10.5 Schedule it, with retries

ManifestNames.cs:

namespace Shopfront;
 
// The external id of each manifest Shopfront schedules: its identity on every start and every host.
public static class ManifestNames
{
    public const string StockReport = "stock-report";
    public const string LowStockCheck = "low-stock-check";
    public const string Restock = "restock";
}

Program.cs:

using Shopfront;
using Shopfront.Auth;
using Shopfront.Data;
using Shopfront.Extensions;
using Shopfront.Staff;
using Shopfront.Suppliers;
using Shopfront.Trains.LowStockCheck;
using Shopfront.Trains.Restock;
using Shopfront.Trains.StockReport;
using Trax.Api.Auth.Jwt;
using Trax.Api.Dashboard.Extensions;
using Trax.Api.GraphQL.Extensions;
using Trax.Effect.Data.Extensions;
using Trax.Effect.Data.Postgres.Extensions;
using Trax.Effect.Data.Services.DomainContext;
using Trax.Effect.Enums;
using Trax.Effect.Extensions;
using Trax.Effect.JunctionProvider.Logging.Extensions;
using Trax.Effect.Models.Manifest;
using Trax.Effect.Provider.Parameter.Extensions;
using Trax.Mediator.Extensions;
using Trax.Scheduler.Extensions;
using Trax.Scheduler.Services.Scheduling;
 
var builder = WebApplication.CreateBuilder(args);
 
var connectionString =
    builder.Configuration.GetConnectionString("Shopfront")
    ?? throw new InvalidOperationException("ConnectionStrings:Shopfront is not set.");
var development = builder.Environment.IsDevelopment();
 
builder.Services.AddShopfront(connectionString);
 
if (development)
    builder.Services.AddTraxJwtAuth(jwt =>
        jwt.UseSymmetricKey(DevJwt.Issuer, DevJwt.Audience, DevJwt.Key)
    );
else
    builder.Services.AddTraxJwtAuth(
        builder.Configuration["Auth:Authority"]
            ?? throw new InvalidOperationException("Auth:Authority is not set."),
        builder.Configuration["Auth:Audience"]
            ?? throw new InvalidOperationException("Auth:Audience is not set.")
    );
builder.Services.AddAuthorization();
 
builder.Services.AddTrax(trax =>
    trax.AddEffects(effects =>
            effects
                .UsePostgres(connectionString)
                .SaveTrainParameters()
                .AddJunctionLogger(serializeJunctionData: true)
                .AddDecisionRecording()
                .AddJunctionEvents()
                .AddLifecycleHook<StaffFailureHook>()
        )
        .AddMediator(typeof(Program).Assembly)
        .AddScheduler(scheduler =>
        {
            // In Development, retries come seconds apart rather than minutes, to be watched.
            if (development)
                scheduler
                    .DefaultRetryDelay(TimeSpan.FromSeconds(5))
                    .MaxRetryDelay(TimeSpan.FromSeconds(30));
 
            return scheduler
                .Schedule<IStockReportTrain>(
                    ManifestNames.StockReport,
                    new StockReportInput(),
                    Cron.Daily(hour: 2),
                    options =>
                        options
                            // The shop's holidays: no count, and none the morning after.
                            .Exclude(
                                Exclude.Dates(new DateOnly(2026, 12, 25), new DateOnly(2027, 1, 1))
                            )
                            .OnMisfire(MisfirePolicy.DoNothing)
                            .Variance(TimeSpan.FromMinutes(10))
                )
                .ThenInclude<ILowStockCheckTrain>(
                    ManifestNames.LowStockCheck,
                    new LowStockCheckInput { Threshold = 3 }
                )
                .Schedule<IRestockTrain>(
                    ManifestNames.Restock,
                    new RestockInput { Threshold = 3 },
                    development ? Every.Minutes(1) : Every.Hours(1),
                    options => options.MaxRetries(2)
                );
        })
);
builder.Services.AddTraxGraphQL(graphql =>
    graphql
        .AddDbContext<ShopfrontDbContext>()
        .ExposeOperationQueries()
        .ExposeOperationMutations()
        .GateOperations(roles: Roles.Staff)
);
 
var app = builder.Build();
 
await app.Services.EnsureSchemaCreatedAsync<ShopfrontDbContext>();
 
app.UseAuthentication();
app.UseAuthorization();
app.UseTraxGraphQL();
app.UseTraxApiDashboard(dashboard => dashboard.AllowAnonymousShell());
 
if (development)
{
    app.MapGet(
            "/dev/token/{user}",
            (string user, bool staff = false) =>
                DevJwt.Mint(user, staff ? Roles.Staff : Roles.Customer)
        )
        .AllowAnonymous();
 
    // Takes the fake supplier down, or brings it back.
    app.MapPost(
            "/dev/supplier/{state}",
            (string state, FakeSupplier supplier) =>
            {
                supplier.IsDown = state == "down";
                return Results.NoContent();
            }
        )
        .AllowAnonymous();
}
 
await app.RunAsync();

What is new:

MaxRetries(2) retries a failed restock twice, so it runs at most three times. The third failure makes it a dead letter.
The backoff spaces the retries out. The first waits DefaultRetryDelay, five minutes by default, and each one after it waits twice as long as the last, up to MaxRetryDelay, an hour by default. Development uses five seconds and thirty, so the whole story takes less than a minute. These are the scheduler's settings, shared by every manifest.
AddLifecycleHook<StaffFailureHook>() registers the hook. It goes last in AddEffects, after the effects that need the data provider before them.
The restock runs every hour, and every minute in Development.
/dev/supplier/{state} flips the fake supplier, in Development only.

SDK Reference

Schedule | AddScheduler | How retries work | Resolve a dead letter | AddLifecycleHook

Next: 10.6 Watch it fail