feat: Setup flow_status_history table

- Setup table and populate
- Setup trigger
- Add status column to flows, setup permissions

hasura.planx.uk/metadata/tables.yaml

@@ -362,6 +362,13 @@
           - document_template
           - flow_id
         filter: {}
+- table:
+    name: flow_status_enum
+    schema: public
+  is_enum: true
+- table:
+    name: flow_status_history
+    schema: public
 - table:
     name: flows
     schema: public
@@ -527,7 +534,9 @@
           - version
         computed_fields:
           - data_merged
-        filter: {}
+        filter:
+          status:
+            _eq: online
         allow_aggregations: true
     - role: teamEditor
       permission:
@@ -550,16 +559,17 @@
     - role: api
       permission:
         columns:
+          - copied_from
+          - created_at
           - creator_id
-          - team_id
+          - data
+          - id
           - settings
           - slug
-          - created_at
+          - status
+          - team_id
           - updated_at
-          - copied_from
-          - id
           - version
-          - data
         filter: {}
         check: {}
         validate_input:
@@ -577,6 +587,7 @@
           - data
           - settings
           - slug
+          - status
           - team_id
         filter: {}
         check: null
@@ -595,6 +606,7 @@
           - data
           - settings
           - slug
+          - status
           - team_id
         filter:
           team:
@@ -1434,33 +1446,6 @@
 - table:
     name: submission_services_log
     schema: public
-  select_permissions:
-    - role: platformAdmin
-      permission:
-        columns:
-          - retry
-          - response
-          - event_id
-          - event_type
-          - status
-          - created_at
-          - flow_id
-          - session_id
-        filter: {}
-      comment: ""
-    - role: teamEditor
-      permission:
-        columns:
-          - retry
-          - response
-          - event_id
-          - event_type
-          - status
-          - created_at
-          - flow_id
-          - session_id
-        filter: {}
-      comment: ""
 - table:
     name: submission_services_summary
     schema: public

hasura.planx.uk/migrations/1715954131936_create_table_public_flow_status_enum/down.sql

@@ -0,0 +1,11 @@
+DROP TRIGGER IF EXISTS flow_status_history_trigger on flows;
+DROP FUNCTION IF EXISTS track_flow_status_history();
+
+DROP TABLE "public"."flow_status_history";
+
+alter table
+  "public"."flows" drop constraint "flows_status_fkey";
+
+ALTER TABLE flows DROP COLUMN "status";
+
+DROP TABLE "public"."flow_status_enum";

hasura.planx.uk/migrations/1715954131936_create_table_public_flow_status_enum/up.sql

@@ -0,0 +1,74 @@
+-- Setup enum table of possible values for flow.status
+CREATE TABLE "public"."flow_status_enum" (
+  "value" text NOT NULL,
+  "comment" text,
+  PRIMARY KEY ("value")
+);
+
+COMMENT ON TABLE "public"."flow_status_enum" IS E'An enum for tracking the status of a flow';
+
+INSERT INTO "public"."flow_status_enum"("value", "comment") VALUES (E'online', null);
+INSERT INTO "public"."flow_status_enum"("value", "comment") VALUES (E'offline', null);
+
+-- Add flow.status column
+alter table "public"."flows" add column "status" text
+ not null default 'online';
+
+alter table "public"."flows"
+  add constraint "flows_status_fkey"
+  foreign key ("status")
+  references "public"."flow_status_enum"
+  ("value") on update restrict on delete restrict;
+
+-- Create audit table to track changes to status
+-- Could be used for analytics or other audit features in future
+CREATE TABLE "public"."flow_status_history" (
+  "id" serial NOT NULL,
+  "flow_id" uuid NOT NULL,
+  "status" text NOT NULL,
+  "event_start" timestamptz NOT NULL,
+  "event_end" timestamptz,
+  PRIMARY KEY ("id"),
+  FOREIGN KEY ("flow_id") REFERENCES "public"."flows"("id") ON UPDATE restrict ON DELETE cascade,
+  FOREIGN KEY ("status") REFERENCES "public"."flow_status_enum"("value") ON UPDATE restrict ON DELETE restrict,
+  UNIQUE ("id")
+);
+
+COMMENT ON TABLE "public"."flow_status_history" IS E'Temporal table to track the status of a flow over time';
+
+-- Populate initial table values
+-- All flows have had status "online" since they were created
+INSERT INTO flow_status_history (flow_id, status, event_start)
+SELECT id, 'online', created_at
+FROM flows;
+
+-- Setup function which updates and adds audit records to flow_status_history
+CREATE OR REPLACE FUNCTION track_flow_status_history()
+RETURNS TRIGGER AS $$
+BEGIN
+    IF (TG_OP = 'UPDATE') THEN
+        -- End previous event
+        UPDATE flow_status_history
+        SET event_end = NOW()
+        WHERE flow_id = OLD.id AND event_end IS NULL;
+
+        -- Start new event
+        INSERT INTO flow_status_history (flow_id, status, event_start)
+        VALUES (NEW.id, OLD.status, NOW());
+
+    ELSIF (TG_OP = 'INSERT') THEN
+        -- Start new event
+        INSERT INTO flow_status_history (flow_id, status, event_start)
+        VALUES (NEW.id, NEW.status, NOW());
+    END IF;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+-- Trigger to call above function
+-- Called on insert or update to flows.status
+CREATE TRIGGER flow_status_history_trigger
+AFTER INSERT OR UPDATE OF status ON flows
+FOR EACH ROW
+EXECUTE FUNCTION track_flow_status_history();
+