24 skills found
PiotrJustyna / Road To OrleansThis repository illustrates the road to orleans with practical, real-life examples. From most basic, to more advanced techniques.
VincentH-Net / Orleans.MultitenantSecure, flexible tenant separation for Microsoft Orleans
VincentH-Net / Orleans.MultiservicePrevent microservices pain with logical service separation in a modular monolith for Microsoft Orleans 9
OrleansContrib / Orleans.SyncWorkThis package's intention is to expose an abstract base class to allow https://github.com/dotnet/orleans/ to work with long running CPU bound synchronous work, without becoming overloaded.
Kritner-Blogs / OrleansGettingStartedRepository for blog posts pertaining to Orleans "Getting Started"
VincentH-Net / Orleans.ResultsConcise, version-tolerant result pattern implementation for Microsoft Orleans 8
SOYJUN / Implement ODR ProtocolOverview For this assignment you will be developing and implementing : An On-Demand shortest-hop Routing (ODR) protocol for networks of fixed but arbitrary and unknown connectivity, using PF_PACKET sockets. The implementation is based on (a simplified version of) the AODV algorithm. Time client and server applications that send requests and replies to each other across the network using ODR. An API you will implement using Unix domain datagram sockets enables applications to communicate with the ODR mechanism running locally at their nodes. I shall be discussing the assignment in class on Wednesday, October 29, and Monday, November 3. The following should prove useful reference material for the assignment : Sections 15.1, 15.2, 15.4 & 15.6, Chapter 15, on Unix domain datagram sockets. PF_PACKET(7) from the Linux manual pages. You might find these notes made by a past CSE 533 student useful. Also, the following link http://www.pdbuchan.com/rawsock/rawsock.html contains useful code samples that use PF_PACKET sockets (as well as other code samples that use raw IP sockets which you do not need for this assignment, though you will be using these types of sockets for Assignment 4). Charles E. Perkins & Elizabeth M. Royer. “Ad-hoc On-Demand Distance Vector Routing.” Proceedings of the 2nd IEEE Workshop on Mobile Computing Systems and Applications, New Orleans, Louisiana, February 1999, pp. 90 - 100. The VMware environment minix.cs.stonybrook.edu is a Linux box running VMware. A cluster of ten Linux virtual machines, called vm1 through vm10, on which you can gain access as root and run your code have been created on minix. See VMware Environment Hosts for further details. VMware instructions takes you to a page that explains how to use the system. The ten virtual machines have been configured into a small virtual intranet of Ethernet LANs whose topology is (in principle) unknown to you. There is a course account cse533 on node minix, with home directory /users/cse533. In there, you will find a subdirectory Stevens/unpv13e , exactly as you are used to having on the cs system. You should develop your source code and makefiles for handing in accordingly. You will be handing in your source code on the minix node. Note that you do not need to link against the socket library (-lsocket) in Linux. The same is true for -lnsl and -lresolv. For example, take a look at how the LIBS variable is defined for Solaris, in /home/courses/cse533/Stevens/unpv13e_solaris2.10/Make.defines (on compserv1, say) : LIBS = ../libunp.a -lresolv -lsocket -lnsl -lpthread But if you take a look at Make.defines on minix (/users/cse533/Stevens/unpv13e/Make.defines) you will find only: LIBS = ../libunp.a -lpthread The nodes vm1 , . . . . . , vm10 are all multihomed : each has two (or more) interfaces. The interface ‘eth0 ’ should be completely ignored and is not to be used for this assignment (because it shows all ten nodes as if belonging to the same single Ethernet 192.168.1.0/24, rather than to an intranet composed of several Ethernets). Note that vm1 , . . . . . , vm10 are virtual machines, not real ones. One implication of this is that you will not be able to find out what their (virtual) IP addresses are by using nslookup and such. To find out these IP addresses, you need to look at the file /etc/hosts on minix. More to the point, invoking gethostbyname for a given vm will return to you only the (primary) IP address associated with the interface eth0 of that vm (which is the interface you will not be using). It will not return to you any other IP address for the node. Similarly, gethostbyaddr will return the vm node name only if you give it the (primary) IP address associated with the interface eth0 for the node. It will return nothing if you give it any other IP address for the node, even though the address is perfectly valid. Because of this, and because it will ease your task to be able to use gethostbyname and gethostbyaddr in a straightforward way, we shall adopt the (primary) IP addresses associated with interfaces eth0 as the ‘canonical’ IP addresses for the nodes (more on this below). Time client and server A time server runs on each of the ten vm machines. The client code should also be available on each vm so that it can be evoked at any of them. Normally, time clients/servers exchange request/reply messages using the TCP/UDP socket API that, effectively, enables them to receive service (indirectly, via the transport layer) from the local IP mechanism running at their nodes. You are to implement an API using Unix domain sockets to access the local ODR service directly (somewhat similar, in effect, to the way that raw sockets permit an application to access IP directly). Use Unix domain SOCK_DGRAM, rather than SOCK_STREAM, sockets (see Figures 15.5 & 15.6, pp. 418 - 419). API You need to implement a msg_send function that will be called by clients/servers to send requests/replies. The parameters of the function consist of : int giving the socket descriptor for write char* giving the ‘canonical’ IP address for the destination node, in presentation format int giving the destination ‘port’ number char* giving message to be sent int flag if set, force a route rediscovery to the destination node even if a non-‘stale’ route already exists (see below) msg_send will