How to convert output of iostat command to json

Question

I need to convert the output of iostat command to json. Information is needed only for sd[a-z] discs. It is advisable to do the conversion using awk.

iostat -xd
Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sdb               0.01     0.15    0.00    0.00     0.07     0.61   246.51     0.00    3.33    2.85    3.71   1.07   0.00
sda               0.00     0.40    1.59   22.31    47.43  1507.39   130.10     0.03    1.22    4.05    1.02   0.20   0.47
sdc               0.00     0.59    0.14   10.06    18.40   199.05    42.62     0.03    2.48    7.68    2.40   0.16   0.17
sdd               0.01     0.97    1.58   13.13    53.29   190.60    33.15     0.12    7.92   12.03    7.42   0.79   1.17
sde               0.00     0.06    0.00    0.48     0.76    84.47   354.97     0.00    4.33    7.59    4.30   0.86   0.04
dm-0              0.00     0.00    0.00    0.00     0.05     0.03    22.11     0.00    1.03    1.98    0.38   0.84   0.00
dm-1              0.00     0.00    0.02    0.15     0.07     0.61     8.01     0.00    3.22    2.67    3.28   0.03   0.00
dm-2              0.00     0.00    0.14    0.01     6.04     0.10    82.39     0.00    2.54    2.71    0.57   0.49   0.01
dm-3              0.00     0.00    0.14   10.65    18.40   199.05    40.30     0.03    2.56    7.68    2.49   0.15   0.17
dm-4              0.00     0.00    0.01    0.01     0.69     0.05    70.39     0.00    2.22    5.30    0.27   0.35   0.00
dm-5              0.00     0.00    0.00    0.00     0.00     0.00    43.29     0.00    0.70    1.43    0.37   0.63   0.00

I am expecting the following result:

[ { "device":"sdb", "rrqm_s":"0.01", "wrqm_s":"0.15", "r_s":"0.00", "w_s":"0.00", "rkb_s":"0.07", "wkb_s":"0.61", "avgrq_sz":"246.39", "avgqu_sz":"0.00", "await":"3.33", "r_await":"2.85", "w_await":"3.71", "svctm":"1.07", "util":"0.00" },
{ "device":"sda", "rrqm_s":"0.00", "wrqm_s":"0.40", "r_s":"1.59", "w_s":"22.31", "rkb_s":"47.43", "wkb_s":"1507.39", "avgrq_sz":"130.09", "avgqu_sz":"0.03", "await":"1.22", "r_await":"4.05", "w_await":"1.02", "svctm":"0.20", "util":"0.47" },
{ "device":"sdc", "rrqm_s":"0.00", "wrqm_s":"0.59", "r_s":"0.14", "w_s":"10.06", "rkb_s":"18.40", "wkb_s":"199.03", "avgrq_sz":"42.62", "avgqu_sz":"0.03", "await":"2.48", "r_await":"7.68", "w_await":"2.40", "svctm":"0.16", "util":"0.17" },
{ "device":"sdd", "rrqm_s":"0.01", "wrqm_s":"0.97", "r_s":"1.58", "w_s":"13.13", "rkb_s":"53.29", "wkb_s":"190.61", "avgrq_sz":"33.15", "avgqu_sz":"0.12", "await":"7.92", "r_await":"12.03", "w_await":"7.42", "svctm":"0.79", "util":"1.17" },
{ "device":"sde", "rrqm_s":"0.00", "wrqm_s":"0.06", "r_s":"0.00", "w_s":"0.48", "rkb_s":"0.76", "wkb_s":"84.48", "avgrq_sz":"355.01", "avgqu_sz":"0.00", "await":"4.33", "r_await":"7.59", "w_await":"4.30", "svctm":"0.86", "util":"0.04" } ]

Answer 1

I used the following code:

iostat -dx | awk '
BEGIN { printf "[ " } 
/^Device:/ {
    gsub(":", "")
    gsub("/", "_") 
    gsub("-", "_")
    gsub("%", "")
    split(tolower($0), FIELDS)
} 
/^sd/ {
    if ( ++PRINT_LINE > 1 ) { print " }," }
    printf "{ "
    for (II=1; II<=NF; ++II) {
        printf "\"" FIELDS[II] "\":\"" $II "\""
        if (II != NF) {printf ", "}
    }
}
END { printf " } ]" }'

I got the following JSON:

[ { "device":"sdb", "rrqm_s":"0.01", "wrqm_s":"0.15", "r_s":"0.00", "w_s":"0.00", "rkb_s":"0.07", "wkb_s":"0.61", "avgrq_sz":"246.39", "avgqu_sz":"0.00", "await":"3.33", "r_await":"2.85", "w_await":"3.71", "svctm":"1.07", "util":"0.00" },
{ "device":"sda", "rrqm_s":"0.00", "wrqm_s":"0.40", "r_s":"1.59", "w_s":"22.31", "rkb_s":"47.43", "wkb_s":"1507.39", "avgrq_sz":"130.09", "avgqu_sz":"0.03", "await":"1.22", "r_await":"4.05", "w_await":"1.02", "svctm":"0.20", "util":"0.47" },
{ "device":"sdc", "rrqm_s":"0.00", "wrqm_s":"0.59", "r_s":"0.14", "w_s":"10.06", "rkb_s":"18.40", "wkb_s":"199.03", "avgrq_sz":"42.62", "avgqu_sz":"0.03", "await":"2.48", "r_await":"7.68", "w_await":"2.40", "svctm":"0.16", "util":"0.17" },
{ "device":"sdd", "rrqm_s":"0.01", "wrqm_s":"0.97", "r_s":"1.58", "w_s":"13.13", "rkb_s":"53.29", "wkb_s":"190.61", "avgrq_sz":"33.15", "avgqu_sz":"0.12", "await":"7.92", "r_await":"12.03", "w_await":"7.42", "svctm":"0.79", "util":"1.17" },
{ "device":"sde", "rrqm_s":"0.00", "wrqm_s":"0.06", "r_s":"0.00", "w_s":"0.48", "rkb_s":"0.76", "wkb_s":"84.48", "avgrq_sz":"355.01", "avgqu_sz":"0.00", "await":"4.33", "r_await":"7.59", "w_await":"4.30", "svctm":"0.86", "util":"0.04" } ]

Answer 2

just run it with -o JSON

iostat -xd -o JSON