ttb
(observer)A base for building trace tools for distributed systems.
The Trace Tool Builder ttb
is a base for building trace
tools for distributed systems.
When using ttb
, dbg
shall not be used in parallel.
Functions
tracer() -> Result
This is equivalent to tracer(node())
.
tracer(Nodes) -> Result
This is equivalent to tracer(Nodes,[])
.
tracer(Nodes,Opts) -> Result
Result = {ok, ActivatedNodes} | {error,Reason}
Nodes = atom() | [atom()] | all | existing | new
Opts = [Opt]
Opt = {file,Client} | {handler, FormatHandler} | {process_info,PI}
Client = File | {local, File}
File = Filename | Wrap
Filename = string()
Wrap = {wrap,Filename} | {wrap,Filename,Size,Count}
FormatHandler = See format/2
PI = true | false
This function starts a file trace port on all given nodes and also points the system tracer for sequential tracing to the same port.
The given Filename
will be prefixed with the node
name. Default Filename
is "ttb".
File={wrap,Filename,Size,Count}
can be used if
the size of the trace logs must be limited. Default values are
Size=128*1024
and Count=8
.
When tracing diskless nodes, ttb
must be started
from an external "trace control node" with disk access, and
Client
must be {local, File}
. All
trace information is then sent to the trace control node where
it is written to file.
The process_info
option indicates if process
information should be collected. If PI = true
(which is
default), each process identifier Pid
is replaced by a
tuple {Pid,ProcessInfo,Node}
, where ProcessInfo
is the process' registered name its globally registered name,
or its initial function. It is possible to turn off this
functionality by setting PI = false
.
p(Procs,Flags) -> Return
Return = {ok,[{Procs,MatchDesc}]}
Procs = Process | [Process] | all | new | existing
Process = pid() | atom() | {global,atom()}
Flags = Flag | [Flag]
This function sets the given trace flags on the given processes.
Please turn to the Reference manual for module dbg
for details about the possible trace flags. The parameter
MatchDesc
is the same as returned from dbg:p/2
Processes can be given as registered names, globally registered names or process identifiers. If a registered name is given, the flags are set on processes with this name on all active nodes.
These functions should be used in combination with the
call
trace flag for setting and clearing trace
patterns. When the call
trace flag is set on a process,
function calls will be traced on that process if a trace
pattern has been set for the called function. Trace patterns
specifies how to trace a function by using match
specifications. Match specifications are described in the
User's Guide for the erlang runtime system erts
.
These functions are equivalent to the corresponding
functions in dbg
, but all calls are stored in the
history. The history buffer makes it easy to create config
files so that the same trace environment can be setup several
times, e.g. if you want to compare two test runs. It also
reduces the amount of typing when using ttb
from the
erlang shell.
tp
- Set trace pattern on global function calls
tpl
- Set trace pattern on local and global function calls
ctp
- Clear trace pattern on local and global function calls
ctpl
- Clear trace pattern on local function calls
ctpg
- Clear trace pattern on global function calls
list_history() -> History
History = [{N,Func,Args}]
All calls to ttb
is stored in the history. This
function returns the current content of the history. Any entry
can be re-executed with run_history/1
or stored in a
config file with write_config/2/3
.
run_history(N) -> ok | {error, Reason}
N = integer() | [integer()]
Executes the given entry or entries from the history
list. History can be listed with list_history/0
.
write_config(ConfigFile,Config)
Equivalent to write_config(ConfigFile,Config,[])
.
write_config(ConfigFile,Config,Opt) -> ok | {error,Reason}
ConfigFile = string()
Config = all | [integer()] | [{Mod,Func,Args}]
Mod = atom()
Func = atom()
Args = [term()]
Opt = [] | [append]
This function creates or extends a config file which can be used for restoring a specific configuration later.
The content of the config file can either be fetched from
the history or given directly as a list of
{Mod,Func,Args}
.
If the complete history is to be stored in the config file
Config
should be all
. If only a selected number
of entries from the history should be stored, Config
should be a list of integers pointing out the entries to be
stored.
If Opt
is not given or if it is []
,
ConfigFile
is deleted and a new file is created. If
Opt = [append]
, ConfigFile
will not be deleted.
The new information will be appended at the end of the file.
run_config(ConfigFile) -> ok | {error,Reason}
ConfigFile = string()
Executes all entries in the given config file.
run_config(ConfigFile,NumList) -> ok | {error,Reason}
ConfigFile = string()
NumList = [integer()]
Executes selected entries from the given config
file. NumList
is a list of integers pointing out the
entries to be executed.
