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DELAY stage v1.0
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Pipelines v1.9
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>>__ _DELAY__ _________________________________________________________________________><
|_WAKEUP_|
Input record format:
|_ _hh_ ___________________ __________________________________ _ __________ ____________|
| | (1) | | |_argument_|
| |____:mm_ ________ _| |
| | (1) | |
| |____:ss_| |
| _WAIT___ (1) |
|_|________|_+_ _ ___________________________ ____seconds_ _|
|_NOWAIT_| | | (1) | |
| |_ ___________ ____minutes:_| |
| | (1) | |
| |____hours:_| |
| (1) (1) |
|____milliseconds____MS____________________|
Notes:
(1) Spaces are not allowed here.
Use
the DELAY stage to read a record from its primary input stream, wait for some
event to occur, and then copy that record to its primary output stream. DELAY
repeats this process for every input record, processing them one at a time. The
events for which DELAY waits are time-based. DELAY can be told to wait for a
particular time of day or for some time interval to elapse.
When
an input record specifies an actual time of day to wait for:
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DELAY reads a record from its primary input stream and interprets the
first blank delimited word of that record as a time of day to wait for. DELAY
uses this definition on a record by record basis to determine the specified
time to elapse. Each input record can specify a different specification. Each
input record may also specify data after the control definition and this is
considered as the stage command argument. Although DELAY looks at only the
first blank-delimited word when determining the amount of time to wait; it
copies only the input record stage command argument data to its primary
output stream.
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When
an input record specifies a time interval to wait to expire:
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DELAY reads a record from its primary input stream and interprets the
first (up to three) blank delimited words of that record as a WAIT/NOWAIT
operand and an interval definition, respectively. DELAY uses these
definitions on a record by record basis to determine whether to process the
record immediately or to wait for the specified time to elapse, before
writing an output record. Each input record can specify a different
specification. Input records may also specify data after the control
definitions and this is considered as the stage command argument. Although
DELAY looks at only the first three blank-delimited words when determining
the amount of time to wait; it copies only the input record stage command
argument data to its primary output stream.
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hh
is an unsigned
integer which specifies the number of hours.
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:mm
is an unsigned integer which specifies the number
of minutes.
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:ss
is an unsigned integer which specifies the
number of seconds.
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WAIT
specifies
that DELAY should read an input record, wait for the time interval to elapse,
process that record and then write an output record.
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NOWAIT
specifies
that DELAY should read an input record; process that record and write an
output record immediately, then wait for the time interval to elapse.
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+
Indicates
that the following time or millisecond delay value is relative to the current
time.
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hours
is an unsigned integer which specifies the
number of hours to wait.
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minutes:
is an unsigned integer which specifies the
number minutes.
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seconds:
is an unsigned integer which specifies
the number of seconds.
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milliseconds
is an unsigned integer which specifies the number
of milliseconds.
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argument
is the data that
will be written as an output record.
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The following streams are used by the DELAY stage:
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Stream
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Action
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Primary input
stream
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DELAY reads records from its primary input
stream.
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Primary output
stream
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DELAY writes primary input stream records
to its primary output stream.
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1)
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Delay does not delay the records.
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2)
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If the DELAY stage discovers
that its primary output stream is not connected; the DELAY stage ends.
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3)
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The maximum amount of time that the DELAY stage will
wait is: 1209600000 milliseconds (approximately 2 weeks). Windows is
not a real-time system, it is a multi-user/time-share
operating
system which must service its load by priority. As such, this maximum value
may fluctuate by as much as (best estimate) ~20 milliseconds on a machine
even with a light load. The actual start time is dependent on exactly when
the stage is dispatched, the length of time needed to parse its stage command
argument and the length of time needed to enter its runtime phase, before the
clock ‘starts ticking’. If you specify a value which represents a delay value
of less than (or there about) 20 milliseconds; you should not rely on
accuracy. Although, in saying that, since you cannot anticipate the load on
your system, all values must be considered as best case and can never be
relied upon, anywhere near close to ‘exact’.
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4)
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DELAY verifies
that its secondary input and output streams are not connected and then begins
execution.
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The following
pipeline; pings the address: www.tenfiftytwo.co.uk
after every 3 seconds, 5 times. The output generated by the SHELL stage, which
executes the command; is displayed on the console and is also written to the
output file: ping.log.
pipe literal '+3 ping
www.tenfiftytwo.co.uk'
| duplicate 4
| delay
| shell
| console
| > ping.log
None.