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git/trace2.h

534 lines
19 KiB

#ifndef TRACE2_H
#define TRACE2_H
/**
* The Trace2 API can be used to print debug, performance, and telemetry
* information to stderr or a file. The Trace2 feature is inactive unless
* explicitly enabled by enabling one or more Trace2 Targets.
*
* The Trace2 API is intended to replace the existing (Trace1)
* printf-style tracing provided by the existing `GIT_TRACE` and
* `GIT_TRACE_PERFORMANCE` facilities. During initial implementation,
* Trace2 and Trace1 may operate in parallel.
*
* The Trace2 API defines a set of high-level messages with known fields,
* such as (`start`: `argv`) and (`exit`: {`exit-code`, `elapsed-time`}).
*
* Trace2 instrumentation throughout the Git code base sends Trace2
* messages to the enabled Trace2 Targets. Targets transform these
* messages content into purpose-specific formats and write events to
* their data streams. In this manner, the Trace2 API can drive
* many different types of analysis.
*
* Targets are defined using a VTable allowing easy extension to other
* formats in the future. This might be used to define a binary format,
* for example.
*
* Trace2 is controlled using `trace2.*` config values in the system and
* global config files and `GIT_TRACE2*` environment variables. Trace2 does
* not read from repo local or worktree config files or respect `-c`
* command line config settings.
*
* For more info about: trace2 targets, conventions for public functions and
* macros, trace2 target formats and examples on trace2 API usage refer to
* Documentation/technical/api-trace2.txt
*
*/
struct child_process;
struct repository;
struct json_writer;
/*
* The public TRACE2 routines are grouped into the following groups:
*
* [] trace2_initialize -- initialization.
* [] trace2_cmd_* -- emit command/control messages.
* [] trace2_child* -- emit child start/stop messages.
* [] trace2_exec* -- emit exec start/stop messages.
* [] trace2_thread* -- emit thread start/stop messages.
* [] trace2_def* -- emit definition/parameter mesasges.
* [] trace2_region* -- emit region nesting messages.
* [] trace2_data* -- emit region/thread/repo data messages.
* [] trace2_printf* -- legacy trace[1] messages.
*/
/*
* Initialize the TRACE2 clock and do nothing else, in particular
* no mallocs, no system inspection, and no environment inspection.
*
* This should be called at the very top of main() to capture the
* process start time. This is intended to reduce chicken-n-egg
* bootstrap pressure.
*
* It is safe to call this more than once. This allows capturing
* absolute startup costs on Windows which uses a little trickery
* to do setup work before common-main.c:main() is called.
*
* The main trace2_initialize_fl() may be called a little later
* after more infrastructure is established.
*/
void trace2_initialize_clock(void);
/*
* Initialize TRACE2 tracing facility if any of the builtin TRACE2
* targets are enabled in the system config or the environment.
* This includes setting up the Trace2 thread local storage (TLS).
* Emits a 'version' message containing the version of git
* and the Trace2 protocol.
*
* This function should be called from `main()` as early as possible in
* the life of the process after essential process initialization.
*
* Cleanup/Termination is handled automatically by a registered
* atexit() routine.
*/
void trace2_initialize_fl(const char *file, int line);
#define trace2_initialize() trace2_initialize_fl(__FILE__, __LINE__)
/*
* Return 1 if trace2 is enabled (at least one target is active).
*/
int trace2_is_enabled(void);
/*
* Emit a 'start' event with the original (unmodified) argv.
*/
void trace2_cmd_start_fl(const char *file, int line, const char **argv);
#define trace2_cmd_start(argv) trace2_cmd_start_fl(__FILE__, __LINE__, (argv))
/*
* Emit an 'exit' event.
*
* Write the exit-code that will be passed to exit() or returned
* from main().
*
* Use this prior to actually calling exit().
* See "#define exit()" in git-compat-util.h
*/
int trace2_cmd_exit_fl(const char *file, int line, int code);
#define trace2_cmd_exit(code) (trace2_cmd_exit_fl(__FILE__, __LINE__, (code)))
/*
* Emit an 'error' event.
*
* Write an error message to the TRACE2 targets.
*/
void trace2_cmd_error_va_fl(const char *file, int line, const char *fmt,
va_list ap);
#define trace2_cmd_error_va(fmt, ap) \
trace2_cmd_error_va_fl(__FILE__, __LINE__, (fmt), (ap))
/*
* Emit a 'pathname' event with the canonical pathname of the current process
* This gives post-processors a simple field to identify the command without
* having to parse the argv. For example, to distinguish invocations from
* installed versus debug executables.
*/
void trace2_cmd_path_fl(const char *file, int line, const char *pathname);
#define trace2_cmd_path(p) trace2_cmd_path_fl(__FILE__, __LINE__, (p))
/*
* Emit an 'ancestry' event with the process name of the current process's
* parent process.