format these parameters into a single char sequence which is written to the Unix domain socket that a client/server process creates. The sequence will be read by the local ODR from a Unix domain socket that the ODR process creates for itself. Recall that the ‘canonical’ IP address for a vm node is the (primary) IP address associated with the eth0 interface for the node. It is what will be returned to you by a call to gethostbyname. Similarly, we need a msg_recv function which will do a (blocking) read on the application domain socket and return with : int giving socket descriptor for read char* giving message received char* giving ‘canonical’ IP address for the source node of message, in presentation format int* giving source ‘port’ number This information is written as a single char sequence by the ODR process to the domain socket that it creates for itself. It is read by msg_recv from the domain socket the client/server process creates, decomposed into the three components above, and returned to the caller of msg_recv. Also see the section below entitled ODR and the API. Client When a client is evoked at a node, it creates a domain datagram socket. The client should bind its socket to a ‘temporary’ (i.e., not ‘well-known’) sun_path name obtained from a call to tmpnam() (cf. line 10, Figure 15.6, p. 419) so that multiple clients may run at the same node. Note that tmpnam() is actually highly deprecated. You should use the mkstemp() function instead - look up the online man pages on minix (‘man mkstemp’) for details. As you run client code again and again during the development stage, the temporary files created by the calls to tmpnam / mkstemp start to proliferate since these files are not automatically removed when the client code terminates. You need to explicitly remove the file created by the client evocation by issuing a call to unlink() or to remove() in your client code just before the client code exits. See the online man pages on minix (‘man unlink’, ‘man remove’) for details. The client then enters an infinite loop repeating the steps below. The client prompts the user to choose one of vm1 , . . . . . , vm10 as a server node. Client msg_sends a 1 or 2 byte message to server and prints out on stdout the message client at node vm i1 sending request to server at vm i2 (In general, throughout this assignment, “trace” messages such as the one above should give the vm names and not IP addresses of the nodes.) Client then blocks in msg_recv awaiting response. This attempt to read from the domain socket should be backed up by a timeout in case no response ever comes. I leave it up to you whether you ‘wrap’ the call to msg_recv in a timeout, or you implement the timeout inside msg_recv itself. When the client receives a response it prints out on stdout the message client at node vm i1 : received from vm i2 <timestamp> If, on the other hand, the client times out, it should print out the message client at node vm i1 : timeout on response from vm i2 The client then retransmits the message out, setting the flag parameter in msg_send to force a route rediscovery, and prints out an appropriate message on stdout. This is done only once, when a timeout for a given message to the server occurs for the first time. Client repeats steps 1. - 3. Server The server creates a domain datagram socket. The server socket is assumed to have a (node-local) ‘well-known’ sun_path name which it binds to. This ‘well-known’ sun_path name is designated by a (network-wide) ‘well-known’ ‘port’ value. The time client uses this ‘port’ value to communicate with the server. The server enters an infinite sequence of calls to msg_recv followed by msg_send, awaiting client requests and responding to them. When it responds to a client request, it prints out on stdout the message server at node vm i1 responding to request from vm i2 ODR The ODR process runs on each of the ten vm machines. It is evoked with a single command line argument which gives a “staleness” time parameter, in seconds. It uses get_hw_addrs (available to you on minix in ~cse533/Asgn3_code) to obtain the index, and associated (unicast) IP and Ethernet addresses for each of the node’s interfaces, except for the eth0 and lo (loopback) interfaces, which should be ignored. In the subdirectory ~cse533/Asgn3_code (/users/cse533/Asgn3_code) on minix I am providing you with two functions, get_hw_addrs and prhwaddrs. These are analogous to the get_ifi_info_plus and prifinfo_plus of Assignment 2. Like get_ifi_info_plus, get_hw_addrs uses ioctl. get_hw_addrs gets the (primary) IP address, alias IP addresses (if any), HW address, and interface name and index value for each of the node's interfaces (including the loopback interface lo). prhwaddrs prints that information out. You should modify and use these functions as needed. Note that if an interface has no HW address associated with it (this is, typically, the case for the loopback interface lo for example), then ioctl returns get_hw_addrs a HW address which is the equivalent of 00:00:00:00:00:00 . get_hw_addrs stores this in the appropriate field of its data structures as it would with any HW address returned by ioctl, but when prhwaddrs comes across such an address, it prints a blank line instead of its usual ‘HWaddr = xx:xx:xx:xx:xx:xx’. The ODR process creates one or more PF_PACKET sockets. You will need to try out PF_PACKET sockets for yourselves and familiarize yourselves with how they behave. If, when you read from the socket and provide a sockaddr_ll structure, the kernel returns to you the index of the interface on which the incoming frame was received, then one socket will be enough. Otherwise, somewhat in the manner of Assignment 2, you shall have to create a PF_PACKET socket for every interface of interest (which are all the interfaces of the node, excluding interfaces lo and eth0 ), and bind a socket to each interface. Furthermore, if the kernel also returns to you the source Ethernet address of the frame in the sockaddr_ll structure, then you can make do with SOCK_DGRAM type PF_PACKET sockets; otherwise you shall have to use SOCK_RAW type sockets (although I would prefer you to use SOCK_RAW type