fix(unitproc/bkt-replace_apos):Update comments
[BK-2020-03.git] / unitproc / bkt-count_jobs
1 #!/usr/bin/env bash
2
3 # Note: GNU Parallel obviates the need for this script. The main
4 # motivation to writing this script was to manage the number of CPU
5 # threads being spawned by a list of files being feed to a while loop.
6
7 # Functions
8 yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
9 die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
10 try() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
11 count_jobs() {
12 # Desc: Count and return total number of jobs
13 # Usage: count_jobs
14 # Input: None.
15 # Output: stdout integer number of jobs
16 # Depends: Bash 5.1.16
17 # Example: while [[$(count_jobs) -gt 0]]; do echo "Working..."; sleep 1; done;
18 # Version: 0.0.1
19
20 local job_count;
21 job_count="$(jobs -r | wc -l | tr -d ' ' )";
22 #yell "DEBUG:job_count:$job_count";
23 if [[ -z $job_count ]]; then job_count="0"; fi;
24 echo "$job_count";
25 }; # Return number of background jobs
26 test_job() {
27 #yell "DEBUG:starting test_job() with:$1";
28 # Do work on $1 file
29 if [[ -f $1 ]]; then cat "$1" 1>/dev/random 2>&1; fi; # read file
30 sleep "$(shuf -i1-10 -n1)"; # debug
31 }; # Test job
32 count_jobs_display_update() {
33 # Depends: various variables
34 if [[ $(( SECONDS % jobs_update_interval )) -eq $jobs_update_init_delay ]] && \
35 [[ $permit_update == "true" ]]; then
36 jobs_beg="$jobs_n";
37 jobs_run="$(count_jobs)";
38 jobs_end="$((jobs_beg - jobs_run))";
39 yell "STATUS:$jobs_beg jobs begun. $jobs_end jobs ended. $jobs_run jobs running.";
40 permit_update="false";
41 fi;
42 if [[ $(( SECONDS % jobs_update_interval )) -eq $((jobs_update_init_delay + 1)) ]]; then
43 permit_update="true";
44 fi;
45 }; # periodically display updates
46
47
48 # Test Code
49 path_target="/tmp"; # path to dir with files to run test_job() on
50
51 ## Setup file list
52 list_paths="$(find "$path_target" -type f 2>/dev/null)";
53
54 ## Perform test_job() on each file
55 jobs_max=100; # adjust me (e.g. "4" on 4-core CPU)
56 jobs_update_interval=5; # seconds.
57 jobs_update_init_delay=1; # seconds.
58 permit_update="true"; # flag to make updates happen periodically
59 jobs_n=0; # loop counter
60 jobs_check_delay=0.001; # seconds between each job count check if running jobs > jobs_max
61 while read -r line; do
62 ((jobs_n++));
63 #yell "DEBUG:jobs_n:$jobs_n"
64
65 ## Wait until job count falls below $jobs_max
66 while [[ "$(count_jobs)" -gt $jobs_max ]]; do
67 #yell "DEBUG:sleeping since $(count_jobs) > $jobs_max";
68 sleep "$jobs_check_delay";
69 count_jobs_display_update;
70 done;
71
72 ## Start new parallel job on file $line
73 test_job "$line" 1>/dev/null 2>&1 &
74
75 ## Get job status updates every $jobs_update_interval seconds
76 count_jobs_display_update;
77
78 #sleep 1; # debug
79 done < <( shuf < <(echo -n "$list_paths") );
80 yell "STATUS:All jobs ($jobs_n) started. $(count_jobs) jobs running.";
81
82 # Detect when no outstanding jobs
83 while [[ "$(count_jobs)" -gt 0 ]]; do
84 sleep 1;
85 count_jobs_display_update;
86 done;
87 yell "STATUS:No more jobs visible.";
88
89 # Author: Steven Baltakatei Sandoval
90 # License: GPLv3+