Never move last seen back or first seen forward (closes #162)

Some RIS collectors send updates days old while they catch up on a
backlog. Every update to a stored AS, peering or peer set last_seen to
the update's time, even an older one, and never lowered first_seen. An
AS page could then list a peer first seen after it was last seen.

The update statements for asns, peerings and bgp_peers now keep the
earlier of the stored and new first_seen and the later of the stored
and new last_seen, with MIN and MAX in the SQL. The batch and the
single-row writes share each statement. GetOrCreateASN returns the
times the row now holds. Route times are unchanged.

Model: opus-5-5

internal/database/database_internal_test.go

@@ -1961,29 +1961,26 @@ func TestUpdatePeerBatchStoresTheEarliestAndLatestTimesOfANewPeer(
 	}
 }
 
-// backlogAge is how much older the second write is than the first in the tests
+// backlogAge is how much older one write is than the other in the tests of
-// of first_seen and last_seen, as when a collector catches up on a backlog.
+// first_seen and last_seen, as when a collector catches up on a backlog.
 const backlogAge = 24 * time.Hour
 
 // batchSpan is how much earlier a batch's First is than its Last in the tests
 // of first_seen and last_seen.
 const batchSpan = time.Hour
 
-// TestOlderWriteKeepsLastSeenAndLowersFirstSeen writes a row of each of asns,
+// TestWritesKeepEarliestFirstSeenAndLatestLastSeen writes a row of each of
-// peerings and bgp_peers through each function that writes one: first at a
+// asns, peerings and bgp_peers through each function that writes one, at a
-// newer time, then at an older one. Each row keeps the newer last_seen and
+// newer time and at an older one. Each row takes the older write's First as
-// takes the older first_seen. Each function writes a row of its own. A batch
+// first_seen and the newer write's Last as last_seen. The test writes in both
-// write's First is batchSpan before its Last, so the test catches the two
+// orders, each in a database of its own. Newer then older is a collector
-// swapped. A single-row write takes one time.
+// catching up on a backlog; older then newer is a feed that arrives in order.
-func TestOlderWriteKeepsLastSeenAndLowersFirstSeen(t *testing.T) {
+// Each function writes a row of its own. A batch write's First is batchSpan
+// before its Last, so the test catches the two swapped. A single-row write
+// takes one time.
+func TestWritesKeepEarliestFirstSeenAndLatestLastSeen(t *testing.T) {
 	t.Parallel()
 
-	db, err := New(&config.Config{StateDir: t.TempDir()}, logger.New())
-	if err != nil {
-		t.Fatalf("failed to create database: %v", err)
-	}
-	defer func() { _ = db.Close() }()
-
 	const (
 		batchASN, singleASN = 64500, 64501
 		peerASN             = 64502
@@ -1994,21 +1991,34 @@ func TestOlderWriteKeepsLastSeenAndLowersFirstSeen(t *testing.T) {
 			"WHERE peer_ip = ?"
 	)
 
-	checkOlderWrite(t, db, func(seen SeenTimes) error {
+	for name, olderFirst := range map[string]bool{
+		"newer then older": false,
+		"older then newer": true,
+	} {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			db, err := New(&config.Config{StateDir: t.TempDir()}, logger.New())
+			if err != nil {
+				t.Fatalf("failed to create database: %v", err)
+			}
+			defer func() { _ = db.Close() }()
+
+			checkSeenTimes(t, db, olderFirst, func(seen SeenTimes) error {
 				return db.GetOrCreateASNBatch(map[int]SeenTimes{batchASN: seen})
 			}, batchSpan, asnQuery, batchASN)
 
-	checkOlderWrite(t, db, func(seen SeenTimes) error {
+			checkSeenTimes(t, db, olderFirst, func(seen SeenTimes) error {
 				_, err := db.GetOrCreateASN(singleASN, seen.Last)
 
 				return err
 			}, 0, asnQuery, singleASN)
 
-	checkOlderWrite(t, db, func(seen SeenTimes) error {
+			checkSeenTimes(t, db, olderFirst, func(seen SeenTimes) error {
 				return db.RecordPeering(batchASN, singleASN, seen)
 			}, batchSpan, peeringQuery, batchASN, singleASN)
 
-	checkOlderWrite(t, db, func(seen SeenTimes) error {
+			checkSeenTimes(t, db, olderFirst, func(seen SeenTimes) error {
 				return db.UpdatePeerBatch(map[string]PeerUpdate{
 					testV4PeerIP: {
 						PeerIP: testV4PeerIP, PeerASN: peerASN,
@@ -2018,18 +2028,21 @@ func TestOlderWriteKeepsLastSeenAndLowersFirstSeen(t *testing.T) {
 				})
 			}, batchSpan, peerQuery, testV4PeerIP)
 
-	checkOlderWrite(t, db, func(seen SeenTimes) error {
+			checkSeenTimes(t, db, olderFirst, func(seen SeenTimes) error {
-		return db.UpdatePeer(testPeerIP, peerASN, ristypes.MessageTypeUpdate,
+				return db.UpdatePeer(testPeerIP, peerASN,
-			seen.Last)
+					ristypes.MessageTypeUpdate, seen.Last)
 			}, 0, peerQuery, testPeerIP)
+		})
+	}
 }
 
-// checkOlderWrite calls write twice, each time with First span before Last:
+// checkSeenTimes calls write twice, each time with First span before Last: at
-// first at newer times, then at times backlogAge older. It checks that query,
+// newer times and at times backlogAge older. It writes the older times first
-// given args, reads the older write's First as first_seen and the newer write's
+// when olderFirst is true. It checks that query, given args, reads the older
-// Last as last_seen.
+// write's First as first_seen and the newer write's Last as last_seen.
-func checkOlderWrite(
+func checkSeenTimes(
-	t *testing.T, db *Database, write func(seen SeenTimes) error,
+	t *testing.T, db *Database, olderFirst bool,
+	write func(seen SeenTimes) error,
 	span time.Duration, query string, args ...any,
 ) {
 	t.Helper()
@@ -2041,7 +2054,12 @@ func checkOlderWrite(
 		Last:  newer.Last.Add(-backlogAge),
 	}
 
-	for _, seen := range []SeenTimes{newer, older} {
+	writes := []SeenTimes{newer, older}
+	if olderFirst {
+		writes = []SeenTimes{older, newer}
+	}
+
+	for _, seen := range writes {
 		err := write(seen)
 		if err != nil {
 			t.Fatalf("writing first %s, last %s: %v", seen.First, seen.Last, err)