dusybox 0.0.1

Description

Simple implementations of System Ultilities in Dlang.

The primary purpose is to understand Dlang and to learn system programming.

• Getting started
• free Display system memory information
• watch Watch command output
• TODO
• Examples
• plotbar Draw 2-d bar chart
• TODO
• Examples
• jq Simple and not stupid json query tool
• TODO
• Examples

Getting started

To use any ultilities below, you need a dlang compiler and also the dub package manager. The compiler can be installed by your system package manager, for e.g,

$ pacman -S dmd   # on ArchLinux

To intsall dub please follow this link https://github.com/dlang/dub#installation.

free

Print information about system memory.

It's similar to the free command on your Linux system.

The original free tool is written in C and it uses a bsearch routine to look up various fields in /proc/meminfo. We don't use the same strategy in this version: Instead, we use a static enum that defines an ordered list of items to fetch. This order will not be portable and that's the reason this tool may not work with your kernel.

This tool is tested on Linux 4.12.8-2.

TODO

• [ ] Support different Linux versions
• [ ] Print human-readable memory size

Examples

$ dub run dusybox:free
              total        used        free      shared  buff/cache   available
Mem:       16337684     4161480     1770368      726864    10405836    11925640

watch

Execute a shell command and print its output to the standard output device every one second. This is similar to the popular watch command.

This tool uses nice-curses library. It can handle some fancy output, but it seems it can't handle big output and/or any special characters.

TODO

• [x] Redirect output from stderr (This works out-of-the-box)
• [x] Print time information of the last interaction
• [x] Print basic information about input command and iterator number.
• [x] Wait 1 second after every execution. No more --interval 1 :)
• [x] Specify maxium number of executions with -n <number>
• [ ] Fix problem with complex command ps xauw
• [ ] Exit if output matches some regular expression
• [ ] Exit if user presses q or Q
• [x] Tool doesn't work with pipe commands, e.g, ps x | grep foo: it reports command not found error. As a work-around you can use bash -c "ps x | grep ff" instead.

Examples

$ dub run dusybox:watch -- free -m
$ dub run dusybox:watch -- ps x

$ dub run dusybox:watch -- -n 10 'ps xwa | grep "f[i]r"'
:: No 4/10, Cmd ["ps xwa | grep \"f[i]r\""]
15774 ?        SNsl   3:01 /usr/lib/firefox/firefox
15776 ?        ZN     0:00 [firefox] <defunct>

...
:: Reached maximum number of interation (2) at 2017-Sep-05 18:04:47.0811478.

plotbar

This tool is inspired by https://github.com/lebinh/goplot. It visualizes your data as a simple bar chart. goplot draws relative bars (compare bar height to the highest bar), why this tool draws absolute bars (compare bar height to the sum of all bars).

The tool reads data from STDIN (the only source so far), and fetches every entry in format

key value

It will generate error messages to STDERR in case some line doesn't match the above format and/or their value is invalid.

In this version, tab (\t) is not support. You must use space(s) between key and value.

TODO

• [ ] Continous mode (keep drawing new bar while reading from stdin)
• [ ] Support tab delimeter in key value line
• [ ] Support negative data (2-direction bar chart)
• [x] Display actual value after the bar
• [x] Set the minium percent number to display (-m min)
• [ ] Display last n items (like sort | tail)
• [ ] Sort the output (if the input is sorted)
• [x] Additive mode (Sum of duplicated items)
• [x] Fix bug when parsing input data (previous value is reused.)
• [x] Move common part to a library file

Examples

Find the biggest folder items, display ones consume great than 2% of total storage. (The idea for this example comes from https://github.com/lebinh/goplot.) Please note that you can't use \t character in this example: The input parser doesn't understand tab.

$ dub run dusybox:plotbar -- -m 2 < <(2>/dev/null du -s /home/* | awk '{printf("%s %s\n", $2, $1)}')

/home/pi.fast :  9 % ========= (9466072)
     /home/pi : 13 % ============= (14541032)
 /home/btsync : 64 % ================================================================ (69425660)
  /home/ebook :  8 % ======== (8600288)
 /home/backup :  2 % == (2615004)

Display the ElasticSearch indices the have most documents. Skip all indices that consumes less than 2% in the total number of documents.

