Github user trixpan commented on a diff in the pull request:
https://github.com/apache/nifi/pull/980#discussion_r78770355
--- Diff:
nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/TailFile.java
---
@@ -117,31 +173,78 @@
.allowableValues(LOCATION_LOCAL, LOCATION_REMOTE)
.defaultValue(LOCATION_LOCAL.getValue())
.build();
+
static final PropertyDescriptor START_POSITION = new
PropertyDescriptor.Builder()
.name("Initial Start Position")
- .description("When the Processor first begins to tail data,
this property specifies where the Processor should begin reading data. Once
data has been ingested from the file, "
+ .description("When the Processor first begins to tail data,
this property specifies where the Processor should begin reading data. Once
data has been ingested from a file, "
+ "the Processor will continue from the last point
from which it has received data.")
.allowableValues(START_BEGINNING_OF_TIME, START_CURRENT_FILE,
START_CURRENT_TIME)
.defaultValue(START_CURRENT_FILE.getValue())
.required(true)
.build();
+ static final PropertyDescriptor RECURSIVE = new
PropertyDescriptor.Builder()
+ .name("tailfile-recursive-lookup")
+ .displayName("Recursive lookup")
+ .description("When using Multiple files mode, this property
defines if files must be listed recursively or not"
+ + " in the base directory.")
+ .allowableValues("true", "false")
+ .defaultValue("true")
+ .required(true)
+ .build();
+
+ static final PropertyDescriptor ROLLING_STRATEGY = new
PropertyDescriptor.Builder()
+ .name("tailfile-rolling-strategy")
+ .displayName("Rolling Strategy")
+ .description("Specifies if the files to tail have a fixed name
or not.")
+ .required(true)
+ .allowableValues(FIXED_NAME, CHANGING_NAME)
+ .defaultValue(FIXED_NAME.getValue())
+ .build();
+
+ static final PropertyDescriptor LOOKUP_FREQUENCY = new
PropertyDescriptor.Builder()
+ .name("tailfile-lookup-frequency")
+ .displayName("Lookup frequency")
+ .description("Only used in Multiple files mode and Changing
name rolling strategy, it specifies the minimum "
+ + "duration the processor will wait before listing
again the files to tail.")
+ .required(false)
+ .addValidator(StandardValidators.TIME_PERIOD_VALIDATOR)
+ .defaultValue("10 minutes")
--- End diff --
@joewitt
I think @pvillard31 has a point when he says the status of a file should
ALWAYS be tracked unless:
1. overwritten / reset by the user (causing data duplication).
2. too old to be relevant (removed automatically)
Under this arrangement, the two timers make sense:
1 - Maximum age of file - if file is older than this date it won't be
tailed. (_this happens to be very similar to Heka's approach as well_)
2 - How frequently to harvest for new files - self explanatory
2b - if new file is found tail. If file is pre-existent and is older than
max age remove status;
In addition, we could consider what flume-ng taildir called an idle
timeout,
`idleTimeout - Time (ms) to close inactive files. If the closed file is
appended new lines to, this source will automatically re-open it.`
These are files that are younger than maximum age, but largely stagnated.
We would keep their status (until expiry) but they would be closed and only
re-opened if the file size increased (or other tail conditions were be
triggered).
flume-ng tried to deal with resource waste by using and increasing delay to
poll the idle files. The higher the number of polls without new data, the
longer it would take before a new retry. Not sure if this is something we would
like to do but would also help.
Inevitably, most teams using date based naming conventions do that to
prevent performing truncation of a file when logrotate runs and I suspect we
should simply let the user know that having too many files in the same folder,
matching the same URL would cause impact to performance and that compressing
them so they don't match the file regex, or moving them to other directories in
order to minimise resource waste.
Hope this makes sense
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