Zyre - Local Area Clustering for Peer-to-Peer Applications

Contents

Overview

Scope and Goals

Ownership and License

Using Zyre

Building on Linux and macOS

    sudo apt-get update    sudo apt-get install -y \    git build-essential libtool \    pkg-config autotools-dev autoconf automake cmake \    uuid-dev libpcre3-dev valgrind    # only execute this next line if interested in updating the man pages as    # well (adds to build time):    sudo apt-get install -y asciidoc

    git clone --depth 1 -b stable https://github.com/jedisct1/libsodium.git    cd libsodium    ./autogen.sh && ./configure && make check    sudo make install    cd ..    git clone https://github.com/zeromq/libzmq.git    cd libzmq    ./autogen.sh    # do not specify "--with-libsodium" if you prefer to use internal tweetnacl    # security implementation (recommended for development)    ./configure --with-libsodium    make check    sudo make install    sudo ldconfig    cd ..    git clone https://github.com/zeromq/czmq.git    cd czmq    ./autogen.sh && ./configure && make check    sudo make install    sudo ldconfig    cd ..    git clone https://github.com/zeromq/zyre.git    cd zyre    ./autogen.sh && ./configure && make check    sudo make install    sudo ldconfig    cd ..

zyre/src/.libs/zyre_selftest

zyre/src/.libs/zpinger

Building on Windows

git

    git clone --depth 1 -b stable https://github.com/jedisct1/libsodium.git    git clone https://github.com/zeromq/libzmq.git    git clone https://github.com/zeromq/czmq.git    git clone https://github.com/zeromq/zyre.git    cd zyre\builds\msvc    configure.bat    cd build    buildall.bat    cd ..\..\..\..

    dir/s/b zyre_selftest.exe    zyre\builds\msvc\vs2013\DebugDEXE\zyre_selftest.exe    zyre\builds\msvc\vs2013\ReleaseDEXE\zyre_selftest.exe    :: select your choice and run it    zyre\builds\msvc\vs2013\DebugDEXE\zyre_selftest.exe

    dir/s/b zpinger.exe    zyre\builds\msvc\vs2013\DebugDEXE\zpinger.exe    zyre\builds\msvc\vs2013\ReleaseDEXE\zpinger.exe    zyre\builds\msvc\vs2013\x64\DebugDEXE\zpinger.exe    :: select your choice and run it    zyre\builds\msvc\vs2013\ReleaseDEXE\zpinger.exe

Building on Windows

git

Using CMake

git clone --depth 1 -b stable https://github.com/jedisct1/libsodium.gitcd libsodium\builds\msvc\buildbuildall.batcd ..\..\..\..

git clone https://github.com/zeromq/libzmq.gitcd libzmqmkdir buildcd buildcmake .. -DBUILD_STATIC=OFF -DBUILD_SHARED=ON -DZMQ_BUILD_TESTS=ON -DWITH_LIBSODIUM=ON -DCMAKE_INCLUDE_PATH=..\libsodium\src\libsodium\include -DCMAKE_LIBRARY_PATH=..\libsodium\bin\Win32\Release\<Platform Toolset>\dynamic -DCMAKE_INSTALL_PREFIX=C:\projects\libscmake --build . --config Release --target installcd ..\..\

git clone https://github.com/zeromq/czmq.gitcd czmqmkdir buildcd buildcmake .. -DCZMQ_BUILD_SHARED=ON -DCZMQ_BUILD_STATIC=OFF -DCMAKE_PREFIX_PATH=C:\projects\libs -DCMAKE_INSTALL_PREFIX=C:\projects\libscmake --build . --config Release --target install

git clone https://github.com/zeromq/zyre.gitcd zyremkdir buildcd buildcmake .. -DZYRE_BUILD_SHARED=ON -DZYRE_BUILD_STATIC=OFF -DCMAKE_PREFIX_PATH=C:\projects\libscmake --build . --config Releasectest -C Release