* This gives post-processors a way to determine what invoked the command and
* learn more about usage patterns.
*/
void trace2_cmd_ancestry_fl(const char *file, int line, const char **parent_names);
#define trace2_cmd_ancestry(v) trace2_cmd_ancestry_fl(__FILE__, __LINE__, (v))
/*
* Emit a 'cmd_name' event with the canonical name of the command.
* This gives post-processors a simple field to identify the command
* without having to parse the argv.
*/
void trace2_cmd_name_fl(const char *file, int line, const char *name);
#define trace2_cmd_name(v) trace2_cmd_name_fl(__FILE__, __LINE__, (v))
/*
* Emit a 'cmd_mode' event to further describe the command being run.
* For example, "checkout" can checkout a single file or can checkout a
* different branch. This gives post-processors a simple field to compare
* equivalent commands without having to parse the argv.
*/
void trace2_cmd_mode_fl(const char *file, int line, const char *mode);
#define trace2_cmd_mode(sv) trace2_cmd_mode_fl(__FILE__, __LINE__, (sv))
/*
* Emits an "alias" message containing the alias used and the argument
* expansion.
*/
void trace2_cmd_alias_fl(const char *file, int line, const char *alias,
const char **argv);
#define trace2_cmd_alias(alias, argv) \
trace2_cmd_alias_fl(__FILE__, __LINE__, (alias), (argv))
/*
* Emit one or more 'def_param' events for "important" configuration
* settings.
*
* Use the TR2_SYSENV_CFG_PARAM setting to register a comma-separated
* list of patterns configured important. For example:
* git config --system trace2.configParams 'core.*,remote.*.url'
* or:
* GIT_TRACE2_CONFIG_PARAMS=core.*,remote.*.url"
*
* Note: this routine does a read-only iteration on the config data
* (using read_early_config()), so it must not be called until enough
* of the process environment has been established. This includes the
* location of the git and worktree directories, expansion of any "-c"
* and "-C" command line options, and etc.
*/
void trace2_cmd_list_config_fl(const char *file, int line);
#define trace2_cmd_list_config() trace2_cmd_list_config_fl(__FILE__, __LINE__)
/*
* Emit one or more 'def_param' events for "important" environment variables.
*
* Use the TR2_SYSENV_ENV_VARS setting to register a comma-separated list of
* environment variables considered important. For example:
* git config --system trace2.envVars 'GIT_HTTP_USER_AGENT,GIT_CONFIG'
* or:
* GIT_TRACE2_ENV_VARS="GIT_HTTP_USER_AGENT,GIT_CONFIG"
*/
void trace2_cmd_list_env_vars_fl(const char *file, int line);
#define trace2_cmd_list_env_vars() trace2_cmd_list_env_vars_fl(__FILE__, __LINE__)
/*
* Emit a "def_param" event for the given config key/value pair IF
* we consider the key to be "important".
*
* Use this for new/updated config settings created/updated after
* trace2_cmd_list_config() is called.
*/
void trace2_cmd_set_config_fl(const char *file, int line, const char *key,
const char *value);
#define trace2_cmd_set_config(k, v) \
trace2_cmd_set_config_fl(__FILE__, __LINE__, (k), (v))
/**
* Emits a "child_start" message containing the "child-id",
* "child-argv", and "child-classification".
*
* Before calling optionally set "cmd->trace2_child_class" to a string
* describing the type of the child process. For example, "editor" or
* "pager".
*
* This function assigns a unique "child-id" to `cmd->trace2_child_id`.
* This field is used later during the "child_exit" message to associate
* it with the "child_start" message.
*
* This function should be called before spawning the child process.
*/
void trace2_child_start_fl(const char *file, int line,
struct child_process *cmd);
#define trace2_child_start(cmd) trace2_child_start_fl(__FILE__, __LINE__, (cmd))
/**
* Emits a "child_exit" message containing the "child-id",
* the child's elapsed time and exit-code.
*
* The reported elapsed time includes the process creation overhead and
* time spend waiting for it to exit, so it may be slightly longer than
* the time reported by the child itself.
*
* This function should be called after reaping the child process.
*/
void trace2_child_exit_fl(const char *file, int line, struct child_process *cmd,
int child_exit_code);
#define trace2_child_exit(cmd, code) \
trace2_child_exit_fl(__FILE__, __LINE__, (cmd), (code))
/**
* Emits a "child_ready" message containing the "child-id" and a flag
* indicating whether the child was considered "ready" when we
* released it.
*
* This function should be called after starting a daemon process in
* the background (and after giving it sufficient time to boot
* up) to indicate that we no longer control or own it.
