Track becomes unusable from collection after exiting session

[aviral-public]

When I first load a track on deck, it plays well. Otherwise crashes

[aviral-public]

Ignore, I just uninstalled everything and reinstalled it all, classic "turn off and then on again" and it works

[0xf4b1]

Hey, this happens when you restart the server without restarting traktor because the server has some state, then traktor may know about some items the server hasn't seen before, it shouldn't be necessary to reinstall everything, just restart traktor ;) If you find other scenarios let me know!

[aviral-public]

@0xf4b1 Consider this sequence of user action:

step 1. start the server with - bin/traktor-streaming-proxy
step 2. start traktor with - "DYLD_INSERT_LIBRARIES=./SecTrustEvaluateStub.dylib "/Applications/Native Instruments/Traktor Pro 3/Traktor.app/Contents/MacOS/Traktor""
step 3. User does not go to beatport section, but drags a track from track collection which was previously imported from youtube, user gets following error

step 4: user searches for the same track on beatport search

step 5: User does nothing on the search page, goes back to Track Collection, and tries the same track again on deck A and tries another track which he has not searched for, on deck B

What happens is that the track which was searched for in current session downloads successfully, but the other fails.

---

As you can see, currently, I have to basically keep my traktor app open and server on while I plan all the tracks. If I restart the computer, everything I added to my library kind of "becomes corrupt" until I search for it again.

Any idea what could be wrong? I'm also happy to make a PR if you can guide me in the right direction. Here is the server log. the failure is before i searched for the track, the successful download is after.

The same issue does not happen if I keep the proxy server running but only restart traktor. however, since I shut my computer down every day, it basically forces me to never be able to build a youtube-based collection.

base/java.lang.Thread.run(Thread.java:1575)
187881 [eventLoopGroupProxy-4-9] INFO io.ktor.server.Application  - 500 Internal Server Error: GET - /v4/catalog/tracks/687245758093922931/download/ in 1ms
225340 [eventLoopGroupProxy-3-4] DEBUG io.netty.handler.ssl.SslHandler  - [id: 0x24b8fd19, L:/127.0.0.1:8443 - R:/127.0.0.1:64815] HANDSHAKEN: protocol:TLSv1.2 cipher suite:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
225620 [eventLoopGroupProxy-4-10] INFO io.ktor.server.Application  - 200 OK: GET - /v4/catalog/search in 279ms
227729 [eventLoopGroupProxy-3-5] DEBUG io.netty.handler.ssl.SslHandler  - [id: 0x44adad59, L:/127.0.0.1:8443 - R:/127.0.0.1:64821] HANDSHAKEN: protocol:TLSv1.2 cipher suite:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
228216 [eventLoopGroupProxy-4-11] INFO io.ktor.server.Application  - 200 OK: GET - /v4/catalog/search in 486ms
228261 [eventLoopGroupProxy-3-5] DEBUG io.netty.handler.ssl.SslHandler  - [id: 0x44adad59, L:/127.0.0.1:8443 - R:/127.0.0.1:64821] Swallowing a harmless 'connection reset by peer / broken pipe' error that occurred while writing close_notify in response to the peer's close_notify
java.net.SocketException: Connection reset
	at java.base/sun.nio.ch.SocketChannelImpl.throwConnectionReset(SocketChannelImpl.java:403)
	at java.base/sun.nio.ch.SocketChannelImpl.implRead(SocketChannelImpl.java:435)
	at java.base/sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:493)
	at io.netty.buffer.PooledByteBuf.setBytes(PooledByteBuf.java:255)
	at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1132)
	at io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:356)
	at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:151)
	at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:796)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:732)
	at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:658)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:998)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:1575)
228264 [eventLoopGroupProxy-3-6] DEBUG io.netty.handler.ssl.SslHandler  - [id: 0xe332e78c, L:/127.0.0.1:8443 - R:/127.0.0.1:64826] HANDSHAKEN: protocol:TLSv1.2 cipher suite:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
232504 [eventLoopGroupProxy-3-7] DEBUG io.netty.handler.ssl.SslHandler  - [id: 0xdf562458, L:/127.0.0.1:8443 - R:/127.0.0.1:64831] HANDSHAKEN: protocol:TLSv1.2 cipher suite:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
235353 [eventLoopGroupProxy-4-1] INFO io.ktor.server.Application  - 200 OK: GET - /v4/catalog/tracks/687245758093922931/download/ in 2848ms
235359 [eventLoopGroupProxy-3-1] DEBUG io.netty.handler.ssl.SslHandler  - [id: 0x733430c3, L:/127.0.0.1:8443 - R:/127.0.0.1:64841] HANDSHAKEN: protocol:TLSv1.2 cipher suite:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
235361 [eventLoopGroupProxy-4-2] INFO io.ktor.server.Application  - 200 OK: HEAD - /output.mp4 in 0ms
235362 [eventLoopGroupProxy-4-2] INFO io.ktor.server.Application  - 200 OK: GET - /output.mp4 in 0ms

[aviral-public]

@0xf4b1 also, sorry for annoying you almost on NYE, but that's when I gots to use my barely existent DJ skills for friends haha. Happy New Years!

[0xf4b1]

Hey, the scenario what you describe is basically what I meant with the state loss when you restart the server. It does not remember the track ids from a previous session, so when Traktor asks for a track from its library, it does not exist on the server.

So what code-wise happens is that whenever you search tracks, they are processed in

traktor-streaming-proxy/src/main/kotlin/Main.kt

Line 64 in 76f65f0

fun processTracks(id: Int, tracks: List<Track>): List<TrackResponse> {

which stores the source of a track id in trackIdToSource and a mapping of traktor track id to actual source track id in traktorIdToTrackId. If the two maps would be persistent, I believe it should work after restart.

Maybe there is even an easier solution because in the scenario where traktor already downloaded the track and has it available in the library, it will not download the track again and possibly just need some response from the server that must not be the actual real track again 🤔