Linking with an Application

gcc myapp.c -lzyre -lczmq -lzmq -o myapp

Use from Other Languages

API Summary

zyre - API wrapping one Zyre node

ENTER fromnode name headers ipaddress:port    a new peer has entered the networkEVASIVE fromnode name    a peer is being evasive (i.e. quiet) and will be pinged manuallySILENT fromnode name    a peer has been quiet and has not answered ping after 1 secondEXIT fromnode name    a peer has left the networkJOIN fromnode name groupname    a peer has joined a specific groupLEAVE fromnode name groupname    a peer has joined a specific groupWHISPER fromnode name message    a peer has sent this node a messageSHOUT fromnode name groupname message    a peer has sent one of our groups a message

//  This is a stable class, and may not change except for emergencies. It//  is provided in stable builds.//  This class has draft methods, which may change over time. They are not//  in stable releases, by default. Use --enable-drafts to enable.//  Constructor, creates a new Zyre node. Note that until you start the//  node it is silent and invisible to other nodes on the network.//  The node name is provided to other nodes during discovery. If you//  specify NULL, Zyre generates a randomized node name from the UUID.ZYRE_EXPORTzyre_t*zyre_new (constchar*name);//  Destructor, destroys a Zyre node. When you destroy a node, any//  messages it is sending or receiving will be discarded.ZYRE_EXPORTvoidzyre_destroy (zyre_t**self_p);//  Return our node UUID string, after successful initializationZYRE_EXPORTconstchar*zyre_uuid (zyre_t*self);//  Return our node name, after successful initialization. First 6//  characters of UUID by default.ZYRE_EXPORTconstchar*zyre_name (zyre_t*self);//  Set the public name of this node overriding the default. The name is//  provide during discovery and come in each ENTER message.ZYRE_EXPORTvoidzyre_set_name (zyre_t*self,constchar*name);//  Set node header; these are provided to other nodes during discovery//  and come in each ENTER message.ZYRE_EXPORTvoidzyre_set_header (zyre_t*self,constchar*name,constchar*format, ...)CHECK_PRINTF (3);//  Set verbose mode; this tells the node to log all traffic as well as//  all major events.ZYRE_EXPORTvoidzyre_set_verbose (zyre_t*self);//  Set UDP beacon discovery port; defaults to 5670, this call overrides//  that so you can create independent clusters on the same network, for//  e.g. development vs. production. Has no effect after zyre_start().ZYRE_EXPORTvoidzyre_set_port (zyre_t*self,intport_nbr);//  Set the peer evasiveness timeout, in milliseconds. Default is 5000.//  This can be tuned in order to deal with expected network conditions//  and the response time expected by the application. This is tied to//  the beacon interval and rate of messages received.ZYRE_EXPORTvoidzyre_set_evasive_timeout (zyre_t*self,intinterval);//  Set the peer silence timeout, in milliseconds. Default is 5000.//  This can be tuned in order to deal with expected network conditions//  and the response time expected by the application. This is tied to//  the beacon interval and rate of messages received.//  Silence is triggered one second after the timeout if peer has not//  answered ping and has not sent any message.//  NB: this is currently redundant with the evasiveness timeout. Both//  affect the same timeout value.ZYRE_EXPORTvoidzyre_set_silent_timeout (zyre_t*self,intinterval);//  Set the peer expiration timeout, in milliseconds. Default is 30000.