sockets anyway, even if it turns out you can make do with SOCK_DGRAM type). The socket(s) should have a protocol value (no larger than 0xffff so that it fits in two bytes; this value is given as a network-byte-order parameter in the call(s) to function socket) that identifies your ODR protocol. The <linux/if_ether.h> include file (i.e., the file /usr/include/linux/if_ether.h) contains protocol values defined for the standard protocols typically found on an Ethernet LAN, as well as other values such as ETH_P_ALL. You should set protocol to a value of your choice which is not a <linux/if_ether.h> value, but which is, hopefully, unique to yourself. Remember that you will all be running your code using the same root account on the vm1 , . . . . . , vm10 nodes. So if two of you happen to choose the same protocol value and happen to be running on the same vm node at the same time, your applications will receive each other’s frames. For that reason, try to choose a protocol value for the socket(s) that is likely to be unique to yourself (something based on your Stony Brook student ID number, for example). This value effectively becomes the protocol value for your implementation of ODR, as opposed to some other cse 533 student's implementation. Because your value of protocol is to be carried in the frame type field of the Ethernet frame header, the value chosen should be not less than 1536 (0x600) so that it is not misinterpreted as the length of an Ethernet 802.3 frame. Note from the man pages for packet(7) that frames are passed to and from the socket without any processing in the frame content by the device driver on the other side of the socket, except for calculating and tagging on the 4-byte CRC trailer for outgoing frames, and stripping that trailer before delivering incoming frames to the socket. Nevertheless, if you write a frame that is less than 60 bytes, the necessary padding is automatically added by the device driver so that the frame that is actually transmitted out is the minimum Ethernet size of 64 bytes. When reading from the socket, however, any such padding that was introduced into a short frame at the sending node to bring it up to the minimum frame size is not stripped off - it is included in what you receive from the socket (thus, the minimum number of bytes you receive should never be less than 60). Also, you will have to build the frame header for outgoing frames yourselves (assuming you use SOCK_RAW type sockets). Bear in mind that the field values in that header have to be in network order. The ODR process also creates a domain datagram socket for communication with application processes at the node, and binds the socket to a ‘well known’ sun_path name for the ODR service. Because it is dealing with fixed topologies, ODR is, by and large, considerably simpler than AODV. In particular, discovered routes are relatively stable and there is no need for all the paraphernalia that goes with the possibility of routes changing (such as maintenance of active nodes in the routing tables and timeout mechanisms; timeouts on reverse links; lifetime field in the RREP messages; etc.) Nor will we be implementing source_sequence_#s (in the RREQ messages), and dest_sequence_# (in RREQ and RREP messages). In reality, we should (though we will not, for the sake of simplicity, be doing so) implement some sort of sequence number mechanism, or some alternative mechanism such as split-horizon for example, if we are to avoid possible scenarios of routing loops in a “count to infinity” context (I shall explain this point in class). However, we want ODR to discover shortest-hop paths, and we want it to do so in a reasonably efficient manner. This necessitates having one or two aspects of its operations work in a different, possibly slightly more complicated, way than AODV does. ODR has several basic responsibilities : Build and maintain a routing table. For each destination in the table, the routing table structure should include, at a minimum, the next-hop node (in the form of the Ethernet address for that node) and outgoing interface index, the number of hops to the destination, and a timestamp of when the the routing table entry was made or last “reconfirmed” / updated. Note that a destination node in the table is to be identified only by its ‘canonical’ IP address, and not by any other IP addresses the node has. Generate a RREQ in response to a time client calling msg_send for a destination for which ODR has no route (or for which a route exists, but msg_send has the flag parameter set or the route has gone ‘stale’ – see below), and ‘flood’ the RREQ out on all the node’s interfaces (except for the interface it came in on and, of course, the interfaces eth0 and lo). Flooding is done using an Ethernet broadcast destination address (0xff:ff:ff:ff:ff:ff) in the outgoing frame header. Note that a copy of the broadcast packet is supposed to / might be looped back to the node that sends it (see p. 535 in the Stevens textbook). ODR will have to take care not to treat these copies as new incoming RREQs. Also note that ODR at the client node increments the broadcast_id every time it issues a new RREQ for any destination node. When a RREQ is received, ODR has to generate a RREP if it is at the destination node, or if it is at an intermediate node that happens to have a route (which is not ‘stale’ – see below) to the destination. Otherwise, it must propagate the RREQ by flooding it out on all the node’s interfaces (except the interface the RREQ arrived on). Note that as it processes received RREQs, ODR should enter the ‘reverse’ route back to the source node into its routing table, or update an existing entry back to the source node if the RREQ received shows a shorter-hop route, or a route with the same number of hops but going through a different neighbour. The timestamp associated with the table entry should be updated whenever an existing route is either “reconfirmed” or updated. Obviously, if the node is going to generate a RREP, updating an existing entry back to the source node with a more efficient route, or a same-hops route using a different neighbour, should be done before the RREP is