Snapshot of Config/ Config Versions

[pratikmishra356]

Introducing new feature - Config Versions. We will now support version history for configs which included contexts, overrides and default configs.

[pratikmishra356]

Database Design

CREATE TABLE public.config_versions (
id bigint PRIMARY KEY,
config json NOT NULL,  -- stores config
config_hash TEXT NOT NULL,  -- stores hash of config 
tags varchar(100)[] check (array_position(tags, null) is null),  - user can tag any particular changes in the config
created_at timestamp without time zone DEFAULT CURRENT_TIMESTAMP NOT NULL
 );

Api changes

Apis need to be added/updated :

Endpoint: /config/versions → add
Method: GET
Description: metadata for version history.

Endpoint: /config?version=”” → update
Method: GET
Description: will take version in query params, if version not provided, it will give the latest config

*1 - This will accept another field tags of type Option<Vec<String>> by which user can tag the particular changes
Endpoint: /context
Method: PUT
Description: *1

Endpoint: /context/move/{ctx_id} → update
Method: PUT
Description: *1

Endpoint: /context/{ctx_id} → update
Method: DELETE
Description: *1

Endpoint: /priority/recompute → update
Method: DELETE
Description: *1

Endpoint: /default-config/{key} → update
Method: PUT
Description: *1

Endpoint: /default-config/{key} → update
Method: DELETE
Description: *1

Client Changes

While initiating cac_client we would require two extra parameters -
top_n_config - integer // defaults to 5, max restricted to 50
filter_tags : array of string // filtered based on atleast any one in the given list should be present in table tags column
client functions eval, get_resolved_config, get_default_config will accept one more optional parameter version, if version not provided , it will assume the latest config from the stored configs

[Datron]

client functions eval, get_resolved_config, get_default_config will accept one more optional parameter version, if version not provided , it will assume the latest config from the stored configs

@pratikmishra356 if version provided to these eval, get_resolved_config, get_default_config isn't present in the client, will we go to server to fetch the data?

[pratikmishra356]

yes we should fetch from server

[pratikmishra356]

Approach for Adding x-config-version-id in response headers:

Following Apis will have this header in response :
Context - create/update/delete/move
Default-Configs - create/update/delete
Config - All get requests

Implementation Approach :

1. Adding in middleware by extracting method and route ( not sure how this will work)
2. Overriding responder trait for Json

[Datron]

@pratikmishra356 you mentioned that you are adding functions to each handler. Can you elaborate on that approach?

[pratikmishra356]

@Datron
Problem Statement is we need to add headers for some group of apis

Approach is , that we will define a struct CustomResp with responder trait implementation ,
This struct will accept body and headers , and it will create an http response with the given body and headers.
In handler we can construct this struct and return just like Json struct

[Datron]

Sure, sounds good.