The content of a config file can be listed with
list_config/1
.
list_config(ConfigFile) -> Config | {error,Reason}
ConfigFile = string()
Config = [{N,Func,Args}]
Lists all entries in the given config file.
write_trace_info(Key,Info) -> ok
Key = term()
Info = Data | fun() -> Data
Data = term()
The .ti
file contains {Key,ValueList}
tuples. This function adds Data
to the ValueList
associated with Key
. All information written with this
function will be included in the call to the format handler.
seq_trigger_ms() -> MatchSpec
Equivalent to seq_trigger_ms(all)
seq_trigger_ms(Flags) -> MatchSpec
MatchSpec = match_spec()
Flags = all | SeqTraceFlag | [SeqTraceFlag]
SeqTraceFlag = atom()
A match specification can turn on or off sequential
tracing. This function returns a match specification which
turns on sequential tracing with the given Flags
.
This match specification can be given as the last argument
to tp
or tpl
. The activated Item
will
then become a trigger for sequential tracing. This
means that if the item is called on a process with the
call
trace flag set, the process will be "contaminated"
with the seq_trace token.
If Flags = all
, all possible flags are set.
Please turn to the reference manual for the
seq_trace
module in the kernel
application to see the possible values for
SeqTraceFlag
. For a description of the match_spec()
syntax, please turn to the User's guide for the
runtime system (erts). The chapter Match Specification in Erlang explains the general match
specification "language".
Note!
The system tracer for sequential tracing is
automatically initiated by ttb
when a trace port is
started with ttb:tracer/0/1/2
.
Example of how to use the seq_trigger_ms/0/1
function:
(tiger@durin)5> ttb:tracer(). {ok,[tiger@durin]} (tiger@durin)6> ttb:p(all,call). {ok,{[all],[call]}} (tiger@durin)7> ttb:tp(mod,func,ttb:seq_trigger_ms()). {ok,[{matched,1},{saved,1}]} (tiger@durin)8>
Whenever mod:func(...)
is called after this, the
seq_trace token will be set on the executing process.
stop()
Equivalent to stop([])
.
stop(Opts) -> stopped
Opts = [Opt]
Opt = fetch | format
Stops tracing on all nodes.
The fetch
option indicates that trace logs shall be
collected from all nodes after tracing is stopped. This option
is useful if nodes on remote machines are traced. Logs and
trace information files are then sent to the trace control
node and stored in a directory named
ttb_upload-Timestamp
, where Timestamp
is on the
form yyyymmdd-hhmmss
. Even logs from nodes on the same
machine as the trace control node are moved to this directory.
The format
option indicates that the trace logs
shall be formatted after tracing is stopped. Note that this
option also implies the fetch
option, i.e. logs are
collected in a new directory on the trace control node before
formatting. All logs in the directory will be merged.
format(File)
Same as format(File,[])
.
format(File,Options) -> ok | {error, Reason}
File = string() | [string()]
Options = [Opt]
Opt = {out,Out} | {handler,FormatHandler}
Out = standard_io | string()
FormatHandler = {Function, InitialState} | et
Function = fun(Fd,Trace,TraceInfo,State) -> State
Fd = standard_io | FileDescriptor
Trace = tuple()
TraceInfo = [{Key,ValueList}]
Out
erlang
module for details.flags
, client
and node
, and if handler
is given as option to the tracer function, this is also included. In addition all information written with the write_trace_info/2
function is included. Reads the given binary trace log(s). If a directory or a
list of logs is given and the timestamp
flag was set
during tracing, the trace messages from the different logs are
merged according to the timestamps.
If FormatHandler = {Function,InitialState}
,
Function
will be called for each trace message. If
FormatHandler = et
, et_viewer
in the Event Tracer application (et
) is used for presenting the
trace log graphically. ttb
provides a few different
filters which can be selected from the Filter menu in the
et_viewer
. If FormatHandler
is not given, a
default handler is used which presents each trace message as a
line of text.
If Out
is given, FormatHandler
gets the
filedescriptor to Out
as the first parameter.
Out
is ignored if FormatHandler = et
.
Wrap logs can be formatted one by one or all in one go. To
format one of the wrap logs in a set, give the exact name of
the file. To format the whole set of wrap logs, give the name
with '*' instead of the wrap count. See examples in the
ttb
User's Guide.