2023-06-12 02:36:24 +00:00
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<img src="FlexiLib.svg" width=100px/>
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2023-06-03 20:57:07 +00:00
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FlexiLib
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========
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This is a web server written with the following goals:
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* Low memory consumption
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* Low latency
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* Flexible "reverse proxy" capabilities
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* Ability to simulate FAAS capabilities of various online providers (AWS, CloudFlare, etc)
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This last point is indirectly supported through the ability of the server to
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load, at run time, dynamic libraries to support requests. It will also reload
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these libraries after any in flight requests have completed, to support the
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experience of developing new libaries.
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Libraries can be written in any programming language that supports a standard
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Linux C-Based calling convention, which is to say, nearly every programming
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language.
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This project provides slightly better development and performance characteristics
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if the library used is written in [zig](https://ziglang.org). An example zig-based
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library can be found in src/main-lib.zig.
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Architecture
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------------
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2023-06-03 20:59:42 +00:00
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TODO:
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2023-06-03 20:57:07 +00:00
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We assume Linux.
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2023-06-03 21:26:37 +00:00
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Built with zig 0.11.0-dev.3312+ab37ab33c (provide permalink). Explain lock to 0.11 when released.
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2023-06-03 20:57:07 +00:00
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To achieve the lowest latency possible and eliminate the proliferation, The architecture of this server is setup
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Security
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--------
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There is little attempt to secure libraries from interfering with the current
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thread or even the main process. As such, the libraries should be fully trusted.
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However, libraries themselves may be hardened to run other non-trusted code.
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For example: A "I run WASM code" library may be written to create a WASM VM and
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run user-supplied WASM code. In that case, the "I run WASM code" library is
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trusted, although the code it runs may not be.
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Configuration
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-------------
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Very little has been done so far in terms of configuration. By default, the
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number of threads created to serve requests is equal to the number of CPUs
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reported by the system (although thread count is limited to 4 threads when
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compiled in debug mode). This can be controlled with the environment variable
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`SERVER_THREAD_COUNT`.
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Future plans include an environment variable for IP address and port to listen
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on, as well as the amount of pre-allocated memory for response data (currently
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hardcoded to 1k/thread). Pre-allocated memory reduces the number of system
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calls required for memory allocation, and pre-allocation/allocation statistics
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per request are reported in the logs.
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Logs
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----
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Request logs are sent to standard out, and are likely to change. Here is a sample:
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```
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127.0.0.1:59940 - - "GET / HTTP/1.1" 200 ttfb 2000.420ms 11 ttlb 2000.568ms (pre-alloc: 1569, alloc: 4350)
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```
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The first part mirrors common logs from Apache/nginx.
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ttfb: Time to first byte. This represents the number of ms of processing within the library
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ttlb: Time to last byte. This includes processing as well a transmission of data
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pre-alloc: The amount of memory actually pre-allocated (1k is just a minimum and the system may allocate more)
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alloc: The amount of memory actually allocated during the request
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