Overview » History » Version 18
J. Wienke, 06/10/2011 06:08 PM
1 | 1 | J. Wienke | h1. Overview |
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2 | 1 | J. Wienke | |
3 | 8 | J. Wienke | h2. Problem statement |
4 | 8 | J. Wienke | |
5 | 8 | J. Wienke | * easier integration of complex (partially) distributed systems required |
6 | 8 | J. Wienke | ** in-house (one middleware) |
7 | 8 | J. Wienke | ** adaption (combination with other middlewares) |
8 | 8 | J. Wienke | * targeting at technical architecture (only supporting functional concepts) |
9 | 8 | J. Wienke | * performance requirements |
10 | 8 | J. Wienke | * platform requirements |
11 | 9 | J. Wienke | * programming language requirements |
12 | 12 | J. Wienke | ** desired set of languages |
13 | 12 | J. Wienke | ** natural feeling in each language by using native mechanisms |
14 | 9 | J. Wienke | * basis for describing and analyzing systems required |
15 | 11 | J. Wienke | * open architecture required |
16 | 1 | J. Wienke | ** specifications for data format and transport protocols |
17 | 11 | J. Wienke | ** use of existing (and open) naming services |
18 | 8 | J. Wienke | |
19 | 7 | J. Wienke | h2. Sebastian's Aims |
20 | 1 | J. Wienke | |
21 | 10 | J. Wienke | * XCF support ends |
22 | 1 | J. Wienke | ** better solution required |
23 | 11 | J. Wienke | * limited client interface that converts to domain data as soon as possible to prevent dependency on middleware throughout the whole client code |
24 | 12 | J. Wienke | * variable dispatching mechanisms not forced by the framework |
25 | 1 | J. Wienke | |
26 | 15 | J. Wienke | h2. Lessons learned (from other frameworks, e.g. XCF, YARP, ROS, NaoQi) |
27 | 1 | J. Wienke | |
28 | 15 | J. Wienke | identified problems: |
29 | 15 | J. Wienke | |
30 | 15 | J. Wienke | * Footprint too large for embedded systems |
31 | 15 | J. Wienke | * Architectural erosion |
32 | 15 | J. Wienke | * Unmaintainable code base |
33 | 15 | J. Wienke | * important parameters and implicit assumptions should not be hidden in the code for analysis |
34 | 15 | J. Wienke | * missing introspection functionalities |
35 | 15 | J. Wienke | * bad error handling strategies, e.g. missing transparency for the client (i.e. swallowed exceptions) |
36 | 15 | J. Wienke | |
37 | 15 | J. Wienke | lessons learned: |
38 | 15 | J. Wienke | |
39 | 15 | J. Wienke | * layered architecture with improved functional decomposition in distinct libraries, layers: |
40 | 15 | J. Wienke | ** core (bus realization across different transports) |
41 | 15 | J. Wienke | ** tools |
42 | 15 | J. Wienke | ** XML compatibility layer |
43 | 15 | J. Wienke | ** XCF API adapters |
44 | 15 | J. Wienke | * clear dependency statements: |
45 | 15 | J. Wienke | ** core must survive with the least amount of external libraries |
46 | 15 | J. Wienke | ** different language implementation should not depend on a single base implementation (reduce development and deployment complexity, increase usability of the framework) |
47 | 15 | J. Wienke | * development process |
48 | 15 | J. Wienke | ** developer team ;) |
49 | 15 | J. Wienke | ** clear testing strategies |
50 | 15 | J. Wienke | ** continuous integration |
51 | 15 | J. Wienke | * allow more flexibility through defined interfaces and protocols |
52 | 15 | J. Wienke | ** allow different transports, e.g. in-process |
53 | 15 | J. Wienke | ** encoding flexibility for user data to meet domain and performance requirements |
54 | 15 | J. Wienke | * provide additional system structures like services to aggregate coherent functionality |
55 | 7 | J. Wienke | |
56 | 17 | J. Wienke | h2. Functional properties (so far): |
57 | 2 | J. Wienke | |
58 | 1 | J. Wienke | * Event-driven middleware with broadcast semantics |
59 | 17 | J. Wienke | ** Additional communication patterns implemented on top of this base functionality |
60 | 1 | J. Wienke | * logically unified bus across multiple transports |
61 | 1 | J. Wienke | ** currently a spread-based and an in-process transport are available |
62 | 4 | J. Wienke | ** extensible to other transports -> compatibility to existing frameworks |
63 | 1 | J. Wienke | * Bus is structured by hierarchical channels |
64 | 1 | J. Wienke | ** / receives all messages of sub-scopes like /a/test |
65 | 16 | J. Wienke | * Support for filtering events: |
66 | 16 | J. Wienke | ** content-based |
67 | 16 | J. Wienke | ** on meta-data |
68 | 16 | J. Wienke | |
69 | 16 | J. Wienke | Adopted concepts (from XCF): |
70 | 16 | J. Wienke | * event-driven |
71 | 16 | J. Wienke | * broadcast semantics |
72 | 16 | J. Wienke | * content-based filtering |
73 | 16 | J. Wienke | * introspection |
74 | 2 | J. Wienke | |
75 | 17 | J. Wienke | h2. Non-functional properties (so far): |
76 | 2 | J. Wienke | |
77 | 17 | J. Wienke | * lightweight (will remain [for the core]): |
78 | 2 | J. Wienke | ** small dependency footprint for the core layer |
79 | 2 | J. Wienke | ** Targeting at embedded systems (e.g. Nao) |
80 | 2 | J. Wienke | * Languages: cpp, java, python, common lisp |
81 | 2 | J. Wienke | ** real implementations, no bindings to provide natural interfaces in each language |
82 | 2 | J. Wienke | * No single wire type like XML: |
83 | 2 | J. Wienke | ** instead arbitrary client data is serialized to different wire types using (user-installed) converters |
84 | 6 | J. Wienke | *** default set of converters exists (e.g. source:/trunk/cpp/core/src/rsb/converter/StringConverter.cpp) |
85 | 3 | J. Wienke | ** provide flexible and fast serialization mechanisms |
86 | 3 | J. Wienke | ** XML support layer as additional library |
87 | 18 | J. Wienke | * performance requirements on network-based (UDP) and in-process transport |
88 | 18 | J. Wienke | ** no hard real-time |
89 | 18 | J. Wienke | ** avoid serialization when possible |
90 | 3 | J. Wienke | |
91 | 3 | J. Wienke | h2. Planned functionality: |
92 | 3 | J. Wienke | |
93 | 3 | J. Wienke | * naming and discovery |
94 | 3 | J. Wienke | * introspection tools |
95 | 3 | J. Wienke | * model-based setup |