From: Adrian Ratiu Date: Thu, 25 Sep 2025 12:53:49 GMT Subject: [PATCH 06/10] run-command: allow capturing of collated output Message-ID: <20250925125352.1728840-7-adrian.ratiu@collabora.com> In-Reply-To: <20250925125352.1728840-1-adrian.ratiu@collabora.com> From: Emily Shaffer Some callers, for example server-side hooks which wish to relay hook output to clients across a transport, want to capture what would normally print to stderr and do something else with it. Allow that via a callback. By calling the callback regardless of whether there's output available, we allow clients to send e.g. a keepalive if necessary. Because we expose a strbuf, not a fd or FILE*, there's no need to create a temporary pipe or similar - we can just skip the print to stderr and instead hand it to the caller. Signed-off-by: Emily Shaffer Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Adrian Ratiu --- builtin/fetch.c | 2 +- builtin/submodule--helper.c | 2 +- hook.c | 2 +- run-command.c | 33 ++++++++++++++++++++++++--------- run-command.h | 22 +++++++++++++++++++++- submodule.c | 2 +- t/helper/test-run-command.c | 15 +++++++++++++++ t/t0061-run-command.sh | 7 +++++++ 8 files changed, 71 insertions(+), 14 deletions(-) diff --git a/builtin/fetch.c b/builtin/fetch.c index 24645c4653..53bd5552c4 100644 --- a/builtin/fetch.c +++ b/builtin/fetch.c @@ -2129,7 +2129,7 @@ static int fetch_multiple(struct string_list *list, int max_children, if (max_children != 1 && list->nr != 1) { struct parallel_fetch_state state = { argv.v, list, 0, 0, config }; - const struct run_process_parallel_opts opts = { + struct run_process_parallel_opts opts = { .tr2_category = "fetch", .tr2_label = "parallel/fetch", diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c index 07a1935cbe..76cae9f015 100644 --- a/builtin/submodule--helper.c +++ b/builtin/submodule--helper.c @@ -2700,7 +2700,7 @@ static int update_submodules(struct update_data *update_data) { int i, ret = 0; struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT; - const struct run_process_parallel_opts opts = { + struct run_process_parallel_opts opts = { .tr2_category = "submodule", .tr2_label = "parallel/update", diff --git a/hook.c b/hook.c index 54568d5bc0..199c210b97 100644 --- a/hook.c +++ b/hook.c @@ -135,7 +135,7 @@ int run_hooks_opt(struct repository *r, const char *hook_name, }; const char *const hook_path = find_hook(r, hook_name); int ret = 0; - const struct run_process_parallel_opts opts = { + struct run_process_parallel_opts opts = { .tr2_category = "hook", .tr2_label = hook_name, diff --git a/run-command.c b/run-command.c index 6c455a0e43..c0ef771ff4 100644 --- a/run-command.c +++ b/run-command.c @@ -1578,7 +1578,10 @@ static void pp_cleanup(struct parallel_processes *pp, * When get_next_task added messages to the buffer in its last * iteration, the buffered output is non empty. */ - strbuf_write(&pp->buffered_output, stderr); + if (opts->consume_sideband) + opts->consume_sideband(&pp->buffered_output, opts->data); + else + strbuf_write(&pp->buffered_output, stderr); strbuf_release(&pp->buffered_output); sigchain_pop_common(); @@ -1717,13 +1720,17 @@ static void pp_buffer_stderr(struct parallel_processes *pp, } } -static void pp_output(const struct parallel_processes *pp) +static void pp_output(const struct parallel_processes *pp, + const struct run_process_parallel_opts *opts) { size_t i = pp->output_owner; if (pp->children[i].state == GIT_CP_WORKING && pp->children[i].err.len) { - strbuf_write(&pp->children[i].err, stderr); + if (opts->consume_sideband) + opts->consume_sideband(&pp->children[i].err, opts->data); + else + strbuf_write(&pp->children[i].err, stderr); strbuf_reset(&pp->children[i].err); } } @@ -1771,11 +1778,15 @@ static int pp_collect_finished(struct parallel_processes *pp, } else { const size_t n = opts->processes; - strbuf_write(&pp->children[i].err, stderr); + /* Output errors, then all other finished child processes */ + if (opts->consume_sideband) { + opts->consume_sideband(&pp->children[i].err, opts->data); + opts->consume_sideband(&pp->buffered_output, opts->data); + } else { + strbuf_write(&pp->children[i].err, stderr); + strbuf_write(&pp->buffered_output, stderr); + } strbuf_reset(&pp->children[i].err); - - /* Output all other finished child processes */ - strbuf_write(&pp->buffered_output, stderr); strbuf_reset(&pp->buffered_output); /* @@ -1819,10 +1830,10 @@ static void pp_handle_child_IO(struct parallel_processes *pp, } pp_buffer_stderr(pp, opts, output_timeout); - pp_output(pp); + pp_output(pp, opts); } -void