2022-12-25 18:52:03 +00:00
<!doctype html> < meta charset = utf-8 > < meta name = viewport content = "width=device-width,initial-scale=1" > < link rel = stylesheet href = https://cdnjs.cloudflare.com/ajax/libs/github-markdown-css/5.1.0/github-markdown-dark.css > < style > . markdown-body { box-sizing : border-box ; min-width : 200 px ; max-width : 980 px ; margin : 0 auto ; padding : 45 px } @ media ( max-width : 767px ) { . markdown-body { padding : 15 px } } < / style > < body class = markdown-body > < a href = index > Index< / a > < h1 > < a id = user-content-reload-config class = anchor aria-hidden = true href = #reload-config > < span aria-hidden = true class = "octicon octicon-link" > < / span > < / a > Reload config< / h1 > < p > This serves as design draft of reload config system< div class = "highlight highlight-source-wsd" > < pre > < span class = pl-k > @startuml< / span > Reload config
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > skinparam< / span > < span class = pl-k > defaultFontName< / span > < span class = pl-s > Iosevka Term SS08< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > participant< / span > < span class = pl-c1 > admin< / span >
< span class = pl-k > participant< / span > < span class = pl-c1 > other_service< / span >
< span class = pl-k > participant< / span > < span class = pl-c1 > config_service< / span >
< span class = pl-k > participant< / span > < span class = pl-c1 > storage< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > ==< / span > < span class = pl-s > Admin handle< / span > < span class = pl-k > ==< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > admin< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > config_service< / span > : set/update/delete config
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > config_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > storage< / span > : set/update/delete config
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > ==< / span > < span class = pl-s > Other service handle< / span > < span class = pl-k > ==< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > other_service< / span > : init service
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > activate< / span > < span class = pl-c1 > other_service< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > storage< / span > : make connection
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > loop< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > storage< / span > : listen on config change
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > other_service< / span > : save config to memory
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > end< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > deactivate< / span > < span class = pl-c1 > other_service< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > other_service< / span > : do business
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > activate< / span > < span class = pl-c1 > other_service< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > other_service< / span > : get config
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-c1 > other_service< / span > < span class = pl-k > -> < / span > < span class = pl-c1 > other_service< / span > : do other business
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > deactivate< / span > < span class = pl-c1 > other_service< / span >
2022-10-26 15:08:03 +00:00
2022-12-25 18:52:03 +00:00
< span class = pl-k > @enduml< / span > < / pre > < / div > < p > Config storage can be any key value storage or database like etcd, Consul, mySQL, ...< p > If storage is key value storage, maybe there is API to listen on config change.
Otherwise we should create a loop to get all config from storage for some interval, for example each 5 minute.< p > Each < code > other_service< / code > need to get config from its memory, not hit < code > storage< / code > .
So there is some delay between upstream config (config in < code > storage< / code > ) and downstream config (config in < code > other_service< / code > ), but maybe we can forgive that delay (???).< p > Pros:< ul > < li > < p > Config can be dynamic, service does not need to restart to apply new config.< li > < p > Each service only keep 1 connection to < code > storage< / code > to listen to config change, not hit < code > storage< / code > for each request.< / ul > < p > Cons:< ul > < li > Each service has 1 more dependency, aka < code > storage< / code > .< li > Need to handle fallback config, incase < code > storage< / code > failure.< li > Delay between upstream/downstream config< / ul > < a href = mailto:hauvipapro+posts@gmail.com > Feel free to ask me via email< / a >
2022-11-26 05:03:16 +00:00
< a rel = me href = https://hachyderm.io/@haunguyen > Mastodon< / a >
