Use wait -n for image job throttling

2 files changed, 107 insertions, 0 deletions

diff --git a/tests/cli.sh b/tests/cli.sh
index 975b724..63383fa 100755
--- a/tests/cli.sh
+++ b/tests/cli.sh
@@ -868,6 +868,62 @@ test_generate_image_jobs_limits_parallel_imagemagick() {
     test::teardown
 }
 
+test_generate_image_jobs_waits_for_any_finished_imagemagick() {
+    local config_file
+    local fake_bin
+    local finish_01_line
+    local lock_file
+    local log_file
+    local log_output
+    local start_03_line
+
+    test::setup
+    fake_bin="$TEST_TMPDIR/bin"
+    config_file="$TEST_TMPDIR/photoalbum.conf"
+    lock_file="$TEST_TMPDIR/wait-n.lock"
+    log_file="$TEST_TMPDIR/wait-n.log"
+
+    test::install_wait_n_imagemagick_spy "$fake_bin"
+    mkdir -p "$TEST_TMPDIR/incoming"
+    printf 'fake image\n' > "$TEST_TMPDIR/incoming/01.jpg"
+    printf 'fake image\n' > "$TEST_TMPDIR/incoming/02.jpg"
+    printf 'fake image\n' > "$TEST_TMPDIR/incoming/03.jpg"
+    printf 'fake image\n' > "$TEST_TMPDIR/incoming/04.jpg"
+    test::write_album_config \
+        "$config_file" "$TEST_TMPDIR/incoming" "$TEST_TMPDIR/dist" \
+        'Wait n image jobs album' 40
+
+    (
+        cd "$TEST_TMPDIR"
+        PATH="$fake_bin:$PATH" \
+            TEST_WAIT_N_MAGICK_LOCK="$lock_file" \
+            TEST_WAIT_N_MAGICK_LOG="$log_file" \
+            "$TEST_PHOTOALBUM" --image-jobs 2 --generate
+    )
+
+    log_output=$(<"$log_file")
+    test::assert_contains 'start photos/03.jpg' "$log_output"
+    test::assert_contains 'finish photos/01.jpg' "$log_output"
+    start_03_line=$(
+        grep -n '^start photos/03\.jpg$' "$log_file" \
+            | head -n 1 \
+            | cut -d: -f1
+    )
+    finish_01_line=$(
+        grep -n '^finish photos/01\.jpg$' "$log_file" \
+            | head -n 1 \
+            | cut -d: -f1
+    )
+
+    if (( start_03_line >= finish_01_line )); then
+        echo 'FAIL: expected photos/03.jpg to start before photos/01.jpg finished' >&2
+        cat "$log_file" >&2
+        exit 1
+    fi
+
+    test::teardown
+}
+
 test_repeated_output_flags_use_last_value() {
     local config_file
     local fake_bin
@@ -2967,6 +3023,9 @@ main() {
         '--generate --image-jobs limits ImageMagick parallelism' \
         test_generate_image_jobs_limits_parallel_imagemagick
     test::run_case \
+        '--generate --image-jobs waits for any finished ImageMagick job' \
+        test_generate_image_jobs_waits_for_any_finished_imagemagick
+    test::run_case \
         'repeated output flags use last value' \
         test_repeated_output_flags_use_last_value
     test::run_case \
diff --git a/tests/helpers.sh b/tests/helpers.sh
index 6306004..96f0ab4 100755
--- a/tests/helpers.sh
+++ b/tests/helpers.sh
@@ -272,6 +272,54 @@ MAGICK
     cp "$bin_dir/magick" "$bin_dir/convert"
 }
 
+test::install_wait_n_imagemagick_spy() {
+    local -r bin_dir="$1"; shift
+
+    mkdir -p "$bin_dir"
+
+    cat > "$bin_dir/magick" <<'MAGICK'
+#!/usr/bin/env bash
+set -euo pipefail
+
+if [ "${1:-}" = identify ]; then
+    exit 0
+fi
+
+lock_file="${TEST_WAIT_N_MAGICK_LOCK:?}"
+log_file="${TEST_WAIT_N_MAGICK_LOG:?}"
+dest="${@: -1}"
+dest_name="$(basename "$dest")"
+dest_dir="$(basename "$(dirname "$dest")")"
+dest_label="$dest_dir/$dest_name"
+
+(
+    flock 9
+    printf 'start %s\n' "$dest_label" >> "$log_file"
+) 9>"$lock_file"
+
+if [ "$dest_label" = 'photos/01.jpg' ]; then
+    sleep "${TEST_WAIT_N_SLOW_SECONDS:-0.4}"
+else
+    sleep "${TEST_WAIT_N_FAST_SECONDS:-0.02}"
+fi
+
+mkdir -p "$(dirname "$dest")"
+{
+    printf 'fake image\n'
+    printf 'args:'
+    printf ' %q' "$@"
+    printf '\n'
+} > "$dest"
+
+(
+    flock 9
+    printf 'finish %s\n' "$dest_label" >> "$log_file"
+) 9>"$lock_file"
+MAGICK
+    chmod 0755 "$bin_dir/magick"
+    cp "$bin_dir/magick" "$bin_dir/convert"
+}
+
 test::install_failing_imagemagick() {
     local -r bin_dir="$1"; shift