//  This can be tuned in order to deal with expected network conditions//  and the response time expected by the application. This is tied to//  the beacon interval and rate of messages received.ZYRE_EXPORTvoidzyre_set_expired_timeout (zyre_t*self,intinterval);//  Set UDP beacon discovery interval, in milliseconds. Default is instant//  beacon exploration followed by pinging every 1,000 msecs.ZYRE_EXPORTvoidzyre_set_interval (zyre_t*self,size_tinterval);//  Set network interface for UDP beacons. If you do not set this, CZMQ will//  choose an interface for you. On boxes with several interfaces you should//  specify which one you want to use, or strange things can happen.ZYRE_EXPORTvoidzyre_set_interface (zyre_t*self,constchar*value);//  By default, Zyre binds to an ephemeral TCP port and broadcasts the local//  host name using UDP beaconing. When you call this method, Zyre will use//  gossip discovery instead of UDP beaconing. You MUST set-up the gossip//  service separately using zyre_gossip_bind() and _connect(). Note that the//  endpoint MUST be valid for both bind and connect operations. You can use//  inproc://, ipc://, or tcp:// transports (for tcp://, use an IP address//  that is meaningful to remote as well as local nodes). Returns 0 if//  the bind was successful, else -1.ZYRE_EXPORTintzyre_set_endpoint (zyre_t*self,constchar*format, ...)CHECK_PRINTF (2);//  Set-up gossip discovery of other nodes. At least one node in the cluster//  must bind to a well-known gossip endpoint, so other nodes can connect to//  it. Note that gossip endpoints are completely distinct from Zyre node//  endpoints, and should not overlap (they can use the same transport).ZYRE_EXPORTvoidzyre_gossip_bind (zyre_t*self,constchar*format, ...)CHECK_PRINTF (2);//  Set-up gossip discovery of other nodes. A node may connect to multiple//  other nodes, for redundancy paths. For details of the gossip network//  design, see the CZMQ zgossip class.ZYRE_EXPORTvoidzyre_gossip_connect (zyre_t*self,constchar*format, ...)CHECK_PRINTF (2);//  Start node, after setting header values. When you start a node it//  begins discovery and connection. Returns 0 if OK, -1 if it wasn't//  possible to start the node.ZYRE_EXPORTintzyre_start (zyre_t*self);//  Stop node; this signals to other peers that this node will go away.//  This is polite; however you can also just destroy the node without//  stopping it.ZYRE_EXPORTvoidzyre_stop (zyre_t*self);//  Join a named group; after joining a group you can send messages to//  the group and all Zyre nodes in that group will receive them.ZYRE_EXPORTintzyre_join (zyre_t*self,constchar*group);//  Leave a groupZYRE_EXPORTintzyre_leave (zyre_t*self,constchar*group);//  Receive next message from network; the message may be a control//  message (ENTER, EXIT, JOIN, LEAVE) or data (WHISPER, SHOUT).//  Returns zmsg_t object, or NULL if interrupted//  Caller owns return value and must destroy it when done.ZYRE_EXPORTzmsg_t*zyre_recv (zyre_t*self);//  Send message to single peer, specified as a UUID string//  Destroys message after sendingZYRE_EXPORTintzyre_whisper (zyre_t*self,constchar*peer,zmsg_t**msg_p);//  Send message to a named group//  Destroys message after sendingZYRE_EXPORTintzyre_shout (zyre_t*self,constchar*group,zmsg_t**msg_p);//  Send formatted string to a single peer specified as UUID stringZYRE_EXPORTintzyre_whispers (zyre_t*self,constchar*peer,constchar*format, ...)CHECK_PRINTF (3);//  Send formatted string to a named groupZYRE_EXPORTintzyre_shouts (zyre_t*self,constchar*group,constchar*format, ...)CHECK_PRINTF (3);//  Return zlist of current peer ids.