gesta 0.1.5

A Python library designed to handle administration for businesses.

Gesta

A Python library for hanling Gesta, a Customer Relationship Manager (CRM) — appointments, transactions, payments, and reporting in a clean, extensible API.

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Tutorial

For a detailed notebook tutorial, visit the following link:

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Features

• Appointment management — book, reschedule, cancel, and complete appointments with conflict detection
• Transaction tracking — register services rendered and products sold, with cost and profit tracking
• Payment management — register payments against one or multiple transactions, including partial payments and refunds
• Reporting — revenue summaries, profit margins, popular offerings, frequent clients, and more
• Extensible — adapt Gesta to any business type by extending the base Gesta class
• SQLite & PostgreSQL — works locally out of the box, ready for production with Postgres

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Installation

pip install gesta

Requires Python 3.12+.

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Quick start

from datetime import datetime, timedelta
from gesta.extensions import WellnessStudio

# Initialize — creates the database and tables automatically
studio = WellnessStudio(db_url="sqlite:///my_business.db")
studio.setup()

# Register a client and a provider
with studio.session() as s:
    client    = studio.add_client(s, name="Ana García",  phone="5551234567")
    therapist = studio.add_provider(s, name="Marta López", role="therapist")

# Book an appointment
with studio.session() as s:
    ana   = studio.list_clients(s)[0]
    marta = studio.list_providers(s)[0]

    appointment = studio.appointments(s).book(
        service_id   = "svc_masaje_sueco",
        client_ids   = [ana.id],
        provider_ids = [marta.id],
        scheduled_at = datetime.now() + timedelta(days=3),
    )

# Register the transaction when the service is delivered
with studio.session() as s:
    tx = studio.transactions(s).register_from_appointment(
        appointment_id = appointment.id,
        occurred_at    = datetime.now(),
    )

# Register payment
with studio.session() as s:
    from gesta.core.entities import PaymentMethod
    studio.payments(s).register(
        transaction_ids = [tx.id],
        amount          = tx.amount,
        method          = PaymentMethod.CASH,
        paid_at         = datetime.now(),
    )

# Monthly revenue report
with studio.session() as s:
    summary = studio.reports(s).monthly_summary(
        year  = datetime.now().year,
        month = datetime.now().month,
    )
    print(f"Revenue:   ${summary.total_revenue}")
    print(f"Collected: ${summary.total_collected}")
    print(f"Profit:    ${summary.total_profit}")
    print(f"Margin:    {summary.profit_margin}%")

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Core concepts

Entities

Entity	Description
Person	Any participant — client, therapist, instructor, etc.
Role	What role a person plays (is_provider, is_recipient)
Service	An offering that requires scheduling and a provider
Product	A physical offering with inventory
Appointment	A future reservation of a service
Transaction	A record that a service was delivered or a product was sold
Payment	A money movement linked to one or more transactions

Attributes of entities

Person

persons	Data type	Nullable
id	String	primary key
name	String(120)	F
email	String(120)	T
phone	String(30)	T
notes	Text	T
created_at	DateTime	F
updated_at	DateTime	F

Role

roles	Data type	Nullable
id	String	primary key
name	String(120)	F
description	Text	T
is_provider	Boolean	F
is_recipient	Boolean	F

Offering

offerings	Data type	Nullable
id	String	primary key
type	OfferingType	F
name	String(120)	F
description	Text	T
price	Numeric(10,2)	F
cost	Numeric(10,2)	T
is_active	Boolean	F
created_at	DateTime	F

donde OfferingType:

1. SERVICE
2. PRODUCT

Appointment

appointments	Data type	Nullable
id	String	primary key
service_id	String	foreign key
status	AppointmentStatus	F
scheduled_at	DateTime	F
registered_at	DateTime	F
notes	Text	T

donde AppointmentStatus:

1. SCHEDULED
2. COMPLETED
3. CANCELLED
4. NO_SHOW

Transaction

transactions	Data type	Nullable
id	String	primary key
appointment_id	String	foreign key
offering_id	String	foreign key
amount	Numeric(10,2)	F
cost_amount	Numeric(10,2)	T
status	TransactionStatus	F
occurred_at	DateTime	F
created_at	DateTime	F
notes	Text	T

donde TransactionStatus:

1. PENDING
2. PAID
3. PARTIAL
4. REFUNDED

Payment

payments	Data type	Nullable
id	String	primary key
amount	Numeric(10,2)	F
method	PaymentMethod	F
is_refund	Boolean	F
paid_at	DateTime	F
created_at	DateTime	F
notes	Text	T

donde PaymentMethod:

