concurrent backup

download from all pdses at once. I don't know how to do concurrent sqlite transations

index.js

@@ -4,13 +4,24 @@ import {iterateAtpRepo} from '@atcute/car';
 import {CidLinkWrapper} from "@atcute/cid";
 import {DidResolver} from "@atproto/identity";
 import got from "got";
-import * as fs from "fs";
+import {writeFile} from "fs/promises";
+import {existsSync, mkdirSync} from 'fs';
 
-try {fs.mkdirSync("blobs")} catch(e) {}
-try {fs.mkdirSync("repos")} catch(e) {}
+try {mkdirSync("blobs")} catch(e) {}
+try {mkdirSync("repos")} catch(e) {}
 
 var didres = new DidResolver({});
-var getPds = async did => (await didres.resolve(did)).service.find(s => s.id == "#atproto_pds")?.serviceEndpoint;
+async function getPds(did) {
+	try {
+		var doc = await didres.resolve(did);
+	} catch(error) {
+		console.error("resolve", did, error.message);
+		return null;
+	}
+	return doc?.service?.find(s => s.id == "#atproto_pds")?.serviceEndpoint;
+}
+
+
 var w = got.extend({
 	hooks: {
 		beforeRequest: [({url, method}) => console.log(`${method} ${url}`)],
@@ -37,7 +48,7 @@ var insert_statement = await db.prepare(`INSERT INTO records VALUES (?,?,?,?,?,?
 
 async function getRepo(pds, did) {
 	var repo = await w.get(`${pds}/xrpc/com.atproto.sync.getRepo?did=${did}`).buffer();
-	fs.writeFileSync(`repos/${did.replaceAll(':','-')}`, repo);
+	await writeFile(`repos/${did.replaceAll(':','-')}`, repo);
 	return repo;
 }
 
@@ -55,8 +66,8 @@ async function processRepo(did, repo) {
 			still_exists: null
 		};
 	}
-	console.debug("begin transaction");
-	await db.exec(`BEGIN TRANSACTION`);
+	//console.debug("begin transaction");
+	//await db.exec(`BEGIN TRANSACTION`);
 	try {
 		for (let entry of iterateAtpRepo(repo)) {
 			recordCounts[entry.collection] ||= {now: 0, new: 0};
@@ -107,8 +118,8 @@ async function processRepo(did, repo) {
 			]);
 		}
 	}
-	console.debug("commit");
-	await db.exec(`COMMIT`);
+	//console.debug("commit");
+	//await db.exec(`COMMIT`);
 	console.log(did, `${rdids.size} related dids`);
 	rdids.delete(did);
 	return rdids;
@@ -116,9 +127,9 @@ async function processRepo(did, repo) {
 
 async function saveBlob(pds, did, cid) {
 	var fp = `blobs/${cid}`;
-	if (fs.existsSync(fp)) return;
+	if (existsSync(fp)) return;
 	var blob = await w.get(`${pds}/xrpc/com.atproto.sync.getBlob?did=${did}&cid=${cid}`).buffer();
-	fs.writeFileSync(fp, blob);
+	await writeFile(fp, blob);
 }
 
 async function saveBlobs(pds, did) {
@@ -144,7 +155,7 @@ async function backup(did) {
 		return;
 	}
 	var repo = await getRepo(pds, did).catch(error => console.error(error.message));
-	if (repo) var rdids = await processRepo(did, repo);
+	if (repo) var rdids = await processRepo(did, repo).catch(error => console.error(error.message));
 	await saveBlobs(pds, did).catch(error => console.error(error.message));
 	return rdids;
 }
@@ -152,25 +163,32 @@ async function backup(did) {
 
 async function backupRecursive(dids, depth = 1) {
 	console.log(`backup ${dids.size} dids depth ${depth}`);
-	if (!depth) {
-		for (let did of dids) await backup(did).catch(error => console.error(error.stack));
-		return;
-	}
-	var allrdids = new Set();
-	var index = -1;
+
+	var pds2dids = {};
 	for (let did of dids) {
-		index++;
-		if (backedUpDids.includes(did)) continue;
-		backedUpDids.push(did);
-		console.log(`${index} / ${dids.size}`);
-		try {
-			let rdids = await backup(did);
-			rdids?.forEach(rdid => allrdids.add(rdid));
-		} catch (error) {
-			console.error(error.stack);
-		}
+		let pds = await getPds(did);
+		(pds2dids[pds] ||= new Set()).add(did);
 	}
-	await backupRecursive(allrdids, depth - 1);
+	console.log(`backing up from ${Object.keys(pds2dids).length} PDSes at once`);
+
+	var allrdids = new Set();
+	await Promise.all(Object.entries(pds2dids).map(async ([pds, dids]) => {
+		var index = -1;
+		for (let did of dids) {
+			index++;
+			if (backedUpDids.includes(did)) continue;
+			backedUpDids.push(did);
+			console.log(`[${pds}] ${index} / ${dids.size}`);
+			try {
+				let rdids = await backup(did);
+				rdids?.forEach(rdid => allrdids.add(rdid));
+			} catch (error) {
+				console.error(error.stack);
+			}
+		}
+	}));
+
+	if (depth) await backupRecursive(allrdids, depth - 1);
 }