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTzlist_t*zyre_peers (zyre_t*self);//  Return zlist of current peers of this group.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTzlist_t*zyre_peers_by_group (zyre_t*self,constchar*name);//  Return zlist of currently joined groups.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTzlist_t*zyre_own_groups (zyre_t*self);//  Return zlist of groups known through connected peers.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTzlist_t*zyre_peer_groups (zyre_t*self);//  Return the endpoint of a connected peer.//  Returns empty string if peer does not exist.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTchar*zyre_peer_address (zyre_t*self,constchar*peer);//  Return the value of a header of a conected peer.//  Returns null if peer or key doesn't exits.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTchar*zyre_peer_header_value (zyre_t*self,constchar*peer,constchar*name);//  Return socket for talking to the Zyre node, for pollingZYRE_EXPORTzsock_t*zyre_socket (zyre_t*self);//  Print zyre node information to stdoutZYRE_EXPORTvoidzyre_print (zyre_t*self);//  Return the Zyre version for run-time API detection; returns//  major * 10000 + minor * 100 + patch, as a single integer.ZYRE_EXPORTuint64_tzyre_version (void);//  Self test of this class.ZYRE_EXPORTvoidzyre_test (boolverbose);#ifdefZYRE_BUILD_DRAFT_API//  *** Draft method, for development use, may change without warning ***//  Set the TCP port bound by the ROUTER peer-to-peer socket (beacon mode).//  Defaults to * (the port is randomly assigned by the system).//  This call overrides this, to bypass some firewall issues when ports are//  random. Has no effect after zyre_start().ZYRE_EXPORTvoidzyre_set_beacon_peer_port (zyre_t*self,intport_nbr);//  *** Draft method, for development use, may change without warning ***//  This options enables a peer to actively contest for leadership in the//  given group. If this option is not set the peer will still participate in//  elections but never gets elected. This ensures that a consent for a leader//  is reached within a group even though not every peer is contesting for//  leadership.ZYRE_EXPORTvoidzyre_set_contest_in_group (zyre_t*self,constchar*group);//  *** Draft method, for development use, may change without warning ***//  Set an alternative endpoint value when using GOSSIP ONLY. This is useful//  if you're advertising an endpoint behind a NAT.ZYRE_EXPORTvoidzyre_set_advertised_endpoint (zyre_t*self,constchar*value);//  *** Draft method, for development use, may change without warning ***//  Apply a azcert to a Zyre node.ZYRE_EXPORTvoidzyre_set_zcert (zyre_t*self,zcert_t*zcert);//  *** Draft method, for development use, may change without warning ***//  Specify the ZAP domain (for use with CURVE).ZYRE_EXPORTvoidzyre_set_zap_domain (zyre_t*self,constchar*domain);//  *** Draft method, for development use, may change without warning ***//  Set-up gossip discovery with CURVE enabled.ZYRE_EXPORTvoidzyre_gossip_connect_curve (zyre_t*self,constchar*public_key,constchar*format, ...)CHECK_PRINTF (3);//  *** Draft method, for development use, may change without warning ***//  Unpublish a GOSSIP node from local list, useful in removing nodes from list when they EXITZYRE_EXPORTvoidzyre_gossip_unpublish (zyre_t*self,constchar*node);//  *** Draft method, for development use, may change without warning ***//  Explicitly connect to a peerZYRE_EXPORTintzyre_require_peer (zyre_t*self,constchar*uuid,constchar*endpoint,constchar*public_key);#endif// ZYRE_BUILD_DRAFT_API

