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Merged
merged 3 commits into from
Aug 20, 2018
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Watcher: Properly find next valid date in cron expressions #32734

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78f221b
Watcher: Properly find next valid date in cron expressions
spinscale Aug 9, 2018
6e776bf
Merge branch 'master' into 1808-fix-cron-expression-next-valid-date
spinscale Aug 16, 2018
9deb34f
review comment add expired entry to test
spinscale Aug 16, 2018
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21 changes: 12 additions & 9 deletions ...her/src/main/java/org/elasticsearch/xpack/watcher/trigger/schedule/CronnableSchedule.java
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Original file line number Diff line number Diff line change
Expand Up @@ -13,20 +13,15 @@

public abstract class CronnableSchedule implements Schedule {

private static final Comparator<Cron> CRON_COMPARATOR = new Comparator<Cron>() {
@Override
public int compare(Cron c1, Cron c2) {
return c1.expression().compareTo(c2.expression());
}
};
private static final Comparator<Cron> CRON_COMPARATOR = Comparator.comparing(Cron::expression);

protected final Cron[] crons;

public CronnableSchedule(String... expressions) {
CronnableSchedule(String... expressions) {
this(crons(expressions));
}

public CronnableSchedule(Cron... crons) {
private CronnableSchedule(Cron... crons) {
assert crons.length > 0;
this.crons = crons;
Arrays.sort(crons, CRON_COMPARATOR);
Expand All @@ -37,7 +32,15 @@ public long nextScheduledTimeAfter(long startTime, long time) {
assert time >= startTime;
long nextTime = Long.MAX_VALUE;
for (Cron cron : crons) {
nextTime = Math.min(nextTime, cron.getNextValidTimeAfter(time));
long nextValidTimeAfter = cron.getNextValidTimeAfter(time);
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@hub-cap hub-cap Aug 13, 2018

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Im curious, does the comparator not put these at either the begin or end of the sorted list here? should we just short circuit the loop once we find one of these outliers?

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@spinscale spinscale Aug 16, 2018

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the cron comparator is a string based comparator (which I don't think makes a ton of sense in context of a cron expression, maybe we can just remove it), and thus the sorting could be wrong in regards to finding the next valid time.

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@spinscale spinscale Aug 16, 2018

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example: 0 6 9 1 1 ? 2020 and 1 5 9 1 1 ? 2020. The sorting puts the first expression in front, but the second one is actually triggered first


boolean previousCronExpired = nextTime == -1;
boolean currentCronValid = nextValidTimeAfter > -1;
if (previousCronExpired && currentCronValid) {
nextTime = nextValidTimeAfter;
} else {
nextTime = Math.min(nextTime, nextValidTimeAfter);
}
}
return nextTime;
}
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25 changes: 18 additions & 7 deletions ...her/src/test/java/org/elasticsearch/xpack/watcher/trigger/schedule/CronScheduleTests.java
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Expand Up @@ -11,11 +11,15 @@
import org.elasticsearch.common.xcontent.XContentParser;
import org.elasticsearch.common.xcontent.json.JsonXContent;

import java.time.ZoneOffset;
import java.time.ZonedDateTime;

import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
import static org.hamcrest.Matchers.arrayWithSize;
import static org.hamcrest.Matchers.hasItemInArray;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.not;

public class CronScheduleTests extends ScheduleTestCase {
public void testInvalid() throws Exception {
Expand Down Expand Up @@ -54,18 +58,25 @@ public void testParseMultiple() throws Exception {
assertThat(crons, hasItemInArray("0 0/3 * * * ?"));
}

public void testMultipleCronsNextScheduledAfter() {
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@hub-cap hub-cap Aug 13, 2018

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should we add an expired cron entry to the list here too just to make sure?

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@spinscale spinscale Aug 16, 2018

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done

CronSchedule schedule = new CronSchedule("0 5 9 1 1 ? 2019", "0 5 9 1 1 ? 2020", "0 5 9 1 1 ? 2017");
ZonedDateTime start2019 = ZonedDateTime.of(2019, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC);
ZonedDateTime start2020 = ZonedDateTime.of(2020, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC);
long firstSchedule = schedule.nextScheduledTimeAfter(0, start2019.toInstant().toEpochMilli());
long secondSchedule = schedule.nextScheduledTimeAfter(0, start2020.toInstant().toEpochMilli());

assertThat(firstSchedule, is(not(-1L)));
assertThat(secondSchedule, is(not(-1L)));
assertThat(firstSchedule, is(not(secondSchedule)));
}

public void testParseInvalidBadExpression() throws Exception {
XContentBuilder builder = jsonBuilder().value("0 0/5 * * ?");
BytesReference bytes = BytesReference.bytes(builder);
XContentParser parser = createParser(JsonXContent.jsonXContent, bytes);
parser.nextToken();
try {
new CronSchedule.Parser().parse(parser);
fail("expected cron parsing to fail when using invalid cron expression");
} catch (ElasticsearchParseException pe) {
// expected
assertThat(pe.getCause(), instanceOf(IllegalArgumentException.class));
}
ElasticsearchParseException e = expectThrows(ElasticsearchParseException.class, () -> new CronSchedule.Parser().parse(parser));
assertThat(e.getCause(), instanceOf(IllegalArgumentException.class));
}

public void testParseInvalidEmpty() throws Exception {
Expand Down