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Server & App Patterns

When building a server (e.g., with Nitro.jl or Genie.jl), you need robust ways to initialize databases and check their health.

Using load_many for Multi-DB Servers

If your server talks to multiple static databases, load them all at once:

db_dirs = ["db", "db_analytics", "db_tenants"]
PormG.Configuration.load_many(db_dirs; env="prod")

# Then import models for each
PormG.@import_models "db/models.jl" app_models
PormG.@import_models "db_analytics/models.jl" ana_models

import .app_models as M
import .ana_models as AM

Health & Connectivity Checks

PormG provides high-level functions for monitoring connection status without leaking implementation details.

  • Check if Registered: PormG.Configuration.is_loaded("db")::Bool
  • Check if Reachable: PormG.Configuration.ping("db")::Bool (returns Bool)
  • Detailed Status: PormG.Configuration.status("db")::NamedTuple

Example health check for a Nitro.jl handler:

function health_check()
    db_status = PormG.Configuration.status("db")
    if db_status.reachable
        return (status="ok", db=db_status.app_env)
    else
        return (status="error", message="Database unreachable")
    end
end

status() returns a named tuple that distinguishes between three cases:

  • Not loaded: loaded = false, reachable = false
  • Loaded but unreachable: loaded = true, reachable = false
  • Loaded and reachable: loaded = true, reachable = true

Target ergonomics for a server app:

db_dirs = [dirname(settings["source_path"]) for settings in values(config.db)]
PormG.Configuration.load_many(db_dirs; env=config.env)

db_ok = all(PormG.Configuration.ping, db_dirs)
db_status = db_ok ? "connected" : "unavailable"

This is better DX than calling get_settings(dirname(...)) from the app because it makes the contract explicit:

  • load_many(...) is for bootstrapping.
  • is_loaded(...) is for registration checks.
  • ping(...) or status(...) is for health checks.