*
* The "ready" argument should contain one of { "ready", "timeout",
* "error" } to indicate the state of the running daemon when we
* released it.
*
* If the daemon process fails to start or it exits or is terminated
* while we are still waiting for it, the caller should emit a
* regular "child_exit" to report the normal process exit information.
*
*/
void trace2_child_ready_fl(const char *file, int line,
struct child_process *cmd,
const char *ready);
#define trace2_child_ready(cmd, ready) \
trace2_child_ready_fl(__FILE__, __LINE__, (cmd), (ready))
/**
* Emit an 'exec' event prior to calling one of exec(), execv(),
* execvp(), and etc. On Unix-derived systems, this will be the
* last event emitted for the current process, unless the exec
* fails. On Windows, exec() behaves like 'child_start' and a
* waitpid(), so additional events may be emitted.
*
* Returns a unique "exec-id". This value is used later
* if the exec() fails and a "exec-result" message is necessary.
*/
int trace2_exec_fl(const char *file, int line, const char *exe,
const char **argv);
#define trace2_exec(exe, argv) trace2_exec_fl(__FILE__, __LINE__, (exe), (argv))
/**
* Emit an 'exec_result' when possible. On Unix-derived systems,
* this should be called after exec() returns (which only happens
* when there is an error starting the new process). On Windows,
* this should be called after the waitpid().
*
* The "exec_id" should be the value returned from trace2_exec().
*/
void trace2_exec_result_fl(const char *file, int line, int exec_id, int code);
#define trace2_exec_result(id, code) \
trace2_exec_result_fl(__FILE__, __LINE__, (id), (code))
/*
* Emit a 'thread_start' event. This must be called from inside the
* thread-proc to set up the trace2 TLS data for the thread.
*
* Thread names should be descriptive, like "preload_index".
* Thread names will be decorated with an instance number automatically.
*/
void trace2_thread_start_fl(const char *file, int line,
const char *thread_name);
#define trace2_thread_start(thread_name) \
trace2_thread_start_fl(__FILE__, __LINE__, (thread_name))
/*
* Emit a 'thread_exit' event. This must be called from inside the
* thread-proc to report thread-specific data and cleanup TLS data
* for the thread.
*/
void trace2_thread_exit_fl(const char *file, int line);
#define trace2_thread_exit() trace2_thread_exit_fl(__FILE__, __LINE__)
/*
* Emits a "def_param" message containing a key/value pair.
*
* This message is intended to report some global aspect of the current
* command, such as a configuration setting or command line switch that
* significantly affects program performance or behavior, such as
* `core.abbrev`, `status.showUntrackedFiles`, or `--no-ahead-behind`.
*/
void trace2_def_param_fl(const char *file, int line, const char *param,
const char *value);
#define trace2_def_param(param, value) \
trace2_def_param_fl(__FILE__, __LINE__, (param), (value))
/*
* Tell trace2 about a newly instantiated repo object and assign
* a trace2-repo-id to be used in subsequent activity events.
*
* Emits a 'worktree' event for this repo instance.
*
* Region and data messages may refer to this repo-id.
*
* The main/top-level repository will have repo-id value 1 (aka "r1").
*
* The repo-id field is in anticipation of future in-proc submodule
* repositories.
*/
void trace2_def_repo_fl(const char *file, int line, struct repository *repo);
#define trace2_def_repo(repo) trace2_def_repo_fl(__FILE__, __LINE__, repo)
/**
* Emit a 'region_enter' event for <category>.<label> with optional
* repo-id and printf message.
*
* This function pushes a new region nesting stack level on the current
* thread and starts a clock for the new stack frame.
*
* The `category` field is an arbitrary category name used to classify
* regions by feature area, such as "status" or "index". At this time
* it is only just printed along with the rest of the message. It may
* be used in the future to filter messages.
*
* The `label` field is an arbitrary label used to describe the activity
* being started, such as "read_recursive" or "do_read_index".
*
* The `repo` field, if set, will be used to get the "repo-id", so that
* recursive operations can be attributed to the correct repository.
*/
void trace2_region_enter_fl(const char *file, int line, const char *category,
const char *label, const struct repository *repo, ...);
#define trace2_region_enter(category, label, repo) \
trace2_region_enter_fl(__FILE__, __LINE__, (category), (label), (repo))
void trace2_region_enter_printf_va_fl(const char *file, int line,
const char *category, const char *label,
const struct repository *repo,
const char *fmt, va_list ap);
#define trace2_region_enter_printf_va(category, label, repo, fmt, ap) \
trace2_region_enter_printf_va_fl(__FILE__, __LINE__, (category), \
(label), (repo), (fmt), (ap))
void trace2_region_enter_printf_fl(const char *file, int line,
const char *category, const char *label,
const struct repository *repo,
const char *fmt, ...);
#ifdef HAVE_VARIADIC_MACROS
#define trace2_region_enter_printf(category, label, repo, ...) \
trace2_region_enter_printf_fl(__FILE__, __LINE__, (category), (label), \
(repo), __VA_ARGS__)
#else
/* clang-format off */
__attribute__((format (region_enter_printf, 4, 5)))
void trace2_region_enter_printf(const char *category, const char *label,
const struct repository *repo, const char *fmt,
...);
/* clang-format on */
#endif
/**
* Emit a 'region_leave' event for <category>.<label> with optional
* repo-id and printf message.
