[PATCH 2/2] trace2: randomize/timestamp trace2 targets
- From
Josh Steadmon <steadmon@google.com>
- Date
- Mar 13, 2019, 23:33 UTC
- Message-ID
- <17ec237ba7498251a3ff64eec259d6f61c8f5ccc.1552519463.git.steadmon@google.com>
- In-Reply-To
- <cover.1552519463.git.steadmon@google.com>
When the value of a trace2 environment variable contains instances of the string "%ISO8601%", expand them into the current UTC timestamp in ISO 8601 format.
When the value of a trace2 environment variable is an absolute path referring to an existing directory, write output to randomly-named files under the given directory. If the value is an absolute path referring to a non-existent file and ends with a dash, use the value as a prefix for randomly named files.
The random filenames will consist of the value of the environment variable (after potential timestamp expansion), followed by a 6 character random string such as would be produced by mkstemp(3).
This makes it more convenient to collect traces for every git invocation by unconditionally setting the relevant trace2 envvar to a constant directory name.
Signed-off-by: Josh Steadmon <steadmon@google.com> --- Documentation/technical/api-trace2.txt | 10 +++ t/t0210-trace2-normal.sh | 93 ++++++++++++++++++++++++++ trace2/tr2_dst.c | 86 +++++++++++++++++++++++- 3 files changed, 187 insertions(+), 2 deletions(-)
diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt index 2de565fa3d..1362bf7d0b 100644 --- a/Documentation/technical/api-trace2.txt +++ b/Documentation/technical/api-trace2.txt @@ -109,6 +109,16 @@ values are recognized. Enables the target, opens and writes to the file in append mode. + If the path includes any instances of the string "%ISO8601%", they will + be replaced with the current UTC timestamp in ISO 8601 format with + dashes and colons removed, e.g., "20190315T143059Z". + + If (after potential timestamp expansion) the path already exists and is + a directory, the traces will write to randomly-named files (one per + process) under the given directory. If the pathname does not already + exist and ends with a dash, it will be used as a prefix for + randomly-named files (one per process). + `af_unix:[<socket_type>:]<absolute-pathname>`:: Enables the target, opens and writes to a Unix Domain Socket diff --git a/t/t0210-trace2-normal.sh b/t/t0210-trace2-normal.sh index 03a0aedb1d..1b992c3e61 100755 --- a/t/t0210-trace2-normal.sh +++ b/t/t0210-trace2-normal.sh @@ -80,6 +80,99 @@ test_expect_success 'normal stream, return code 1' ' test_cmp expect actual ' +test_expect_success 'randomized filename' ' + test_when_finished "rm -r traces actual expect" && + mkdir traces && + GIT_TR2="$(pwd)/traces" test-tool trace2 001return 0 && + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <"$(ls traces/??????)" >actual && + cat >expect <<-EOF && + version $V + start _EXE_ trace2 001return 0 + cmd_name trace2 (trace2) + exit elapsed:_TIME_ code:0 + atexit elapsed:_TIME_ code:0 + EOF + test_cmp expect actual +' + +test_expect_success 'randomized filename with prefix' ' + test_when_finished "rm -r traces actual expect" && + mkdir traces && + GIT_TR2="$(pwd)/traces/trace-" test-tool trace2 001return 0 && + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <"$(ls traces/trace-??????)" >actual && + cat >expect <<-EOF && + version $V + start _EXE_ trace2 001return 0 + cmd_name trace2 (trace2) + exit elapsed:_TIME_ code:0 + atexit elapsed:_TIME_ code:0 + EOF + test_cmp expect actual +' + +test_expect_success 'timestamped filename' ' + test_when_finished "rm -r traces actual expect" && + mkdir traces && + GIT_TEST_DATE_NOW=1552658399 GIT_TR2="$(pwd)/traces/trace.%ISO8601%" \ + test-tool trace2 001return 0 && + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <traces/trace.20190315T135959Z >actual && + cat >expect <<-EOF && + version $V + start _EXE_ trace2 001return 0 + cmd_name trace2 (trace2) + exit elapsed:_TIME_ code:0 + atexit elapsed:_TIME_ code:0 + EOF + test_cmp expect actual +' + +test_expect_success 'multiple timestamps' ' + test_when_finished "rm -r traces actual expect" && + mkdir -p traces/20190315T135959Z && + GIT_TEST_DATE_NOW=1552658399 GIT_TR2="$(pwd)/traces/%ISO8601%/trace.