generated. Unlike AODV, when an intermediate node receives a RREQ for which it generates a RREP, it should nevertheless continue to flood the RREQ it received if the RREQ pertains to a source node whose existence it has heretofore been unaware of, or the RREQ gives it a more efficient route than it knew of back to the source node (the reason for continuing to flood the RREQ is so that other nodes in the intranet also become aware of the existence of the source node or of the potentially more optimal reverse route to it, and update their tables accordingly). However, since an RREP for this RREQ is being sent by our node, we do not want other nodes who receive the RREQ propagated by our node, and who might be in a position to do so, to also send RREPs. So we need to introduce a field in the RREQ message, not present in the AODV specifications, which acts like a “RREP already sent” field. Our node sets this field before further propagating the RREQ and nodes receiving an RREQ with this field set do not send RREPs in response, even if they are in a position to do so. ODR may, of course, receive multiple, distinct instances of the same RREQ (the combination of source_addr and broadcast_id uniquely identifies the RREQ). Such RREQs should not be flooded out unless they have a lower hop count than instances of that RREQ that had previously been received. By the same token, if ODR is in a position to send out a RREP, and has already done so for this, now repeating, RREQ , it should not send out another RREP unless the RREQ shows a more efficient, previously unknown, reverse route back to the source node. In other words, ODR should not generate essentially duplicative RREPs, nor generate RREPs to instances of RREQs that reflect reverse routes to the source that are not more efficient than what we already have. Relay RREPs received back to the source node (this is done using the ‘reverse’ route entered into the routing table when the corresponding RREQ was processed). At the same time, a ‘forward’ path to the destination is entered into the routing table. ODR could receive multiple, distinct RREPs for the same RREQ. The ‘forward’ route entered in the routing table should be updated to reflect the shortest-hop route to the destination, and RREPs reflecting suboptimal routes should not be relayed back to the source. In general, maintaining a route and its associated timestamp in the table in response to RREPs received is done in the same manner described above for RREQs. Forward time client/server messages along the next hop. (The following is important – you will lose points if you do not implement it.) Note that such application payload messages (especially if they are the initial request from the client to the server, rather than the server response back to the client) can be like “free” RREPs, enabling nodes along the path from source (client) to destination (server) node to build a reverse path back to the client node whose existence they were heretofore unaware of (or, possibly, to update an existing route with a more optimal one). Before it forwards an application payload message along the next hop, ODR at an intermediate node (and also at the final destination node) should use the message to update its routing table in this way. Thus, calls to msg_send by time servers should never cause ODR at the server node to initiate RREQs, since the receipt of a time client request implies that a route back to the client node should now exist in the routing table. The only exception to this is if the server node has a staleness parameter of zero (see below). A routing table entry has associated with it a timestamp that gives the time the entry was made into the table. When a client at a node calls msg_send, and if an entry for the destination node already exists in the routing table, ODR first checks that the routing information is not ‘stale’. A stale routing table entry is one that is older than the value defined by the staleness parameter given as a command line argument to the ODR process when it is executed. ODR deletes stale entries (as well as non-stale entries when the flag parameter in msg_send is set) and initiates a route rediscovery by issuing a RREQ for the destination node. This will force periodic updating of the routing tables to take care of failed nodes along the current path, Ethernet addresses that might have changed, and so on. Similarly, as RREQs propagate through the intranet, existing stale table entries at intermediate nodes are deleted and new route discoveries propagated. As noted above when discussing the processing of RREQs and RREPs, the associated timestamp for an existing table entry is updated in response to having the route either “reconfirmed” or updated (this applies to both reverse routes, by virtue of RREQs received, and to forward routes, by virtue of RREPs). Finally, note that a staleness parameter of 0 essentially indicates that the discovered route will be used only once, when first discovered, and then discarded. Effectively, an ODR with staleness parameter 0 maintains no real routing table at all ; instead, it forces route discoveries at every step of its operation. As a practical matter, ODR should be run with staleness parameter values that are considerably larger than the longest RTT on the intranet, otherwise performance will degrade considerably (and collapse entirely as the parameter values approach 0). Nevertheless, for robustness, we need to implement a mechanism by which an intermediate node that receives a RREP or application payload message for forwarding and finds that its relevant routing table entry has since gone stale, can intiate a RREQ to rediscover the route it needs. RREQ, RREP, and time client/server request/response messages will all have to be carried as encapsulated ODR protocol messages that form the data payload of Ethernet frames. So we need to design the structure of ODR protocol messages. The format should contain a type field (0 for RREQ, 1 for RREP, 2 for application payload ). The remaining fields in an ODR message will depend on what type it is. The fields needed for (our simplified versions of AODV’s) RREQ and RREP should be fairly