*
* Leave current nesting level and report the elapsed time spent
* in this nesting level.
*
* The `category`, `label`, and `repo` fields are the same as
* trace2_region_enter_fl. The `category` and `label` do not
* need to match the corresponding "region_enter" message,
* but it makes the data stream easier to understand.
*/
void trace2_region_leave_fl(const char *file, int line, const char *category,
const char *label, const struct repository *repo, ...);
#define trace2_region_leave(category, label, repo) \
trace2_region_leave_fl(__FILE__, __LINE__, (category), (label), (repo))
void trace2_region_leave_printf_va_fl(const char *file, int line,
const char *category, const char *label,
const struct repository *repo,
const char *fmt, va_list ap);
#define trace2_region_leave_printf_va(category, label, repo, fmt, ap) \
trace2_region_leave_printf_va_fl(__FILE__, __LINE__, (category), \
(label), (repo), (fmt), (ap))
void trace2_region_leave_printf_fl(const char *file, int line,
const char *category, const char *label,
const struct repository *repo,
const char *fmt, ...);
#ifdef HAVE_VARIADIC_MACROS
#define trace2_region_leave_printf(category, label, repo, ...) \
trace2_region_leave_printf_fl(__FILE__, __LINE__, (category), (label), \
(repo), __VA_ARGS__)
#else
/* clang-format off */
__attribute__((format (region_leave_printf, 4, 5)))
void trace2_region_leave_printf(const char *category, const char *label,
const struct repository *repo, const char *fmt,
...);
/* clang-format on */
#endif
/**
* Emit a key-value pair 'data' event of the form <category>.<key> = <value>.
* This event implicitly contains information about thread, nesting region,
* and optional repo-id.
* This could be used to print the number of files in a directory during
* a multi-threaded recursive tree walk.
*
* On event-based TRACE2 targets, this generates a 'data' event suitable
* for post-processing. On printf-based TRACE2 targets, this is converted
* into a fixed-format printf message.
*/
void trace2_data_string_fl(const char *file, int line, const char *category,
const struct repository *repo, const char *key,
const char *value);
#define trace2_data_string(category, repo, key, value) \
trace2_data_string_fl(__FILE__, __LINE__, (category), (repo), (key), \
(value))
void trace2_data_intmax_fl(const char *file, int line, const char *category,
const struct repository *repo, const char *key,
intmax_t value);
#define trace2_data_intmax(category, repo, key, value) \
trace2_data_intmax_fl(__FILE__, __LINE__, (category), (repo), (key), \
(value))
void trace2_data_json_fl(const char *file, int line, const char *category,
const struct repository *repo, const char *key,
const struct json_writer *jw);
#define trace2_data_json(category, repo, key, value) \
trace2_data_json_fl(__FILE__, __LINE__, (category), (repo), (key), \
(value))
/*
* Emit a 'printf' event.
*
* Write an arbitrary formatted message to the TRACE2 targets. These
* text messages should be considered as human-readable strings without
* any formatting guidelines. Post-processors may choose to ignore
* them.
*/
void trace2_printf_va_fl(const char *file, int line, const char *fmt,
va_list ap);
#define trace2_printf_va(fmt, ap) \
trace2_printf_va_fl(__FILE__, __LINE__, (fmt), (ap))
void trace2_printf_fl(const char *file, int line, const char *fmt, ...);
#ifdef HAVE_VARIADIC_MACROS
#define trace2_printf(...) trace2_printf_fl(__FILE__, __LINE__, __VA_ARGS__)
#else
/* clang-format off */
__attribute__((format (printf, 1, 2)))
void trace2_printf(const char *fmt, ...);
/* clang-format on */
#endif
/*
* Optional platform-specific code to dump information about the
* current and any parent process(es). This is intended to allow
* post-processors to know who spawned this git instance and anything
* else that the platform may be able to tell us about the current process.
*/
enum trace2_process_info_reason {
TRACE2_PROCESS_INFO_STARTUP,
TRACE2_PROCESS_INFO_EXIT,
};
void trace2_collect_process_info(enum trace2_process_info_reason reason);
const char *trace2_session_id(void);
#endif /* TRACE2_H */