xargs가 오류와 함께 종료되지 않습니다

문서 xargs( man xargs종료에 대해 실제로 말하는 내용을 참조하세요.

이 명령의 호출이 상태 255로 종료되면 xargs추가 입력을 읽지 않고 즉시 중지됩니다. 오류 메시지는 다음에서 전송되었습니다.표준 에러이런 일이 발생하면.

따라서 가능한 해결책 중 하나는 exec_script오류 발생 시 종료 상태 255를 반환하도록 변경하는 것입니다.

아무것도 변경할 수 없는 경우, 또 다른 가능한 해결책 exec_script은 일반 콘텐츠를 xargs셸 루프로 변환하는 것입니다.

find "$script_dir/build/scripts" -name '*.sh' -print0 |
    sort -z |
    while IFS= read -r -d '' item && exec_script _ "$item"; do :; done

exec_script0이 아닌 종료 값이 반환되면 루프가 중단됩니다.

또 다른 솔루션은논평이는 아마도 스크립트에서 종료 오류를 찾아 255로 바꾸는 가장 간단한 외부 수정일 것입니다.

find "$script_dir/build/scripts" -name '*.sh' -print0 |
    sort -z |
    xargs -r -0 -I% -n1 bash -c 'exec_script "$@" || exit 255' _ %

xargs꽤 번거로운 일입니다. 255로 종료할 때만 중지되기 때문에 set -eo pipefail서브쉘을 사용하여 set -eo pipefail실패를 캡슐화하고 255.

이 예에서는 다음 errornow줄을 주석 처리하여 차이점을 확인합니다.

#!/bin/bash
set -x
set -eo pipefail

parallel_uploads="4"
s3_bucket_name="backup"

all_files=(
"/12.pbd"
"/13.pbd"
"/14.pbd"
"/15.pbd"
"/16.pbd"
"/17.pbd"
"/18.pbd"
"/19.pbd"
"/20.pbd"
"/21.pbd"
"/22.pbd"
"/23.pbd"
"/24.pbd"
"/25.pbd"
"/26.pbd"
"/27.pbd"
)


# Workaround for the posix shell bug they call it feature
# https://unix.stackexchange.com/questions/65532/why-does-set-e-not-work-inside-subshells-with-parenthesis-followed-by-an-or
function acually_upload_to_s3()
{
    set -x;
    set -eu -o pipefail;

    printf 'Doing some\n';
    sleeptime="$(( RANDOM % 50 + 1 ))"
    sleep "$sleeptime";

    erroring_some;
    printf 'Doing more some\n';
}

function upload_to_s3()
{
    set -x;
    set -eu -o pipefail;
    # https://superuser.com/questions/403263/how-to-pass-bash-script-arguments-to-a-subshell
    /bin/bash -c "acually_upload_to_s3 $(printf "${1+ %q}" "$@")" || exit 255
}

function upload_all()
{
    export s3_bucket_name;
    export -f upload_to_s3;
    export -f acually_upload_to_s3;

    # https://unix.stackexchange.com/questions/566834/xargs-does-not-quit-on-error
    # https://stackoverflow.com/questions/11003418/calling-shell-functions-with-xargs
    # https://stackoverflow.com/questions/6441509/how-to-write-a-process-pool-bash-shell
    # https://stackoverflow.com/questions/356100/how-to-wait-in-bash-for-several-subprocesses-to-finish-and-return-exit-code-0
    printf "'%s'\n" "${all_files[@]}" | xargs \
            --max-procs="$parallel_uploads" \
            --max-args=1 \
            --replace={} \
            /bin/bash -c 'time upload_to_s3 "$s3_bucket_name" "{}"';
}

time upload_all \
    && printf '%s Successfully uploaded all files\n' "$(date)" \
    || printf '%s Error: Could not upload some files\n'  "$(date)";

출력 예:

$ bash upload_to_s3_glacier_deep.sh
+ set -eo pipefail
+ parallel_uploads=4
+ s3_bucket_name=backup
+ all_files=("/12.pbd" "/13.pbd" "/14.pbd" "/15.pbd" "/16.pbd" "/17.pbd" "/18.pbd" "/19.pbd" "/20.pbd" "/21.pbd" "/22.pbd" "/23.pbd" "/24.pbd" "/25.pbd" "/26.pbd" "/27.pbd")
+ upload_all
+ export s3_bucket_name
+ export -f upload_to_s3
+ export -f acually_upload_to_s3
+ printf ''\''%s'\''\n' /12.pbd /13.pbd /14.pbd /15.pbd /16.pbd /17.pbd /18.pbd /19.pbd /20.pbd /21.pbd /22.pbd /23.pbd /24.pbd /25.pbd /26.pbd /27.pbd
+ xargs --max-procs=4 --max-args=1 '--replace={}' /bin/bash -c 'time upload_to_s3 "$s3_bucket_name" "{}"'
+ set -eu -o pipefail
++ printf ' %q' backup /12.pbd
+ /bin/bash -c 'acually_upload_to_s3  backup /12.pbd'
+ set -eu -o pipefail
++ printf ' %q' backup /13.pbd
+ /bin/bash -c 'acually_upload_to_s3  backup /13.pbd'
+ set -eu -o pipefail
++ printf ' %q' backup /14.pbd
+ /bin/bash -c 'acually_upload_to_s3  backup /14.pbd'
+ set -eu -o pipefail
+ printf 'Doing some\n'
Doing some
+ sleeptime=3
+ sleep 3
+ set -eu -o pipefail
++ printf ' %q' backup /15.pbd
+ /bin/bash -c 'acually_upload_to_s3  backup /15.pbd'
+ set -eu -o pipefail
+ printf 'Doing some\n'
Doing some
+ sleeptime=49
+ sleep 49
+ set -eu -o pipefail
+ printf 'Doing some\n'
Doing some
+ sleeptime=13
+ sleep 13
+ set -eu -o pipefail
+ printf 'Doing some\n'
Doing some
+ sleeptime=30
+ sleep 30
+ erroring_some
environment: line 5: erroring_some: command not found
+ exit 255

real    0m3.146s
user    0m0.045s
sys 0m0.123s
xargs: /bin/bash: exited with status 255; aborting
+ erroring_some
environment: line 5: erroring_some: command not found
+ exit 255

real    0m13.149s
user    0m0.015s
sys 0m0.123s
xargs: /bin/bash: exited with status 255; aborting

real    0m13.271s
user    0m0.075s
sys 0m0.337s
++ date
+ printf '%s Error: Could not upload some files\n' 'Fri, Nov 19, 2021 22:00:30'
Fri, Nov 19, 2021 22:00:30 Error: Could not upload some files