run_processes_parallel(const struct run_process_parallel_opts *opts) +void run_processes_parallel(struct run_process_parallel_opts *opts) { int i, code; int output_timeout = 100; @@ -1841,6 +1852,10 @@ void run_processes_parallel(const struct run_process_parallel_opts *opts) "max:%"PRIuMAX, (uintmax_t)opts->processes); + /* ungroup and reading sideband are mutualy exclusive, so disable ungroup */ + if (opts->ungroup && opts->consume_sideband) + opts->ungroup = 0; + /* * Child tasks might receive input via stdin, terminating early (or not), so * ignore the default SIGPIPE which gets handled by each feed_pipe_fn which diff --git a/run-command.h b/run-command.h index 4679987c8e..ad0bab14b0 100644 --- a/run-command.h +++ b/run-command.h @@ -436,6 +436,20 @@ typedef int (*feed_pipe_fn)(int child_in, void *pp_cb, void *pp_task_cb); +/** + * If this callback is provided, instead of collating process output to stderr, + * they will be collated into a new pipe. consume_sideband_fn will be called + * repeatedly. When output is available on that pipe, it will be contained in + * 'output'. But it will be called with an empty 'output' too, to allow for + * keepalives or similar operations if necessary. + * + * pp_cb is the callback cookie as passed into run_processes_parallel. + * + * Since this callback is provided with the collated output, no task cookie is + * provided. + */ +typedef void (*consume_sideband_fn)(struct strbuf *output, void *pp_cb); + /** * This callback is called on every child process that finished processing. * @@ -495,6 +509,12 @@ struct run_process_parallel_opts */ feed_pipe_fn feed_pipe; + /* + * consume_sideband: see consume_sideband_fn() above. This can be NULL + * to omit any special handling. + */ + consume_sideband_fn consume_sideband; + /** * task_finished: See task_finished_fn() above. This can be * NULL to omit any special handling. @@ -529,7 +549,7 @@ struct run_process_parallel_opts * emitting their own output, including dealing with any race * conditions due to writing in parallel to stdout and stderr. */ -void run_processes_parallel(const struct run_process_parallel_opts *opts); +void run_processes_parallel(struct run_process_parallel_opts *opts); /** * Convenience function which prepares env for a command to be run in a diff --git a/submodule.c b/submodule.c index fff3c75570..8ff4418e41 100644 --- a/submodule.c +++ b/submodule.c @@ -1821,7 +1821,7 @@ int fetch_submodules(struct repository *r, { int i; struct submodule_parallel_fetch spf = SPF_INIT; - const struct run_process_parallel_opts opts = { + struct run_process_parallel_opts opts = { .tr2_category = "submodule", .tr2_label = "parallel/fetch", diff --git a/t/helper/test-run-command.c b/t/helper/test-run-command.c index dfdb03b3ab..95152a0395 100644 --- a/t/helper/test-run-command.c +++ b/t/helper/test-run-command.c @@ -58,6 +58,16 @@ static int no_job(struct child_process *cp UNUSED, return 0; } +static void test_consume_sideband(struct strbuf *output, void *cb UNUSED) +{ + FILE *sideband; + + sideband = fopen("./sideband", "a"); + + strbuf_write(output, sideband); + fclose(sideband); +} + static int task_finished(int result UNUSED, struct strbuf *err, void *pp_cb UNUSED, @@ -198,6 +208,7 @@ static int testsuite(int argc, const char **argv) .get_next_task = next_test, .start_failure = test_failed, .feed_pipe = test_stdin_pipe_feed, + .consume_sideband = test_consume_sideband, .task_finished = test_finished, .data = &suite, }; @@ -514,6 +525,10 @@ int cmd__run_command(int argc, const char **argv) opts.get_next_task = parallel_next; opts.task_finished = task_finished_quiet; opts.feed_pipe = test_stdin_pipe_feed; + } else if (!strcmp(argv[1], "run-command-sideband")) { + opts.get_next_task = parallel_next; + opts.consume_sideband = test_consume_sideband; + opts.task_finished = task_finished_quiet; } else { ret = 1; fprintf(stderr, "check usage\n"); diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh index 282afecefc..38249e4798 100755 --- a/t/t0061-run-command.sh +++ b/t/t0061-run-command.sh @@ -164,6 +164,13 @@ test_expect_success 'run_command runs ungrouped in parallel with more tasks than test_line_count = 4 err ' +test_expect_success 'run_command can divert output' ' + test_when_finished rm sideband && + test-tool run-command run-command-sideband 3 sh -c "printf \"%s\n%s\n\" Hello World" 2>actual && + test_must_be_empty actual && + test_cmp expect sideband +' + cat >expect <<-EOF preloaded output of a child listening for stdin: -- 2.49.1