feat(routing): Contract based routing integration

[Sarthak1799]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

• Built an interface for Contract based routing
• Integrated Contract based routing with hyperswitch
• Built new APIs for contract routing config setup
• Refactored some existing dynamic routing code

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

How did you test it?

1. Enable Contract routing config

curl --location --request POST 'http://localhost:8080/account/sarthak2/business_profile/pro_YozTgS8HebvBlk0UaeWW/dynamic_routing/contracts/toggle?enable=dynamic_connector_selection' \
--header 'api-key: dev_1aD8YuFd6Ovanf3oOtAYobqI6qw4ZBRSfw6BgYbifWHpaopkisBtm8obNXkFbVJn' \
--header 'Content-Type: application/json' \
--data-raw '{
    "config": {
        "constants": [0.7,0.35],
        "time_scale": "day"
    },
    "label_info": [{
        "label": "stripe",
        "target_count": 10000,
        "incremental_count": 0,
        "target_time": 1780486655,
        "mca_id": "mca_5Mk0Qcum2tnbmKoyqeuL"
    }]
}'

Response -

{
    "id": "routing_FlQ49V71J8ZCXEwPzFy9",
    "profile_id": "pro_YozTgS8HebvBlk0UaeWW",
    "name": "Contract based dynamic routing algorithm",
    "kind": "dynamic",
    "description": "",
    "created_at": 1734009361,
    "modified_at": 1734009361,
    "algorithm_for": "payment"
}

2. Set Volume split for dynamic routing

curl --location --request POST 'http://localhost:8080/account/sarthak2/business_profile/pro_YozTgS8HebvBlk0UaeWW/dynamic_routing/set_volume_split?split=80' \
--header 'api-key: dev_1aD8YuFd6Ovanf3oOtAYobqI6qw4ZBRSfw6BgYbifWHpaopkisBtm8obNXkFbVJn'

3. Create a Payment
   Metrics Population post payment -

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/external_services/build.rs	35% smaller
crates/api_models/src/events/routing.rs	35% smaller
crates/router/src/routes/app.rs	26% smaller
crates/storage_impl/src/redis/pub_sub.rs	23% smaller
crates/router/src/core/payments/routing.rs	15% smaller
crates/api_models/src/routing.rs	12% smaller
crates/external_services/src/grpc_client/dynamic_routing.rs	10% smaller
crates/router/src/core/payments/operations/payment_response.rs	5% smaller
crates/storage_impl/src/redis/cache.rs	3% smaller
crates/router/src/core/routing.rs	2% smaller
api-reference/openapi_spec.json	1% smaller
.github/CODEOWNERS	Unsupported file format
crates/external_services/src/grpc_client/dynamic_routing/contract_routing_client.rs	0% smaller
crates/openapi/src/openapi.rs	0% smaller
crates/openapi/src/routes/routing.rs	0% smaller
crates/router/src/core/errors.rs	0% smaller
crates/router/src/core/metrics.rs	0% smaller
crates/router/src/core/payments.rs	0% smaller
crates/router/src/core/routing/helpers.rs	0% smaller
crates/router/src/routes/metrics/bg_metrics_collector.rs	0% smaller
crates/router/src/routes/routing.rs	0% smaller
proto/contract_routing.proto	Unsupported file format

[Chethan-rao]

is it ok to loose old entries in this vector as you are completely overriding it?

[Sarthak1799]

This case would only arise when we don't have any existing entries in the vec

[Chethan-rao]

this method is supposed to be a get call right as per the name, but we are returning mutable reference. should we have separate method for get and set instead of returning mutable reference.
Can be taken in separate PR

[Chethan-rao]

this update method currently updates all the fields. its better to have separate update methods for each fields to improve visibility
Again can be taken up in separate PR

[Sarthak1799]

This is updating the algorithm right?