(enh): simple ttl caching ssh sessions

apps/deepsirius-ui/src/server/api/trpc.ts

@@ -32,6 +32,7 @@ import { env } from '~/env.mjs';
 import { getServerAuthSession } from '~/server/auth';
 import { prisma } from '~/server/db';
 import { ssh } from '~/server/ssh';
+import { cache as sshCache } from '../ssh-cache';
 
 type CreateContextOptions = {
   session: Session | null;
@@ -154,13 +155,21 @@ const ensureSSHConnection = t.middleware(async ({ ctx, next }) => {
     throw new TRPCError({ code: 'UNAUTHORIZED' });
   }
 
-  const connection = await ctx.ssh.connect({
-    username: ctx.session.user.name,
-    privateKey: ctx.privateKey,
-    host: env.SSH_HOST,
-    port: 22,
-    passphrase: env.PRIVATE_KEY_PASSPHRASE,
-  });
+  let connection = sshCache.get(ctx.session.user.name);
+  if (!connection) {
+    connection = await ctx.ssh.connect({
+      username: ctx.session.user.name,
+      privateKey: ctx.privateKey,
+      host: env.SSH_HOST,
+      port: 22,
+      passphrase: env.PRIVATE_KEY_PASSPHRASE,
+    });
+    if (!connection) {
+      throw new TRPCError({ code: 'INTERNAL_SERVER_ERROR' });
+    }
+
+    sshCache.set(ctx.session.user.name, connection, 1000 * 60 * 6);
+  }
 
   const res = await next({
     ctx: {
@@ -170,8 +179,6 @@ const ensureSSHConnection = t.middleware(async ({ ctx, next }) => {
     },
   });
 
-  connection.dispose();
-
   return res;
 });
 

apps/deepsirius-ui/src/server/ssh-cache.ts

@@ -0,0 +1,49 @@
+/** The ISC License
+
+Copyright (c) 2010-2023 Isaac Z. Schlueter and Contributors
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+import type { NodeSSH } from 'node-ssh';
+
+export const cache = {
+  data: new Map<PropertyKey, NodeSSH>(),
+  timers: new Map<PropertyKey, ReturnType<typeof setTimeout>>(),
+  set: (k: PropertyKey, v: NodeSSH, ttl: number) => {
+    if (cache.timers.has(k)) {
+      clearTimeout(cache.timers.get(k));
+    }
+    cache.timers.set(
+      k,
+      setTimeout(() => cache.delete(k), ttl),
+    );
+    cache.data.set(k, v);
+  },
+  get: (k: PropertyKey) => cache.data.get(k),
+  has: (k: PropertyKey) => cache.data.has(k),
+  delete: (k: PropertyKey) => {
+    if (cache.timers.has(k)) {
+      clearTimeout(cache.timers.get(k));
+    }
+    cache.timers.delete(k);
+    cache.data.get(k)?.dispose();
+    return cache.data.delete(k);
+  },
+  clear: () => {
+    cache.data.clear();
+    for (const v of cache.timers.values()) {
+      clearTimeout(v);
+    }
+    cache.timers.clear();
+  },
+};