clear to you, but keep in mind that you need to introduce two extra fields: The “RREP already sent” bit or field in RREQ messages, as mentioned above. A “forced discovery” bit or field in both RREQ and RREP messages: When a client application forces route rediscovery, this bit should be set in the RREQ issued by the client node ODR. Intermediate nodes that are not the destination node but which do have a route to the destination node should not respond with RREPs to an RREQ which has the forced discovery field set. Instead, they should continue to flood the RREQ so that it eventually reaches the destination node which will then respond with an RREP. The intermediate nodes relaying such an RREQ must update their ‘reverse’ route back to the source node accordingly, even if the new route is less efficient (i.e., has more hops) than the one they currently have in their routing table. The destination node responds to the RREQ with an RREP in which this field is also set. Intermediate nodes that receive such a forced discovery RREP must update their ‘forward’ route to the destination node accordingly, even if the new route is less efficient (i.e., has more hops) than the one they currently have in their routing table. This behaviour will cause a forced discovery RREQ to be responded to only by the destination node itself and not any other node, and will cause intermediate nodes to update their routing tables to both source and destination nodes in accordance with the latest routing information received, to cover the possibility that older routes are no longer valid because nodes and/or links along their paths have gone down. A type 2, application payload, message needs to contain the following type of information : type = 2 ‘canonical’ IP address of source node ‘port’ number of source application process (This, of course, is not a real port number in the TCP/UDP sense, but simply a value that ODR at the source node uses to designate the sun_path name for the source application’s domain socket.) ‘canonical’ IP address of destination node ‘port’ number of destination application process (This is passed to ODR by the application process at the source node when it calls msg_send. Its designates the sun_path name for an application’s domain socket at the destination node.) hop count (This starts at 0 and is incremented by 1 at each hop so that ODR can make use of the message to update its routing table, as discussed above.) number of bytes in application message The fields above essentially constitute a ‘header’ for the ODR message. Note that fields which you choose to have carry numeric values (rather than ascii characters, for example) must be in network byte order. ODR-defined numeric-valued fields in type 0, RREQ, and type 1, RREP, messages must, of course, also be in network byte order. Also note that only the ‘canonical’ IP addresses are used for the source and destination nodes in the ODR header. The same has to be true in the headers for type 0, RREQ, and type 1, RREP, messages. The general rule is that ODR messages only carry ‘canonical’ IP node addresses. The last field in the type 2 ODR message is essentially the data payload of the message. application message given in the call to msg_send An ODR protocol message is encapsulated as the data payload of an Ethernet frame whose header it fills in as follows : source address = Ethernet address of outgoing interface of the current node where ODR is processing the message. destination address = Ethernet broadcast address for type 0 messages; Ethernet address of next hop node for type 1 & 2 messages. protocol field = protocol value for the ODR PF_PACKET socket(s). Last but not least, whenever ODR writes an Ethernet frame out through its socket, it prints out on stdout the message ODR at node vm i1 : sending frame hdr src vm i1 dest addr ODR msg type n src vm i2 dest vm i3 where addr is in presentation format (i.e., hexadecimal xx:xx:xx:xx:xx:xx) and gives the destination Ethernet address in the outgoing frame header. Other nodes in the message should be identified by their vm name. A message should be printed out for each packet sent out on a distinct interface. ODR and the API When the ODR process first starts, it must construct a table in which it enters all well-known ‘port’ numbers and their corresponding sun_path names. These will constitute permanent entries in the table. Thereafter, whenever it reads a message off its domain socket, it must obtain the sun_path name for the peer process socket and check whether that name is entered in the table. If not, it must select an ‘ephemeral’ ‘port’ value by which to designate the peer sun_path name and enter the pair < port value , sun_path name > into the table. Such entries cannot be permanent otherwise the table will grow unboundedly in time, with entries surviving for ever, beyond the peer processes’ demise. We must associate a time_to_live field with a non-permanent table entry, and purge the entry if nothing is heard from the peer for that amount of time. Every time a peer process for which a non-permanent table entry exists communicates with ODR, its time_to_live value should be reinitialized. Note that when ODR writes to a peer, it is possible for the write to fail because the peer does not exist : it could be a ‘well-known’ service that is not running, or we could be in the interval between a process with a non-permanent table entry terminating and the expiration of its time_to_live value. Notes A proper implementation of ODR would probably require that RREQ and RREP messages be backed up by some kind of timeout and retransmission mechanism since the network transmission environment is not reliable. This would considerably complicate the implementation (because at any given moment, a node could have multiple RREQs that it has flooded out, but for which it has still not received RREPs; the situation is further complicated by the fact that not all intermediate nodes receiving and relaying RREQs necessarily lie on a path to the destination, and therefore should expect to receive RREPs), and, learning-wise, would not add much to the experience you should have gained from Assignment 2.