$ curl -s 'elk.example.net:9201/_cat/indices?h=index,docs.count' | dusybox_plotbar -m 2

           aws-lambda-test-uat-test-20170824 :  9 % ========= (4986415)
api-gateway-execution-logs-test-uat-20170824 :  4 % ==== (2486179)
           aws-lambda-test-uat-test-20170824 :  2 % == (1177304)
           aws-lambda-test-dev-test-20170815 :  4 % ==== (2227446)

Display the biggest indexes (in stored size):

$ curl -s 'elk.example.net:9201/_cat/indices?h=index,store.size&bytes=k' | dusybox_plotbar -m 2

aws-lambda-test-uat-test-20170824 :  2 % == (2847921)
                     emr-20170904 :  2 % == (3364511)
aws-lambda-test-uat-test-20170824 :  4 % ==== (5544297)
aws-lambda-test-uat-test-20170821 :  2 % == (2853427)

Now find the biggest source (by discarding date suffixes):

$ curl -s 'elk.example.net:9201/_cat/indices?h=index,store.size&bytes=k' \
  | sed -re 's#-[0-9]{8}##g' \
  | dusybox_plotbar -m 5 2>/dev/null

  aws-lambda-test-uat-test :  5 % ===== (3145751)
                       emr : 11 % =========== (6974423)
 aws-lambda-test-uat-test2 : 11 % =========== (6622399)
cloudtrail-defaultloggroup : 11 % =========== (6726637)

Find the package that has most files on ArchLinux system

$ pacman -Ql | grep -vE '/$' | awk '{printf("%s 1\n", $1 );}' | dusybox_plotbar -m 2
            evince :  2 % == (3058)
           efl-git :  2 % == (3563)
           python2 :  3 % === (4646)
adwaita-icon-theme :  4 % ==== (5426)
              mono :  2 % == (2443)
             linux :  3 % === (3984)
     linux-headers :  9 % ========= (12296)
            python :  5 % ===== (6784)
               ghc :  4 % ==== (5728)
 claws-mail-themes :  3 % === (4689)
           openssl :  2 % == (3252)
               qt4 :  3 % === (3825)
              perl :  2 % == (2393)
            libxcb :  2 % == (2371)
           ncurses :  3 % === (3678)
             cmake :  2 % == (2267)
         man-pages :  2 % == (3491)
               gcc :  2 % == (2198)

Find the biggest packages on ArchLinux system

$ pacman -Qi | awk '
    /Name/ {printf("%s", $NF);}
    /Installed Size.+KiB/ {printf(" %s\n", $(NF-1))}
    /Installed Size.+MiB/ {printf(" %s\n", $(NF-1) * 1024)}' \
  | ./dusybox_plotbar  -m 2
          mono :   4 % ==== (199782)
    ghc-static :  17 % ================= (843428)
       firefox :   3 % === (143370)
linux-firmware :   4 % ==== (206377)
      chromium :   4 % ==== (212572)
        python :   3 % === (131430)
           ghc :   8 % ======== (425339)
           gcc :   2 % == (119081)

jq

This is not https://github.com/stedolan/jq.

Instead, this tool reads line from STDIN and considers each line as a JSON string. This is useful as I need to process multiple JSON lines from nginx and/or ELK system.

If input line can be parsed, the result will be printed to stdout (if the tool has not any argument), or each item from arguments is looked up in the final JSON object. If the argument is

dusybox_jq .foo bar

then the .foo is used as a lookup key, while bar is printed literally.

TODO

• [ ] Handle delimeter
• [ ] Handle formatted string
• [ ] Handle object other than integer and/or string
• [ ] Nested support
• [x] Move common methods to a library file
• [x] Add unit tests
• [x] Literraly support
• [x] Process lines from STDIN as invidual documents. See also https://github.com/stedolan/jq/issues/744.

Examples

Print key .a and .b, print 1 literally.

$ echo '{"a": 9, "b": {"c": 1}}' | dub run dusybox:jq -- .a 1 .b
9       1       {"c":1}

Print the original JSON string

$ echo '{"a": 9, "b": {"c": 1}}' | dub run dusybox:jq --
'{"a": 9, "b": {"c": 1}}'

Generate simple statistics from nginx access log file. The format of log file is similar to this one.

$ dub run dusybox:jq -- .host 1 < /home/pi/df/acces.log | ./dusybox_plotbar -m 2
     kibana.int.example.net : 25 % ========================= (269)
    airflow.dev.example.net :  3 % === (33)
    grafana.int.example.net : 70 % ====================================================================== (755)
airflow.staging.example.net :  3 % === (28)

How about the requests or statuses?

$ dub run dusybox:jq -- .request_uri 1 < /home/pi/df/acces.log | ./dusybox_plotbar -m 2
/api/console/proxy?path=_aliases&method=GET :  4 % ==== (44)
/api/console/proxy?path=_mapping&method=GET :  4 % ==== (44)
                  /api/datasources/proxy/16 : 34 % ================================== (364)
                  /api/datasources/proxy/14 : 12 % ============ (132)
                  /api/datasources/proxy/13 :  5 % ===== (55)
                    /elasticsearch/_msearch :  4 % ==== (40)
                  /api/datasources/proxy/12 : 11 % =========== (122)

$ dub run dusybox:jq -- .status 1 < /home/pi/df/acces.log | ./dusybox_plotbar -m 2
200 : 93 % ============================================================================================= (1013)
304 :  4 % ==== (43)