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another rewrite of the file node type

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Steffen Vogel 2015-08-21 11:35:07 +02:00
parent a5a23ab3ae
commit b42f1ca2ed
2 changed files with 58 additions and 15 deletions
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43
documentation/clients/File.md
View file

@ -1,17 +1,17 @@
# File {#file}
The `file` node-type can be used to log or replay sample values to disk.
The `file` node-type can be used to log or replay samples to / from disk.
## Configuration
Every `file` node supports the following settings:
#### `in`
#### `in` *(string: filesystem path)*
Specifies the path to a file which contains data for replaying.
See below for a description of the file format.
#### `out`
#### `out` *(string: filesystem path)*
Specifies the path to a file where samples will be written to.
This setting allows to add special paceholders for time and date values.
@ -23,13 +23,15 @@ See [strftime(3)](http://man7.org/linux/man-pages/man3/strftime.3.html) for a li
will create a file called: *path_of_working_directory*/logs/measurements_2015-08-09_22-20-50.log
#### `file_mode`
See below for a description of the file format.
#### `file_mode` *(string)*
Specifies the mode which should be used to open the output file.
See [open(2)](http://man7.org/linux/man-pages/man2/open.2.html) for an explanation of allowed values.
The default value is `w+` which will start writing at the beginning of the file and create it in case it does not exist yet.
#### `epoch_mode`
#### `epoch_mode` *("now"|"relative"|"absolute")*
This setting allows to select the behaviour of the following `epoch` setting.
It can be used to adjust the point in time when the first value should be read.
@ -40,13 +42,38 @@ The behaviour of `epoch` is depending on the value of `epoch_mode`.
- `epoch_mode = relative`: The first value is read at *start* + `epoch` seconds.
- `epoch_mode = absolute`: The first value is read at `epoch` seconds after 1970-01-01 00:00:00.
#### `rate`
#### `send_rate` *(float)*
By default `rate` has the value `0`. If the value is non-zero,
By default `send_rate` has the value `0` which means that the time between consecutive samples is the same as in the `in` file based on the timestamps in the first column.
If this setting has a non-zero value, the default behaviour is overwritten with a fixed rate.
### Example
@todo Add extract of example.conf
file_node = {
type = "file",
### The following settings are specific to the file node-type!! ###
mode = "w+", # The mode in which files should be opened (see open(2))
# You might want to use "a+" to append to a file
in = "logs/file_input.log", # These options specify the path prefix where the the files are stored
out = "logs/file_output_%F_%T.log" # The output path accepts all format tokens of (see strftime(3))
epoch_mode = "now" # One of:
# now (default)
# relative
# absolute
epoch = 10 # The interpretation of this value depends on epoch_mode (default is 0):
# - epoch_mode = now: The first value is read at: _now_ + epoch seconds.
# - epoch_mode = relative: The first value is read at _start_ + `epoch` seconds.
# - epoch_mode = absolute: The first value is read at epoch seconds after 1970-01-01 00:00:00.
rate = 2.0 # A constant rate at which the lines of the input files should be read
# A missing or zero value will use the timestamp in the first column
# of the file to determine the pause between consecutive lines.
}
## File Format

30
server/src/file.c
View file

@ -54,10 +54,10 @@ int file_parse(config_setting_t *cfg, struct node *n)
if (config_setting_lookup_string(cfg, "in", &in))
f->path_in = strdup(in);
if (!config_setting_lookup_string(cfg, "mode", &f->file_mode))
if (!config_setting_lookup_string(cfg, "file_mode", &f->file_mode))
f->file_mode = "w+";
if (!config_setting_lookup_float(cfg, "rate", &f->rate))
if (!config_setting_lookup_float(cfg, "send_rate", &f->rate))
f->rate = 0; /* Disable fixed rate sending. Using timestamps of file instead */
if (config_setting_lookup_float(n->cfg, "epoch", &epoch_flt))
@ -170,14 +170,30 @@ int file_read(struct node *n, struct msg *pool, int poolsize, int first, int cnt
if (f->in) {
for (i = 0; i < cnt; i++) {
struct msg *cur = &pool[(first+i) % poolsize];
msg_fscan(f->in, cur);
if (f->rate) {
if (timerfd_wait(f->tfd) < 0)
serror("Failed to wait for timer");
/* Wait until epoch for the first time only */
if (ftell(f->in) == 0) {
struct timespec until = time_add(&f->start, &f->offset);
if (timerfd_wait_until(f->tfd, &until))
serror("Failed to wait for timer");
}
/* Wait with fixed rate delay */
else {
if (timerfd_wait(f->tfd) < 0)
serror("Failed to wait for timer");
}
msg_fscan(f->in, cur);
}
else {
struct timespec until = time_add(&MSG_TS(cur), &f->offset);
struct timespec until;
/* Get message and timestamp */
msg_fscan(f->in, cur);
/* Wait for next message / sampe */
until = time_add(&MSG_TS(cur), &f->offset);
if (timerfd_wait_until(f->tfd, &until) < 0)
serror("Failed to wait for timer");
}