richorama / Orleans IoT ExampleAm extremely basic sample application to demonstrate how Project Orleans could be used in an 'Internet of Things' scenario.
OrleansContrib / OrleansShardedStorageA library and test application to shard Orleans grains across multiple Azure Storage Accounts
mikuam / Orleans Core ExampleAn example project of Microsoft Orleans on .Net Core with receiving and sending Service Bus messages and persistent grain state with Cosmos Table Api.
creyke / ToasterServiceAn example of embedding an Orleans silo in the same process as an ASP.NET Web API
Azure-Samples / Build Your First Orleans App AspnetcoreThe example project for the "Build your first Orleans app with ASP.NET Core 6.0" learn module.
rallets / Orleans Angular AspnetcoreAn example project with Microsoft Orleans, Angular and ASP.NET Core
GranDen-Corp / GameLeaderboardDemoDemo using Microsoft Orleans to build a real-time game leaderboard example
chgeuer / Orleans.ParcelTrackerNo description available
ledjon-behluli / Orleans.BalancedResourcePlacementA placement strategy which attempts to achieve approximately even load based on cluster resources.
Neftedollar / Fsharp Orleans ScaffoldF# + Orleans Basic Sample + Scaffold
dferenc-pannoniacode / BlazorSignalrOrleansA simple example of Blazor and Microsoft Orleans integration via SignalR for real-time communication in .NET 7.
seniorquico / OrleansDockerSampleAn example project and guide demonstrating an Orleans cluster in Docker containers.
VinayakVasisht / The Prodigal Son Inspiration On Friday, August 23, 1912, four-year-old Bobby Dunbar along with his family were staying at their family cabin in Louisiana on Swayze Lake, a heavily wooded area that was more like a swamp. The 11 party members included Bobby's parents Lessie and Percy Dunbar, Bobby's brother Alonzo, as well as several other family and friends. On that day, Percy Dunbar, Bobby's father, had to leave for work much to young Bobby's dismay, who, in a tantrum about his father leaving, broke the strap of his straw hat. Lessie, Bobby's mother, was preparing for a fish fry. Bobby then expressed that he wanted to go with Paul Mizzi, a family friend, to the lake to shoot garfish. Paul often took Bobby horseback riding and had an affectionate nickname for him, "Heavy". His mother allowed it and the rest of the boys in the party decided to join. Later, the group of boys were called back for lunch and they started making their way back, though from here the details get fuzzy. Paul recalled putting Bobby's brother Alonzo on his shoulders, joking with Bobby, "get out of the way, Heavy, or I'll run you over." Bobby's response, what some newspapers report as his last words, was characteristic to his personality, retorting, "you can't do it. You ain't no bigger than me." When they returned back to camp, Lessie realized her son, Bobby, was no longer with the group and was missing. She and Paul began to call out for Bobby in a panic and at one point Lessie fainted into the dirt. Three men from the party began to search north on the wagon trail behind the camp, in case Bobby had gone after his father. On their search, they ran into Percy on his way back from working, who raced to camp when he heard of Bobby's disappearance. By that night, with no trace of Bobby, searchers began to look for Bobby's body. They used dynamite to blast throughout the lake while a thick cable with massive hooks stretched across the length to drag the depths. After the night was over, divers also went into the lake to search any coves the hooks were unable to reach or places where a body could get trapped in the weeds. The only corpse they turned up from these efforts was that of a deer. Because Bobby's body had not been recovered in the lake, searchers believed he could have been killed by an animal, with the most likely predator being an alligator. Searchers even cut alligators open hoping they might find his remains inside, to no avail. By Saturday, August 24th, about 500 men had come to search for Bobby. Searchers even did a test using a straw hat with a broken strap like the one Bobby had on to test how long it could float, finding that it could float uninhibited for hours, leading searchers to believe there should have at least been some evidence of Bobby's hat. The stress of Bobby's disappearance caused his mother Lessie to become grievously ill and most of the family had to return to their home in Opelousas, Louisiana. Paul Mizzi, who had been the last adult to see Bobby alive, along with two other men who had been guests at that fateful fish fry that day would stay and continue to search for weeks more. Searchers found a solitary set of bare footprints leading toward a railroad trestle bridge heading out of the swamp, with still no body or even a trace of evidence to prove he had been killed by an animal. Those who continued the desperate search began to question if Bobby could have been kidnapped. It was speculated that someone in a small boat could have taken him through the north end of the lake into the bayou or someone on foot could have taken him on the trail or down the train tracks. Searchers had run into stragglers walking along the tracks and began to question if one of them could have taken Bobby. By August 26th, the authorities had also contacted the police in New Orleans about 130 miles away to search for Bobby there, giving those invested in the theory of his kidnapping further hope and official validation. Percy Dunbar would also go to New Orleans himself to distribute 700 copies of Bobby's picture and