LP#1672775 Action/Trigger retention interval SQL/IDL

Adds a new 'retention_interval' column for Action/Trigger Event
Definitions and an action_trigger.purge_events() function for deleting
events that have exceeded their configured retention time, including any
outputs linked to those events.

Signed-off-by: Bill Erickson <berickxx@gmail.com>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>

diff --git a/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.action-trigger-purge-events.sql b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.action-trigger-purge-events.sql
new file mode 100644 (file)
index 0000000..30f4dd6
--- /dev/null
+++ b/Open-ILS/src/sql/Pg/upgrade/XXXX.schema.action-trigger-purge-events.sql
@@ -0,0 +1,105 @@
+BEGIN;
+
+-- SELECT evergreen.upgrade_deps_block_check('1XXX', :eg_version);
+
+ALTER TABLE action_trigger.event_definition
+    ADD COLUMN retention_interval INTERVAL;
+
+CREATE OR REPLACE FUNCTION action_trigger.check_valid_retention_interval() 
+    RETURNS TRIGGER AS $_$
+BEGIN
+
+    /*
+     * 1. Retention intervals are alwyas allowed on active hooks.
+     * 2. On passive hooks, retention intervals are only allowed
+     *    when the event definition has a max_delay value and the
+     *    retention_interval value is greater than the difference 
+     *    beteween the delay and max_delay values.
+     */ 
+    PERFORM TRUE FROM action_trigger.hook 
+        WHERE key = NEW.hook AND NOT passive;
+
+    IF FOUND THEN
+        RETURN NEW;
+    END IF;
+
+    IF NEW.max_delay IS NOT NULL THEN
+        IF EXTRACT(EPOCH FROM NEW.retention_interval) > 
+            ABS(EXTRACT(EPOCH FROM (NEW.max_delay - NEW.delay))) THEN
+            RETURN NEW; -- all good
+        ELSE
+            RAISE EXCEPTION 'retention_interval is too short';
+        END IF;
+    ELSE
+        RAISE EXCEPTION 'retention_interval requires max_delay';
+    END IF;
+END;
+$_$ LANGUAGE PLPGSQL;
+
+CREATE TRIGGER is_valid_retention_interval 
+    BEFORE INSERT OR UPDATE ON action_trigger.event_definition
+    FOR EACH ROW WHEN (NEW.retention_interval IS NOT NULL)
+    EXECUTE PROCEDURE action_trigger.check_valid_retention_interval();
+
+CREATE OR REPLACE FUNCTION action_trigger.purge_events() RETURNS VOID AS $_$
+/**
+  * Deleting expired events without simultaneously deleting their outputs
+  * creates orphaned outputs.  Deleting their outputs and all of the events 
+  * linking back to them, plus any outputs those events link to is messy and 
+  * inefficient.  It's simpler to handle them in 2 sweeping steps.
+  *
+  * 1. Delete expired events.
+  * 2. Delete orphaned event outputs.
+  *
+  * This has the added benefit of removing outputs that may have been
+  * orphaned by some other process.  Such outputs are not usuable by
+  * the system.
+  *
+  * This does not guarantee that all events within an event group are
+  * purged at the same time.  In such cases, the remaining events will
+  * be purged with the next instance of the purge (or soon thereafter).
+  * This is another nod toward efficiency over completeness of old 
+  * data that's circling the bit bucket anyway.
+  */
+BEGIN
+
+    DELETE FROM action_trigger.event WHERE id IN (
+        SELECT evt.id
+        FROM action_trigger.event evt
+        JOIN action_trigger.event_definition def ON (def.id = evt.event_def)
+        WHERE def.retention_interval IS NOT NULL 
+            AND evt.state <> 'pending'
+            AND evt.update_time < (NOW() - def.retention_interval)
+    );
+
+    WITH linked_outputs AS (
+        SELECT templates.id AS id FROM (
+            SELECT DISTINCT(template_output) AS id
+                FROM action_trigger.event WHERE template_output IS NOT NULL
+            UNION
+            SELECT DISTINCT(error_output) AS id
+                FROM action_trigger.event WHERE error_output IS NOT NULL
+            UNION
+            SELECT DISTINCT(async_output) AS id
+                FROM action_trigger.event WHERE async_output IS NOT NULL
+        ) templates
+    ) DELETE FROM action_trigger.event_output
+        WHERE id NOT IN (SELECT id FROM linked_outputs);
+
+END;
+$_$ LANGUAGE PLPGSQL;
+
+
+/* -- UNDO --
+
+BEGIN;
+DROP FUNCTION IF EXISTS action_trigger.purge_events();
+DROP TRIGGER IF EXISTS is_valid_retention_interval ON action_trigger.event_definition;
+DROP FUNCTION IF EXISTS action_trigger.check_valid_retention_interval();
+ALTER TABLE action_trigger.event_definition DROP COLUMN retention_interval;
+COMMIT;
+
+*/
+
+COMMIT;
+

diff --git a/Open-ILS/src/sql/Pg/upgrade/YYYY.data.action-trigger-purge-events.sql b/Open-ILS/src/sql/Pg/upgrade/YYYY.data.action-trigger-purge-events.sql
new file mode 100644 (file)
index 0000000..1c79052
--- /dev/null
+++ b/Open-ILS/src/sql/Pg/upgrade/YYYY.data.action-trigger-purge-events.sql
@@ -0,0 +1,22 @@
+BEGIN;
+
+-- SELECT evergreen.upgrade_deps_block_check('1XXX', :eg_version);
+
+UPDATE action_trigger.hook SET passive = FALSE WHERE key IN (
+    'format.po.html',
+    'format.po.pdf',
+    'format.selfcheck.checkout',
+    'format.selfcheck.items_out',
+    'format.selfcheck.holds',
+    'format.selfcheck.fines',
+    'format.acqcle.html',
+    'format.acqinv.html',
+    'format.acqli.html',
+    'aur.ordered',
+    'aur.received',
+    'aur.cancelled',
+    'aur.created',
+    'aur.rejected'
+);
+
+COMMIT;