NNTP shares: the account's connections shared by priority

The coordinator (38) and the prober (8) had a fixed split; with history
paused the coordinator's stood idle while the prober's were its limit.
nntp_shares: each process syncs every 15 s (priority, minimum, what it could
use, what it has open) and gets what it may open: minimums first, then by
priority what each wants, growing only into connections the others closed
or gave up. The pool's size and the prober's lanes follow the grant; the
coordinator doubles its want while work waits for a connection, else asks
for its peak in use and a margin; the prober wants its maximum unless the
queue is dry. Claims scale with the lanes.

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

commands/coordinator_run.ts

@@ -8,6 +8,7 @@ import Settler from '#services/settler'
 import RangeBlocks from '#services/range_blocks'
 import Leases from '#services/leases'
 import NntpPool from '#services/nntp_pool'
+import { NntpShare } from '#services/nntp_shares'
 import coordinatorConfig from '#config/coordinator'
 
 const TICK_MS = 2000
@@ -43,6 +44,7 @@ export default class CoordinatorRun extends BaseCommand {
     const [index, count] = (this.shard ?? '1/1').split('/').map(Number)
     if (!(count >= 1 && index >= 1 && index <= count)) throw new Error(`--shard: "i/n" with 1 <= i <= n, not "${this.shard}"`)
     const prefetcher = new Prefetcher({ index: index - 1, count })
+    const share = new NntpShare(count > 1 ? `coordinator ${index}/${count}` : 'coordinator', coordinatorConfig.nntpShares.coordinatorPriority, coordinatorConfig.nntpMinConnections, coordinatorConfig.nntpConnections)
     const main = index === 1
     let stopping = false
     let stopped: () => void
@@ -55,6 +57,21 @@ export default class CoordinatorRun extends BaseCommand {
       await done
     })
     this.logger.info(count > 1 ? `Coordinator started (shard ${index}/${count}${main ? '' : ', prefetching only'}).` : 'Coordinator started.')
+    // The pool's size: its share of the account's connections, the prober the rest (app/services/nntp_shares.ts).
+    // Before the first connection: until then it's NNTP_CONNECTIONS.
+    const first = await NntpPool.share(share)
+    this.logger.info(`NNTP share: ${first.granted} connections.`)
+    const sharing = (async () => {
+      while (!stopping) {
+        try {
+          const { was, granted } = await NntpPool.share(share)
+          if (granted !== was) this.logger.info(`NNTP share: ${granted} connections (was ${was}).`)
+        } catch (error: any) {
+          this.logger.error(`NNTP share failed: ${error.message}`)
+        }
+        for (let waited = 0; waited < coordinatorConfig.nntpShares.everyMs && !stopping; waited += TICK_MS) await sleep(TICK_MS)
+      }
+    })()
     // Two loops: the prefetcher's ticks don't wait for merging or planning (a merge round
     // of up to MERGE_BUDGET_MS left the connections idle once their targets were fetched).
     const prefetching = (async () => {
@@ -126,12 +143,13 @@ export default class CoordinatorRun extends BaseCommand {
       }
       await sleep(TICK_MS)
     }
-    await Promise.all([prefetching, blocks])
+    await Promise.all([prefetching, blocks, sharing])
     // The chunks in flight, for at most STOP_WAIT_MS (a connection the server holds back can take minutes); then closed.
     const waitUntil = Date.now() + STOP_WAIT_MS
     while (prefetcher.active > 0 && Date.now() < waitUntil) await sleep(200)
     if (prefetcher.active > 0) this.logger.info(`Closing ${prefetcher.active} connections still fetching.`)
     await NntpPool.close()
+    await share.leave().catch(() => {})
     this.logger.info('Coordinator stopped.')
     stopped!()
     await this.terminate()