Slack digest for #general - 2019-07-08

[Apache Pulsar Slack <ap...@gmail.com>]

2019-07-07 23:56:30 UTC - Jim Lambert: Sort of stuck and looking for some suggestions…
I’m running standalone.  I’ve got the TLS transport working and tested it successfully, but when I try to enable authen/authz it fails.
standalone.conf authen/authz changes:
```
proxyRoles=standalone-puslar-proxy
authenticateOriginalAuthData=true
authenticationEnabled=true
authenticationProviders=org.apache.pulsar.broker.authentication.AuthenticationProviderTls
forwardAuthorizationCredentials=true
superUserRoles=standalone-pulsar-admin,standalone-puslar-proxy 
brokerClientAuthenticationPlugin=org.apache.pulsar.client.impl.auth.AuthenticationTls
brokerClientAuthenticationParameters=tlsCertFile:/pulsar/proxy-cert.pem,tlsKeyFile:/pulsar/proxy-key.pem
brokerClientTrustCertsFilePath=/pulsar/rootCA.pem
brokerClientTlsEnabled=true
```
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2019-07-07 23:56:34 UTC - Jim Lambert: here’s the error from the log:
```23:09:45.587 [main] INFO  org.apache.pulsar.functions.worker.WorkerService - Created Pulsar client
23:09:45.752 [pulsar-client-io-70-1] INFO  org.apache.pulsar.client.impl.ConnectionPool - [[id: 0xecf2554e, L:/127.0.0.1:37584 - R:127.0.0.1/127.0.0.1:6650]] Connected to server
23:09:45.763 [pulsar-io-49-1] INFO  org.apache.pulsar.broker.service.ServerCnx - New connection from /127.0.0.1:37584
23:09:45.770 [pulsar-io-49-1] WARN  org.apache.pulsar.broker.service.ServerCnx - [/127.0.0.1:37584] Unable to authenticate: Unsupported authentication mode: none
23:09:45.775 [pulsar-io-49-1] INFO  org.apache.pulsar.broker.service.ServerCnx - Closed connection from /127.0.0.1:37584
23:09:45.775 [pulsar-client-io-70-1] WARN  org.apache.pulsar.client.impl.ClientCnx - [127.0.0.1/127.0.0.1:6650] Got exception IllegalArgumentException : null
java.lang.IllegalArgumentException: null
	at com.google.common.base.Preconditions.checkArgument(Preconditions.java:108) ~[com.google.guava-guava-21.0.jar:?]
	at org.apache.pulsar.client.impl.ClientCnx.handleError(ClientCnx.java:527) ~[org.apache.pulsar-pulsar-client-original-2.3.1.jar:2.3.1]
	at org.apache.pulsar.common.api.PulsarDecoder.channelRead(PulsarDecoder.java:157) ~[org.apache.pulsar-pulsar-common-2.3.1.jar:2.3.1]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:323) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:297) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:799) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:433) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:330) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:909) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) [io.netty-netty-all-4.1.32.Final.jar:4.1.32.Final]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181]
```
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2019-07-08 08:29:55 UTC - Dennis Sehalic: @Dennis Sehalic has joined the channel
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2019-07-08 08:41:17 UTC - Dennis Sehalic: Hello, I'm new here
Been looking at Pulsar and been trying it out, really like it. One use case we have is a multicast/broadcast scenario where multiple clients sometimes needs to get the same messages (multiple clients looking at the same resource and event messages for the resource are shown close to real time in each client). As far as I understand it Pulsar doesn't have a multicast subscription mode, any tips on a best practice going about solving this?
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2019-07-08 08:42:13 UTC - Sijie Guo: you can just create as many subscriptions as needed.
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2019-07-08 08:42:22 UTC - Sijie Guo: the messages are broadcasted to subscriptoins
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2019-07-08 08:42:24 UTC - Venugopal Doddi: NVM @Sijie Guo i have figured out this. We are getting the metrics now.
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2019-07-08 08:42:46 UTC - Sijie Guo: sorry that I missed this message
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2019-07-08 08:44:31 UTC - Dennis Sehalic: aha okay, I'll look into that thanks
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2019-07-08 08:56:05 UTC - Dennis Sehalic: @Sijie Guo that should work. a followup question though, are there any performance/resource considerations having many (say 100+) subscriptions to a single topic, or rephrased is there a limit you probably should stay below?
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2019-07-08 08:57:50 UTC - Sijie Guo: 100+ is fine. the number of subscriptions will be limited by two factors, the broker outbound bandwidth and the memory to keep the active subscriptions.
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2019-07-08 08:58:41 UTC - Dennis Sehalic: ok, and the mem footprint per subscription is low I'm guessing?
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2019-07-08 09:04:41 UTC - Sijie Guo: yes.
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2019-07-08 09:05:00 UTC - Sijie Guo: it won’t be a problem unless you have millions of subscriptions.
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2019-07-08 09:05:10 UTC - Dennis Sehalic: ok thanks man (=
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