%ISO8601%" \ + test-tool trace2 001return 0 && + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <traces/20190315T135959Z/trace.20190315T135959Z >actual && + cat >expect <<-EOF && + version $V + start _EXE_ trace2 001return 0 + cmd_name trace2 (trace2) + exit elapsed:_TIME_ code:0 + atexit elapsed:_TIME_ code:0 + EOF + test_cmp expect actual +' + +test_expect_success 'timestamp plus randomization' ' + test_when_finished "rm -r traces actual expect" && + mkdir traces && + GIT_TEST_DATE_NOW=1552658399 GIT_TR2="$(pwd)/traces/trace-%ISO8601%-" test-tool trace2 001return 0 && + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <"$(ls traces/trace-20190315T135959Z-??????)" >actual && + cat >expect <<-EOF && + version $V + start _EXE_ trace2 001return 0 + cmd_name trace2 (trace2) + exit elapsed:_TIME_ code:0 + atexit elapsed:_TIME_ code:0 + EOF + test_cmp expect actual +' +test_expect_success 'no randomization if target exists' ' + test_when_finished "rm -r traces actual expect" && + mkdir traces && + touch traces/trace- && + GIT_TR2="$(pwd)/traces/trace-" test-tool trace2 001return 0 && + perl "$TEST_DIRECTORY/t0210/scrub_normal.perl" <traces/trace- >actual && + cat >expect <<-EOF && + version $V + start _EXE_ trace2 001return 0 + cmd_name trace2 (trace2) + exit elapsed:_TIME_ code:0 + atexit elapsed:_TIME_ code:0 + EOF + test_cmp expect actual +' + + # Verb 002exit # # Explicit exit(code) from within cmd_<verb> propagates <code>. diff --git a/trace2/tr2_dst.c b/trace2/tr2_dst.c index fd490a43ad..27405a92b4 100644 --- a/trace2/tr2_dst.c +++ b/trace2/tr2_dst.c @@ -12,6 +12,11 @@ */ #define TR2_ENVVAR_DST_DEBUG "GIT_TR2_DST_DEBUG" +/* Constant string used for timestamp replacement in output destination + * filenames. See tr2_replace_timestamp_templates() below. + */ +static const char *iso_timestamp_tmpl = "%ISO8601%"; + static int tr2_dst_want_warning(void) { static int tr2env_dst_debug = -1; @@ -55,6 +60,64 @@ static int tr2_dst_try_path(struct tr2_dst *dst, const char *tgt_value) return dst->fd; } +static void tr2_replace_timestamp_templates(const char *path, + struct strbuf *modified_path) +{ + char *iso_ptr; + + strbuf_addstr(modified_path, path); + + iso_ptr = strstr(modified_path->buf, iso_timestamp_tmpl); + if (iso_ptr) { + struct timeval tv; + struct tm tm; + size_t iso_len = strlen(iso_timestamp_tmpl); + struct strbuf timestamp = STRBUF_INIT; + + get_time(&tv); + gmtime_r(&tv.tv_sec, &tm); + strbuf_addftime(×tamp, "%Y%m%dT%H%M%SZ", &tm, 0, 0); + + while (iso_ptr) { + strbuf_splice(modified_path, + iso_ptr - modified_path->buf, iso_len, + timestamp.buf, timestamp.len); + + iso_ptr = strstr(modified_path->buf, + iso_timestamp_tmpl); + } + + strbuf_release(×tamp); + } +} + +static int tr2_dst_try_random_path(struct tr2_dst *dst, struct strbuf *path) +{ + int fd; + char last_path_char; + + last_path_char = path->buf[path->len - 1]; + if (!is_dir_sep(last_path_char) && last_path_char != '-') + strbuf_addch(path, '/'); + + strbuf_addstr(path, "XXXXXX"); + + fd = mkstemp(path->buf); + if (fd == -1) { + if (tr2_dst_want_warning()) + warning("trace2: could not open '%s' for '%s' tracing: %s", + path->buf, dst->env_var_name, strerror(errno)); + tr2_dst_trace_disable(dst); + return 0; + } + + dst->fd = fd; + dst->need_close = 1; + dst->initialized = 1; + + return dst->fd; +} + #ifndef NO_UNIX_SOCKETS #define PREFIX_AF_UNIX "af_unix:" #define PREFIX_AF_UNIX_STREAM "af_unix:stream:" @@ -177,6 +240,7 @@ static void tr2_dst_malformed_warning(struct tr2_dst *dst, int tr2_dst_get_trace_fd(struct tr2_dst *dst) { const char *tgt_value; + struct stat st; /* don't open twice */ if (dst->initialized) @@ -202,8 +266,26 @@ int tr2_dst_get_trace_fd(struct tr2_dst *dst) return dst->fd; } - if (is_absolute_path(tgt_value)) - return tr2_dst_try_path(dst, tgt_value); + if (is_absolute_path(tgt_value)) { + int fd; + struct strbuf modified_path = STRBUF_INIT; + + tr2_replace_timestamp_templates(tgt_value, &modified_path); + + /* + * Randomize the path if it is an existing directory, or if the + * path does not exist and ends with '-'. + */ + if (is_directory(modified_path.buf) || + (stat(modified_path.buf, &st) == -1 && errno == ENOENT && + modified_path.buf[modified_path.len - 1] == '-')) + fd = tr2_dst_try_random_path(dst, &modified_path); + else + fd = tr2_dst_try_path(dst, modified_path.buf); + + strbuf_release(&modified_path); + return fd; + } #ifndef NO_UNIX_SOCKETS if (starts_with(tgt_value, PREFIX_AF_UNIX))
-- 2.21.0.360.g471c308f928-goog