talked with many reporters. A detective agency made postcards with a picture and description of Bobby and mailed them to town and county officials from East Texas to Florida. The description of Bobby that was widely distributed read, "age four years and four months; full size for age; stout but not fat; large, round blue eyes; light hair and very fair skin, with rosy cheeks. Left foot had been burned when a baby and shows a scar on the big toe, which is somewhat smaller than big toe on the right foot. Wore blue rompers and a straw hat; without shoes." The Dunbar's whole home town of Opelousas held out hope that Bobby was still alive and together contributed to a $1,000 reward, which was "to be paid to any person or persons who will deliver to his parent's alive little Robert Clarence Dunbar. No questions asked." In 1912, this was a relatively enormous amount, roughly equivalent to about $22,000 today. However, after over eight months with no sign of Bobby, the unused reward money was returned to the townspeople who had donated it, but only a week after a major lead in the case broke. In April, 1913, a wire from the Ladies of Hub came to alert the Dunbars that an old tinker/peddler named William Cantwell Walters was spotted in the small town of Hub in southern Mississippi with a boy resembling Bobby, though his foot had been too covered in grime for anyone to get a good look. Walters had given authorities various and inconsistent answers about who the child belonged to, saying it was his own, his sister's, et cetera. Eventually the Ladies had witnessed Walters whipping the child, finally giving a citizens' committee enough to temporarily detain Walters and examine the boy, which they then firmly believed was Bobby, but asked the Dunbars to send further photo evidence. The Dunbars remained skeptical until they in turn received photos of the boy, and at this point the Dunbars traveled to Mississippi to see him in person, still not sure if it was their Bobby. The boy they had found had a scar on his left foot, as well as a mole on his neck where Bobby had one. However, he refused to answer to the name Bobby and when Lessie tried to hold him, he refused to interact with her. Lessie asked to see the boy again the next day and in their time together was able to give him a bath. At this point, she felt without any doubt that they had found Bobby. In a wave of emotion, she's recalled as shouting, "thank God, it is my boy" before fainting. Meanwhile, William C. Walters, the man whom the boy was taken from, was insistent that the boy was not Bobby Dunbar, but in fact Bruce Anderson. Walters claimed the boy was the illegitimate son of his brother and a woman named Julia Anderson, who had cared for his elderly parents back home in Barnesville, North Carolina. Julia Anderson was a single mom who did in fact work as a field hand and a caretaker for William Walters's parents. Walters claimed that Julia had given him the boy willingly, which Julia did confirm, though she disputed some of the details of his story, telling the paper, "Walters left Barnesville, North Carolina, with my son, Charles Bruce, in February of 1912, saying that he only wanted to take the child with him for a few days on a visit to the home of his sister. I have not seen the child from that day to this. I did not give him the child, I merely consented for him to take my son for a few days." Some were skeptical at his motives to claim he was given consent to take the child, as kidnapping was a capital offense in Louisiana and he could be just trying to avoid the kidnapping charge. He wrote to the Dunbars explaining so much and begged them to send for her, saying, "I know by now you have decided. You are wrong, it is very likely I will lose my life on account of that and if I do the Great God will hold you accountable." A newspaper in New Orleans arranged to bring Julia Anderson to Mississippi so she could identify the boy as well and she arrived in Opelousas on May 1st, 1913. However, stepping into the Dunbar's hometown, Julia Anderson was essentially already on enemy territory, as the town had already decided that the boy was Bobby Dunbar, who had miraculously come back to them. His return was made into a huge spectacle and he rode through town and into the square on a fire engine covered in flowers. When Julia Anderson met the boy, he did not react well to her, much like he had originally acted with Lessie Dunbar, though he may still have been reeling from the many sudden changes in his life, including the fact that in his beautiful new home he had just been given a pony and a bicycle. Additionally, Anderson had been missing her son for even longer than the Dunbars. It had been 15 months since she had allowed Walters to take Bruce and he had never returned with him. Similar to Lessie Dunbar, at first Anderson also had trouble identifying the boy as her son, but soon after stated that "her mother's heart" knew that the boy was her son. However, unlike with Lessie Dunbar, Anderson's initial uncertainty was not easily forgiven by the press. The press largely demonized her for having three children by two different men and it was implied she was a prostitute. Others called her illiterate and naive. They also called attention to the fact that she had lost all of her children within just a year. She had to give her daughter up for adoption, she had a baby who died a sudden death that she was wrongfully blamed for, then Bruce was taken from her. An article written in the New Orleans Item wrote of Anderson, "she had