Updated logic evaluating enable/disable index purge

services/alarm-logger/doc/index.rst

@@ -38,13 +38,13 @@ Automatic purge of Elasticsearch indices
 ****************************************
 
 To avoid issues related to a high number of Elasticsearch indices, automatic purge can be enabled in order to delete
-indices considered obsolete. This is done by setting the preference ``retention_period_days`` to a number larger
-or equal to 100. The default value is 0, i.e. automatic purge is disabled by default.
+indices considered obsolete. This is done by setting the preferences ``date_span_units`` and ``retain_indices_count`` such
+that they evaluate to a number larger or equal to 100. The default ``retain_indices_count`` is 0, i.e. automatic purge is disabled by default.
 
 The automatic purge is run using a cron expression defined in preference ``purge_cron_expr``, default is
 ``0 0 0 * * SUN``, i.e. midnight each Sunday. See the SpringDocumentation_ on how to define the cron expression.
 
 An Elasticsearch index is considered eligible for deletion if the last inserted message date is before current time
-minus ``retention_period_days``.
+minus the number of days computed from ``date_span_units`` and ``retain_indices_count``.
 
 .. _SpringDocumentation: https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/scheduling/support/CronExpression.html

services/alarm-logger/src/main/java/org/phoebus/alarm/logging/purge/ElasticIndexPurger.java

@@ -32,6 +32,7 @@
 import co.elastic.clients.elasticsearch.indices.DeleteIndexResponse;
 import org.phoebus.alarm.logging.ElasticClientHelper;
 import org.phoebus.alarm.logging.rest.AlarmLogMessage;
+import org.phoebus.alarm.logging.rest.AlarmLogSearchUtil;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnExpression;
 import org.springframework.scheduling.annotation.Scheduled;
@@ -46,16 +47,16 @@
 import java.util.logging.Logger;
 
 /**
- * Utility class purging Elasticsearch from indices considered obsolete based on the retention_period_time
- * application property. Any value below 100 (days) suppresses instantiation of this {@link Component}.
+ * Utility class purging Elasticsearch from indices considered obsolete based on the date_span_units and retain_indices_count
+ * application properties. If these result in a value below 100 (days), this {@link Component} will not be instantiated.
  * To determine last updated date of an index, each Elasticsearch index considered related to alarms is queried for last
  * inserted document. The message_time field of that document is compared to the retention period to determine
  * if the index should be deleted.
  * A cron expression application property is used to define when to run the purging process.
  */
 @Component
 // Enable only of retention period is >= 100 days
-@ConditionalOnExpression("#{T(java.lang.Integer).parseInt('${retention_period_days}') >= 100}")
+@ConditionalOnExpression("#{T(org.phoebus.alarm.logging.purge.ElasticIndexPurger.EnableCondition).getRetentionDays('${date_span_units}', '${retain_indices_count}') >= 100}")
 public class ElasticIndexPurger {
 
     private static final Logger logger = Logger.getLogger(ElasticIndexPurger.class.getName());
@@ -113,4 +114,31 @@ public void purgeElasticIndices() {
             logger.log(Level.WARNING, "Elastic query failed", e);
         }
     }
+
+    /**
+     * Helper class used to determine whether this service should be enabled or not
+     */
+    public static class EnableCondition {
+
+        /**
+         *
+         * @param dateSpanUnits Any of the values Y, M, W, D
+         * @param retainIndicesCountString String value of the retain_indices_count preference
+         * @return A number computed from input. In case input arguments are invalid (e.g. non-numerical value
+         * for retain_indices_coun), then 0 is returned to indicate that this {@link Component} should not be enabled.
+         */
+        @SuppressWarnings("unused")
+        public static int getRetentionDays(String dateSpanUnits, String retainIndicesCountString) {
+            int days = AlarmLogSearchUtil.getDateSpanInDays(dateSpanUnits);
+            if (days == -1) {
+                return 0;
+            }
+            try {
+                int retainIndicesCount = Integer.parseInt(retainIndicesCountString);
+                return days * retainIndicesCount;
+            } catch (NumberFormatException e) {
+                return 0;
+            }
+        }
+    }
 }

services/alarm-logger/src/main/java/org/phoebus/alarm/logging/rest/AlarmLogSearchUtil.java

@@ -360,21 +360,7 @@ public static List<String> findIndexNames(String baseIndexName, Instant fromInst
             if (fromIndex.equalsIgnoreCase(toIndex)) {
                 indexList.add(fromIndex);
             } else {
-                int indexDateSpanDayValue = -1;
-                switch (indexDateSpanUnits) {
-                    case "Y":
-                        indexDateSpanDayValue = 365;
-                        break;
-                    case "M":
-                        indexDateSpanDayValue = 30;
-                        break;
-                    case "W":
-                        indexDateSpanDayValue = 7;
-                        break;
-                    case "D":
-                        indexDateSpanDayValue = 1;
-                        break;
-                }
+                int indexDateSpanDayValue = getDateSpanInDays(indexDateSpanUnits);
                 indexList.add(fromIndex);
                 while (!fromIndex.equalsIgnoreCase(toIndex)) {
                     fromInstant = fromInstant.plus(indexDateSpanDayValue, ChronoUnit.DAYS);
@@ -386,4 +372,25 @@ public static List<String> findIndexNames(String baseIndexName, Instant fromInst
 
         return indexList;
     }
+
+    /**
+     *
+     * @param indexDateSpanUnits A single char string from [Y, M, W, D]
+     * @return Number of days corresponding to the unit, or -1 if the input does not match
+     * supported chars.
+     */
+    public static int getDateSpanInDays(String indexDateSpanUnits){
+        switch (indexDateSpanUnits) {
+            case "Y":
+                return 365;
+            case "M":
+                return 30;
+            case "W":
+                return 7;
+            case "D":
+                return 1;
+            default:
+                return -1;
+        }
+    }
 }

services/alarm-logger/src/main/resources/application.properties

@@ -46,10 +46,11 @@ thread_pool_size=4
 logging.level.org.springframework.web.filter.CommonsRequestLoggingFilter=INFO
 
 ############################## Index purge settings #######################
-# Minimum age (in days) of Elasticsearch indices eligible for automatic index purge.
-# Any value below 100 will disable automatic purge.
-# Non-numeric value will fail service startup.
-retention_period_days=0
+# How many indices to retain (e.g. if you have selected date_span_units as M and set the retain_indices_count to 6, then indices
+# older than 6 months will be deleted.
+# Number of days computed form this setting and date_span_units must be greater or equal to 100
+# for automatic purge to be enabled.
+retain_indices_count=0
 
 # Cron expression used by Spring scheduler running automatic purge, default every Sunday at midnight.
 # See https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/scheduling/support/CronExpression.html