//  We'll use inproc gossip discovery so that this works without networkinguint64_tversion=zyre_version ();assert ((version /10000) %100==ZYRE_VERSION_MAJOR);assert ((version /100) %100==ZYRE_VERSION_MINOR);assert (version %100==ZYRE_VERSION_PATCH);//  Create two nodeszyre_t*node1=zyre_new ("node1");assert (node1);assert (streq (zyre_name (node1),"node1"));zyre_set_header (node1,"X-HELLO","World");if (verbose)zyre_set_verbose (node1);//  Set inproc endpoint for this nodeintrc=zyre_set_endpoint (node1,"inproc://zyre-node1");assert (rc==0);//  Set up gossip network for this nodezyre_gossip_bind (node1,"inproc://gossip-hub");rc=zyre_start (node1);assert (rc==0);zyre_t*node2=zyre_new ("node2");assert (node2);assert (streq (zyre_name (node2),"node2"));if (verbose)zyre_set_verbose (node2);//  Set inproc endpoint for this node//  First, try to use existing name, it'll failrc=zyre_set_endpoint (node2,"inproc://zyre-node1");assert (rc==-1);//  Now use available name and confirm that it succeedsrc=zyre_set_endpoint (node2,"inproc://zyre-node2");assert (rc==0);//  Set up gossip network for this nodezyre_gossip_connect (node2,"inproc://gossip-hub");rc=zyre_start (node2);assert (rc==0);assert (strneq (zyre_uuid (node1),zyre_uuid (node2)));zyre_join (node1,"GLOBAL");zyre_join (node2,"GLOBAL");//  Give time for them to interconnectzclock_sleep (250);if (verbose)zyre_dump (node1);zlist_t*peers=zyre_peers (node1);assert (peers);assert (zlist_size (peers)==1);zlist_destroy (&peers);zyre_join (node1,"node1 group of one");zyre_join (node2,"node2 group of one");// Give them time to join their groupszclock_sleep (250);zlist_t*own_groups=zyre_own_groups (node1);assert (own_groups);assert (zlist_size (own_groups)==2);zlist_destroy (&own_groups);zlist_t*peer_groups=zyre_peer_groups (node1);assert (peer_groups);assert (zlist_size (peer_groups)==2);zlist_destroy (&peer_groups);char*value=zyre_peer_header_value (node2,zyre_uuid (node1),"X-HELLO");assert (streq (value,"World"));zstr_free (&value);//  One node shouts to GLOBALzyre_shouts (node1,"GLOBAL","Hello, World");//  Second node should receive ENTER, JOIN, and SHOUTzmsg_t*msg=zyre_recv (node2);assert (msg);char*command=zmsg_popstr (msg);assert (streq (command,"ENTER"));zstr_free (&command);assert (zmsg_size (msg)==4);char*peerid=zmsg_popstr (msg);char*name=zmsg_popstr (msg);assert (streq (name,"node1"));zstr_free (&name);zframe_t*headers_packed=zmsg_pop (msg);char*address=zmsg_popstr (msg);char*endpoint=zyre_peer_address (node2,peerid);assert (streq (address,endpoint));zstr_free (&peerid);zstr_free (&endpoint);zstr_free (&address);assert (headers_packed);zhash_t*headers=zhash_unpack (headers_packed);assert (headers);zframe_destroy (&headers_packed);assert (streq ((char*)zhash_lookup (headers,"X-HELLO"),"World"));zhash_destroy (&headers);zmsg_destroy (&msg);msg=zyre_recv (node2);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"JOIN"));zstr_free (&command);assert (zmsg_size (msg)==3);zmsg_destroy (&msg);msg=zyre_recv (node2);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"JOIN"));zstr_free (&command);assert (zmsg_size (msg)==3);zmsg_destroy (&msg);msg=zyre_recv (node2);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"SHOUT"));zstr_free (&command);zmsg_destroy (&msg);zyre_stop (node2);msg=zyre_recv (node2);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"STOP"));zstr_free (&command);zmsg_destroy (&msg);zyre_stop (node1);zyre_destroy (&node1);zyre_destroy (&node2);printf ("OK\n");#ifdefZYRE_BUILD_DRAFT_API//  DRAFT-API: Securityif (zsys_has_curve()){printf (" * zyre-curve: ");if (verbose)printf ("\n");if (verbose)zsys_debug("----------------TESTING CURVE --------------");zactor_t*speaker=zactor_new (zbeacon,NULL);assert (speaker);if (verbose)zstr_sendx (speaker,"VERBOSE",NULL);// ensuring we have a broadcast addresszsock_send (speaker,"si","CONFIGURE",9999);char*hostname=zstr_recv (speaker);if (!