feat: prepare API for Render deployment (PostgreSQL, health check, CORS, Swagger, pagination)

[devin-ai-integration]

Summary

Makes the API deployable to Render: adds PostgreSQL support, a render.yaml blueprint, an unauthenticated /health check, configurable CORS, Swagger, and pagination on GET /api/v1/readings.

Database provider selected at runtime

AppDbContext.OnConfiguring now picks the provider from DATABASE_URL:

var connectionString = Environment.GetEnvironmentVariable("DATABASE_URL");
if (!string.IsNullOrEmpty(connectionString))
    optionsBuilder.UseNpgsql(NormalizePostgresConnectionString(connectionString));
else
    optionsBuilder.UseSqlite($"DataSource={dbPath};Cache=Shared"); // local-dev fallback

Render exposes connection strings as URIs (postgres://user:pass@host:port/db), which Npgsql does not accept directly, so NormalizePostgresConnectionString converts a postgres(ql):// URI into the Npgsql key/value format (and passes through already-formatted strings). A new EF migration InitialPostgres was generated against the Npgsql provider.

Because EF migrations are provider-specific, startup now branches:

if (context.Database.IsNpgsql())
    context.Database.Migrate();      // production / PostgreSQL
else
    context.Database.EnsureCreated(); // SQLite local-dev fallback

(The repo previously had no committed migrations even though Program.cs called Migrate(), so the SQLite path effectively created no schema — EnsureCreated() fixes local dev too.)

/health endpoint

New HealthController returns 200 { "status": "healthy" }. ApiKeyAuthMiddleware short-circuits before key validation for /health so Render's health probe works without the API key:

if (context.Request.Path.StartsWithSegments("/health")) { await _next(context); return; }

CORS + Swagger (Startup.cs)

• Startup now takes IConfiguration. CORS policy FrontendPolicy reads ALLOWED_ORIGINS (comma-separated); when empty it falls back to AllowAnyOrigin (dev-friendly). app.UseCors(...) runs before the API-key middleware and routing.
• Swagger registered with an X-API-KEY ApiKey security scheme; the UI is exposed only outside Production.

Pagination on GET /api/v1/readings

Adds page (default 1) and pageSize (default 50, clamped to 200) and returns a typed envelope PagedResult<Reading> serialized as { data, page, pageSize, total } (ordered by CreatedAt desc). A concrete DTO is used instead of an anonymous type so the response is assertable from the test assembly; ReadingControllerTests were updated for the new contract and two pagination tests added.

Infra / config

• render.yaml (Docker web service + free PostgreSQL, healthCheckPath: /health, DATABASE_URL from the DB, ApiKey/ALLOWED_ORIGINS as sync: false).
• appsettings.Production.json with reduced log verbosity.
• .dockerignore now excludes appsettings.Development.json, local secrets, and *.sqlite*.
• README documents the Render deployment and required env vars.

Verification

dotnet build -c Release and dotnet test pass (91/91). Ran locally against the SQLite fallback: /health → 200 without key, readings → 401 without key, paginated envelope returned with key, CORS preflight returns headers, and /swagger/v1/swagger.json serves in Development.

Link to Devin session: https://app.devin.ai/sessions/829418a074784cbaa96bc62faf058bea
Requested by: @joaoferreira-dev

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[Copilot]

Pull request overview

Prepares the AirAware ASP.NET Core API for deployment on Render by adding PostgreSQL support (via DATABASE_URL), health checks, configurable CORS, Swagger, and paginated responses for readings.

Changes:

• Add Render blueprint (render.yaml) and production configuration (appsettings.Production.json), plus Docker ignore hardening.
• Add PostgreSQL runtime selection + initial Npgsql EF Core migrations; adjust startup to migrate on PostgreSQL and EnsureCreated() on SQLite.
• Add /health, Swagger (non-Production), CORS policy, and paginate GET /api/v1/readings with a typed PagedResult<T> (tests updated).

Reviewed changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
render.yaml	Render blueprint to provision the API service and PostgreSQL database.
README.md	Documents Render deployment, env vars, and SQLite vs PostgreSQL behavior.
AirAware/ViewModels/PagedResult.cs	Introduces a typed pagination envelope for API responses/tests.
AirAware/Startup.cs	Adds CORS + Swagger configuration and updates middleware pipeline.
AirAware/Program.cs	Applies migrations on PostgreSQL; uses EnsureCreated() for SQLite fallback.
AirAware/Migrations/AppDbContextModelSnapshot.cs	EF Core snapshot for the new PostgreSQL migration set.
AirAware/Migrations/20260614040505_InitialPostgres.Designer.cs	Generated migration designer for PostgreSQL schema.
AirAware/Migrations/20260614040505_InitialPostgres.cs	Creates initial PostgreSQL tables + indexes.
AirAware/Middleware/ApiKeyAuthMiddleware.cs	Exempts /health from API-key auth.
AirAware/Data/AppDbContext.cs	Selects provider from DATABASE_URL and normalizes Render-style Postgres URIs.
AirAware/Controllers/ReadingController.cs	Adds pagination parameters and returns PagedResult<Reading>.
AirAware/Controllers/HealthController.cs	Adds unauthenticated health check endpoint.
AirAware/appsettings.Production.json	Production log-level tuning and allowed hosts.
AirAware/AirAware.csproj	Adds Npgsql EF provider and Swashbuckle dependencies.
AirAware.Tests/Controllers/ReadingControllerTests.cs	Updates tests for the paginated response contract + adds pagination tests.
.dockerignore	Excludes dev configs/secrets and SQLite files from Docker build context.

Files not reviewed (1)

• AirAware/Migrations/20260614040505_InitialPostgres.Designer.cs: Generated file

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.