not seen her son since February of 1912, she had forgotten him. Animals don't forget, but this big, coarse country woman, several times a mother, she forgot." A court-appointed arbiter ruled that the boy was the Dunbar's missing son rather than Anderson's, as Anderson had no lawyer, no money, and no allies in Opelousas. She left town and the boy was uncontestedly allowed to remain Bobby Dunbar. William Walters went through a two-week trial that was described by some as "sensational", at which he was convicted of kidnapping and sentenced to life in prison. After just two years in jail, William Walters' verdict was overturned on an appeal and he was granted a new trial on a technicality. As for the boy, he grew up and lived as Bobby Dunbar. At 18, he fell in love with a girl named Marjorie from a nearby town. They married in 1935 and had four children. He passed away in 1966, always believing he was Bobby Dunbar, but this story doesn't end there. Skipping forward to 1999, Bobby Dunbar's granddaughter, Margaret Dunbar Cutright, began looking deeper into her family's history. Cutright had always been especially intrigued by the family legend of her grandfather's kidnapping and had asked her grandmother to tell her the story many times in her childhood. It was then a story that she told to her own children. A scrapbook with over 400 articles about the Dunbar case was given to Cutright by her father. She writes of the project, "the scrapbook was like a jigsaw puzzle without the picture on the box, and over the next few months, I lost myself in trying to piece it together." She was especially affected by an editorial cartoon from 1913 titled "Fifty Years From Now", in which a bearded old man sits in a chair with his grandson looking at newspapers from the Dunbar kidnapping trial and asks, "Grandpa, do you think we'll ever know for certain what our right name is." Cutright instantly noticed discrepancies in how newspapers were reporting the events. For example, there were at least two different reported versions of Lessie and Bobby's reunion. One paper stated that Lessie recognized Bobby immediately, while the other described Lessie as unsure, even including a quote from Lessie saying, "I do not know, I am not quite sure." She also found that Percy and Lessie had originally told the papers that the boy didn't look like their son, and that his eyes were too small. Some newspapers also reported Bobby didn't recognize his father, mother, or brother Alonzo. She also was disturbed to read the many biased accounts of Julia Anderson from the time and to read that from Anderson's perspective, she had felt that the Dunbars had kidnapped her son. Linda Tarver, the granddaughter of Julia Anderson, says of the family perception, "all of us cousins grew up, we knew that we had an uncle that had been taken by the Dunbar family in Opelousas, Louisiana. We always said kidnapped. We said they kidnapped him." Cutright continued her search obsessively, researching at small town libraries, archives, and courthouses all over the south. Eventually, the idea of testing her grandfather's DNA came up. Cutright's father, Bobby Dunbar Jr., agreed to give a DNA sample to compare with a sample given by one of her great-uncles, a son of Bobby's brother Alonzo. This was a controversial choice and many in the family urged Dunbar to leave the past alone. Gerald Dunbar, one of Cutright's uncles, said of the matter, "no matter how a DNA test turns out, there's going to be a sense of loss. What is to be truly gained." Exactly, when the test results came back, shockingly, the samples did not match, leaving Bobby's son Robert Dunbar Jr. himself surprised. He said of the outcome, "my intent was to prove that we were Dunbars. The results didn't turn out that way, and I have had to do some readjusting of my thinking. But I would do it again." Still, although this test proves that the boy was not Bobby Dunbar, there does not seem to have been a test administered to prove that the boy was in fact Bruce Anderson. Hollis Rawls, Anderson's son, had expressed a willingness to submit DNA before he passed away, but even without confirmation of that DNA evidence, many were apt to believe that Bobby Dunbar had actually been Bruce Anderson. In terms of incorrectly identifying himself as a Dunbar, Bobby Dunbar Jr. recalled a conversation he had with his father when he was a teenager in which he asked his father how he knew he was Bobby Dunbar and remembered his father telling him, "I know who I am, and I know who you are, and nothing else makes a difference." This settles the mystery of the boy that was found and yet the chilling mystery surrounding the boy lost continues to persist. Many wonder what actually happened to Bobby Dunbar that day. Some continue to believe that he was eaten by an animal, such as an alligator or a bear, though no evidence such as clothing was ever found to suggest that. Some wonder if he was actually kidnapped after all. In an interview in 1932, Bobby Dunbar, who was probably Bruce Anderson, recalled a memory of his time with William Walters in which he revealed that he remembered that there was another boy with him who fell off the wagon and died and was buried. Some wondered if the memory had been a memory of suggestion, as there had been theories posed by the prosecution at Walters's trial that he could have kidnapped both Anderson and Dunbar. Psychologically, some posit these theories could have allowed the boy to rationalize Bruce Anderson's death and allowed a narrative as Bobby Dunbar to begin.