*hostname) {printf ("OK (skipping test, no UDP broadcasting)\n");zactor_destroy (&speaker);freen (hostname);return;        }freen (hostname);zactor_destroy (&speaker);// zap setupzactor_t*auth=zactor_new(zauth,NULL);assert (auth);if (verbose) {zstr_sendx(auth,"VERBOSE",NULL);zsock_wait(auth);        }zstr_sendx (auth,"CURVE",CURVE_ALLOW_ANY,NULL);zsock_wait (auth);zyre_t*node3=zyre_new ("node3");zyre_t*node4=zyre_new ("node4");assert (node3);assert (node4);if (verbose) {zyre_set_verbose (node3);zyre_set_verbose (node4);        }zyre_set_zap_domain(node3,"TEST");zyre_set_zap_domain(node4,"TEST");zsock_set_rcvtimeo(node3->inbox,10000);zsock_set_rcvtimeo(node4->inbox,10000);zcert_t*node3_cert=zcert_new ();zcert_t*node4_cert=zcert_new ();assert (node3_cert);assert (node4_cert);zyre_set_zcert (node3,node3_cert);zyre_set_zcert (node4,node4_cert);zyre_set_header (node3,"X-PUBLICKEY","%s",zcert_public_txt (node3_cert));zyre_set_header (node4,"X-PUBLICKEY","%s",zcert_public_txt (node4_cert));// test beaconif (verbose)zsys_debug ("----------------TESTING BEACON----------------");rc=zyre_start (node3);assert (rc==0);rc=zyre_start (node4);assert (rc==0);zyre_join (node3,"GLOBAL");zyre_join (node4,"GLOBAL");zclock_sleep (1500);if (verbose) {zyre_dump (node3);zyre_dump (node4);        }zyre_shouts (node3,"GLOBAL","Hello, World");//  Second node should receive ENTER, JOIN, and SHOUTmsg=zyre_recv (node4);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"ENTER"));zstr_free (&command);char*peerid=zmsg_popstr (msg);assert (peerid);name=zmsg_popstr (msg);assert (streq (name,"node3"));zmsg_destroy (&msg);msg=zyre_recv (node4);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"JOIN"));zstr_free (&command);zmsg_destroy (&msg);msg=zyre_recv (node4);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"SHOUT"));zstr_free (&command);zmsg_destroy (&msg);zyre_leave (node3,"GLOBAL");zyre_leave (node4,"GLOBAL");zstr_free (&name);zstr_free (&peerid);zstr_free (&command);zyre_stop (node3);zyre_stop (node4);// give things a chance to settle...zclock_sleep (250);zyre_destroy(&node3);zyre_destroy(&node4);zcert_destroy(&node3_cert);zcert_destroy(&node4_cert);// test gossipif (verbose)zsys_debug ("----------------TESTING GOSSIP----------------");zyre_t*node5=zyre_new ("node5");zyre_t*node6=zyre_new ("node6");assert (node5);assert (node6);if (verbose) {zyre_set_verbose (node5);zyre_set_verbose (node6);        }// if it takes more than 10s, something probably went terribly wrongzsock_set_rcvtimeo(node5->inbox,10000);zsock_set_rcvtimeo(node6->inbox,10000);zcert_t*node5_cert=zcert_new ();zcert_t*node6_cert=zcert_new ();assert (node5_cert);assert (node6_cert);zyre_set_zcert(node5,node5_cert);zyre_set_zcert(node6,node6_cert);zyre_set_header(node5,"X-PUBLICKEY","%s",zcert_public_txt(node5_cert));zyre_set_header(node6,"X-PUBLICKEY","%s",zcert_public_txt(node6_cert));// TODO- set_advertised_endpoint tests//        zyre_set_endpoint(node5, "tcp://127.0.0.1:9001");//        zyre_set_advertised_endpoint(node5, "tcp://localhost:9001");constchar*gossip_cert=zcert_public_txt (node5_cert);// TODO- need to add zyre_gossip_port functions to get port from gossip bind(?)zyre_gossip_bind(node5,"tcp://127.0.0.1:9001");zyre_gossip_connect_curve(node6,gossip_cert,"tcp://127.0.0.1:9001");rc=zyre_start (node5);assert (rc==0);rc=zyre_start (node6);assert (rc==0);zyre_join (node5,"GLOBAL");zyre_join (node6,"GLOBAL");// give things a chance to settle...zclock_sleep (1500);if (verbose) {zyre_dump (node5);zyre_dump (node6);        }zyre_shouts (node5,"GLOBAL","Hello, World");//  Second node should receive ENTER, JOIN, and SHOUTmsg=zyre_recv (node6);assert (msg);command=zmsg_popstr (msg);assert (streq (command,"ENTER"));zstr_free (&command);peerid=zmsg_popstr (msg);assert (peerid);name=zmsg_popstr (msg);zmsg_destroy (&msg);assert (streq (name,"node5"));zstr_free (&name);zyre_leave (node5,"GLOBAL");zyre_leave (node6,"GLOBAL");zyre_stop (node5);zyre_stop (node6);// give things a chance to settle...zclock_sleep (250);zstr_free (&peerid);zcert_destroy (&node5_cert);zcert_destroy (&node6_cert);zyre_destroy (&node5);zyre_destroy (&node6);zactor_destroy (&auth);printf ("OK\n");        }#endif    }

