Seed relay: nodes get their headers through the seed API

The seed API keeps a pool of NNTP connections (SEED_NNTP_CONNECTIONS) and
serves GET /api/v1/seed/ranges/:id/chunk?from=&to= for leased ranges:
the gzip stream the news server sent, passed on unopened. seed:node fetches
that way by default (SEED_FETCH=relay), so a node needs only a token and
SEED_CONNECTIONS; SEED_FETCH=direct keeps its own NNTP connections. All
fetching then comes from the indexer's IP (the account allows two).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/functional/seed_api.spec.ts

@@ -5,6 +5,8 @@ import testUtils from '@adonisjs/core/services/test_utils'
 import SeedOrchestrator from '#services/SeedOrchestrator'
 import QueueService from '#services/QueueService'
 import indexerConfig from '#config/indexer'
+import SeedFetchPool from '#services/SeedFetchPool'
+import { deflateSync } from 'node:zlib'
 import { segmentFromHeader } from '#lib/ingest/segment'
 import { FileAggregator } from '#lib/aggregate/index'
 import { toFragment, toSeedFile, type SeedBatch } from '#lib/seed/wire'
@@ -99,4 +101,31 @@ test.group('Seed API', (group) => {
     assert.equal(row.status, 'queued')
     assert.equal(row.attempts, 0)
   })
+
+  test('relay: a leased range gets its overview chunks through the API', async ({ client, assert }) => {
+    const token = await SeedOrchestrator.issueToken('relay-node')
+    await db.table('seed_ranges').insert({ group_name: 'alt.binaries.test', start_id: 1, end_id: 100, next_id: 1 })
+    const auth = { authorization: `Bearer ${token}` }
+    const range = (await client.post('/api/v1/seed/lease').headers(auth)).body().range
+    const fetch = SeedFetchPool.fetch
+    const connections = indexerConfig.seed.nntpConnections
+    const asked: unknown[] = []
+    SeedFetchPool.fetch = async (group, from, to) => {
+      asked.push([group, from, to])
+      return deflateSync(Buffer.from('5\tsubject\r\n'))
+    }
+    try {
+      indexerConfig.seed.nntpConnections = 0
+      ;(await client.get(`/api/v1/seed/ranges/${range.id}/chunk`).qs({ from: 1, to: 50 }).headers(auth)).assertStatus(503)
+      indexerConfig.seed.nntpConnections = 1
+      const chunk = await client.get(`/api/v1/seed/ranges/${range.id}/chunk`).qs({ from: 50, to: 500 }).headers(auth)
+      chunk.assertStatus(200)
+      // Clamped to the range.
+      assert.deepEqual(asked, [['alt.binaries.test', 50, 100]])
+      ;(await client.get(`/api/v1/seed/ranges/${range.id}/chunk`).qs({ from: 200, to: 300 }).headers(auth)).assertStatus(400)
+    } finally {
+      SeedFetchPool.fetch = fetch
+      indexerConfig.seed.nntpConnections = connections
+    }
+  })
 })