f script.awk file
system_profiler SPMemoryDataType | awk -f script.awk
Example output:
[
{"Bank":"0/DIMM0","Serial Number":"0xE98388E6","Status":"OK"},
{"Bank":"1/DIMM0","Serial Number":"0xE98388E5","Status":"OK"}
]
Using within a shell script:
#!/bin/bash
system_profiler SPMemoryDataType | awk '$1 == "BANK" {
bank = $2
sub(/:/, "", bank)
while (getline > 0) {
if ($1 == "Serial" && $2 == "Number:") {
serial_number = $3
} else if ($1 == "Status:") {
status = $2
}
if (serial_number != "" && status != "") {
entries[++e] = "{\"Bank\":\"" bank "\",\"Serial Number\":\"" serial_number "\",\"Status\":\"" status "\"}"
break
}
}
bank = serial_number = status = ""
}
END {
print "["
if (e > 0) {
printf "%s", entries[1]
for (i = 2; i <= e; ++i) {
printf ",\n%s", entries[i]
}
print ""
}
print "]"
}'
A one-liner:
system_profiler SPMemoryDataType | awk '$1=="BANK"{bank=$2;sub(/:/,"",bank);while(getline>0){if($1=="Serial"&&$2=="Number:"){serial_number=$3}else if($1=="Status:"){status=$2};if(serial_number!=""&&status!=""){entries[++e]="{\"Bank\":\""bank"\",\"SerialNumber\":\""serial_number"\",\"Status\":\""status"\"}";break}};bank=serial_number=status=""}END{print "[";if(e>0){printf "%s",entries[1];for(i=2;i<=e;++i){printf ",\n%s",entries[i]};print""};print "]"}'

Answer 2

There are some few libraries to do so.. One such thing is https://github.com/jeganathgt/libjson-sh . It is standalone shell script library, provides easy handy API's to generate json output in console.
Ex :
json_init
json_add_string "serial" "$<cmd>"
json_add_string "bankinfo" "$<cmd>"
json_add_string "status" "$<cmd>"
json_dump