zyre_event - no title found

//  This is a stable class, and may not change except for emergencies. It//  is provided in stable builds.//  Constructor: receive an event from the zyre node, wraps zyre_recv.//  The event may be a control message (ENTER, EXIT, JOIN, LEAVE) or//  data (WHISPER, SHOUT).ZYRE_EXPORTzyre_event_t*zyre_event_new (zyre_t*node);//  Destructor; destroys an event instanceZYRE_EXPORTvoidzyre_event_destroy (zyre_event_t**self_p);//  Returns event type, as printable uppercase string. Choices are://  "ENTER", "EXIT", "JOIN", "LEAVE", "EVASIVE", "WHISPER" and "SHOUT"//  and for the local node: "STOP"ZYRE_EXPORTconstchar*zyre_event_type (zyre_event_t*self);//  Return the sending peer's uuid as a stringZYRE_EXPORTconstchar*zyre_event_peer_uuid (zyre_event_t*self);//  Return the sending peer's public name as a stringZYRE_EXPORTconstchar*zyre_event_peer_name (zyre_event_t*self);//  Return the sending peer's ipaddress as a stringZYRE_EXPORTconstchar*zyre_event_peer_addr (zyre_event_t*self);//  Returns the event headers, or NULL if there are noneZYRE_EXPORTzhash_t*zyre_event_headers (zyre_event_t*self);//  Returns value of a header from the message headers//  obtained by ENTER. Return NULL if no value was found.ZYRE_EXPORTconstchar*zyre_event_header (zyre_event_t*self,constchar*name);//  Returns the group name that a SHOUT event was sent toZYRE_EXPORTconstchar*zyre_event_group (zyre_event_t*self);//  Returns the incoming message payload; the caller can modify the//  message but does not own it and should not destroy it.ZYRE_EXPORTzmsg_t*zyre_event_msg (zyre_event_t*self);//  Returns the incoming message payload, and pass ownership to the//  caller. The caller must destroy the message when finished with it.//  After called on the given event, further calls will return NULL.//  Caller owns return value and must destroy it when done.ZYRE_EXPORTzmsg_t*zyre_event_get_msg (zyre_event_t*self);//  Print event to zsys logZYRE_EXPORTvoidzyre_event_print (zyre_event_t*self);//  Self test of this class.ZYRE_EXPORTvoidzyre_event_test (boolverbose);

//  Create two nodeszyre_t*node1=zyre_new ("node1");assert (node1);zyre_set_header (node1,"X-HELLO","World");intrc=zyre_set_endpoint (node1,"inproc://zyre-node1");assert (rc==0);// use gossiping instead of beaconing, suits Travis betterzyre_gossip_bind (node1,"inproc://gossip-hub");if (verbose)zyre_set_verbose (node1);if (zyre_start (node1)) {zyre_destroy (&node1);printf ("OK (skipping test, no UDP discovery)\n");return;    }zyre_join (node1,"GLOBAL");zyre_t*node2=zyre_new ("node2");assert (node2);if (verbose)zyre_set_verbose (node2);rc=zyre_set_endpoint (node2,"inproc://zyre-node2");assert (rc==0);// use gossiping instead of beaconing, suits Travis betterzyre_gossip_connect (node2,"inproc://gossip-hub");rc=zyre_start (node2);assert (rc==0);zyre_join (node2,"GLOBAL");//  Give time for them to interconnectzclock_sleep (250);//  One node shouts to GLOBALzmsg_t*msg=zmsg_new ();zmsg_addstr (msg,"Hello, World");zyre_shout (node1,"GLOBAL",&msg);zclock_sleep (100);//  Parse ENTERzyre_event_t*event=zyre_event_new (node2);assert (streq (zyre_event_type (event),"ENTER"));constchar*sender=zyre_event_peer_uuid (event);assert (sender);constchar*name=zyre_event_peer_name (event);assert (name);assert (streq (name,"node1"));constchar*address=zyre_event_peer_addr (event);assert (address);constchar*header=zyre_event_header (event,"X-HELLO");assert (header);zyre_event_destroy (&event);//  Parse JOIN//  We tolerate other events, which we can get if there are instances//  of Zyre running somewhere on the network.event=zyre_event_new (node2);if (streq (zyre_event_type (event),"JOIN")) {//  Parse SHOUTzyre_event_destroy (&event);event=zyre_event_new (node2);if (streq (zyre_event_type (event),"SHOUT")) {assert (streq (zyre_event_group (event),"GLOBAL"));zmsg_t*msg=zyre_event_get_msg (event);char*string=zmsg_popstr (msg);zmsg_destroy (&msg);assert (streq (string,"Hello, World"));free (string);        }zyre_event_destroy (&event);    }zyre_destroy (&node1);zyre_destroy (&node2);

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