1. CASH
2. CARD
3. TRANSFER
4. OTHER

Transaction vs Appointment

These are two distinct events in time:

Monday 10am  →  Ana books a massage for Thursday     =  Appointment
Thursday 3pm →  Marta gives Ana the massage           =  Transaction
Thursday 3pm →  Ana pays $600 cash                   =  Payment (direct)

— or —

Thursday 3pm →  Ana doesn't pay that day             =  Payment pending
Friday 11am  →  Ana transfers $600                   =  Payment (indirect)

Price, cost, and profit

Every Service and Product has:

• price — what the client pays (per person / per unit)
• cost — what it costs the business to deliver
• margin — price - cost (property, computed automatically)

Every Transaction tracks:

• amount — total charged (price × number of clients)
• cost_amount — actual cost at the time of the transaction
• profit — amount - cost_amount (property)

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API Reference

Gesta — main class

The entry point of the library. Manages the database connection and exposes all managers.

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Gesta(db_url, echo=False)

Initializes the library, connects to the database, and creates all tables if they don't exist.

Parameter	Type	Description
db_url	str	SQLAlchemy connection URL
echo	bool	If True, prints generated SQL. Useful during development.

from gesta import Gesta

# SQLite — local file
studio = Gesta(db_url="sqlite:///business.db")

# SQLite — in memory (useful for tests)
studio = Gesta(db_url="sqlite:///:memory:")

# PostgreSQL
studio = Gesta(db_url="postgresql://user:password@localhost/gesta_db")

# With SQL logging enabled
studio = Gesta(db_url="sqlite:///business.db", echo=True)

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Gesta.session()

Context manager that provides a database session. Automatically commits on success and rolls back on exception.

# All operations inside one session are committed together.
# If any fails, all are rolled back.
with studio.session() as s:
    appt = studio.appointments(s).book(...)
    tx   = studio.transactions(s).register_from_appointment(appt.id, ...)
    studio.payments(s).register([tx.id], ...)

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Gesta.ping()

Returns True if the database is reachable, False otherwise.

if studio.ping():
    print("Database is up")
else:
    print("Cannot reach database")

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AppointmentManager — studio.appointments(session)

Manages the full lifecycle of appointments.

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.book(service_id, client_ids, scheduled_at, provider_ids=None, notes=None)

Creates a new appointment in SCHEDULED status.

Validates that scheduled_at is in the future, the service is active, all clients have a recipient role, all providers have a provider role, and no provider has a schedule conflict.

Parameter	Type	Description
service_id	str	ID of the service to book
client_ids	list[str]	IDs of clients attending
scheduled_at	datetime	Date and time of the appointment
provider_ids	list[str]	IDs of providers delivering the service
notes	str	Optional notes

from datetime import datetime, timedelta

with studio.session() as s:
    # Single client, single provider
    appt = studio.appointments(s).book(
        service_id   = "svc_masaje_sueco",
        client_ids   = ["client_id_1"],
        provider_ids = ["provider_id_1"],
        scheduled_at = datetime.now() + timedelta(days=3),
        notes        = "Client prefers light pressure",
    )

    # Group class — multiple clients
    appt = studio.appointments(s).book(
        service_id   = "svc_yoga_grupal",
        client_ids   = ["client_id_1", "client_id_2", "client_id_3"],
        provider_ids = ["instructor_id_1"],
        scheduled_at = datetime.now() + timedelta(days=1),
    )

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.get(appointment_id)

Returns an appointment by ID. Raises NotFoundError if it doesn't exist.

with studio.session() as s:
    appt = studio.appointments(s).get("appt_id_123")
    print(appt.status)
    print(appt.scheduled_at)

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.reschedule(appointment_id, new_datetime)

Changes the date and time of a SCHEDULED appointment. Validates the new datetime is in the future and checks for provider conflicts.

with studio.session() as s:
    studio.appointments(s).reschedule(
        appointment_id = "appt_id_123",
        new_datetime   = datetime.now() + timedelta(days=5),
    )

---

.cancel(appointment_id)

Marks an appointment as CANCELLED. Raises BusinessRuleError if the appointment already has a transaction associated.

with studio.session() as s:
    studio.appointments(s).cancel("appt_id_123")

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.complete(appointment_id)

Marks an appointment as COMPLETED. Normally called automatically by register_from_appointment, but can be used manually.

with studio.session() as s:
    studio.appointments(s).complete("appt_id_123")

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.mark_no_show(appointment_id)

Marks an appointment as NO_SHOW — the client did not show up.

with studio.session() as s:
    studio.appointments(s).mark_no_show("appt_id_123")

---

.list_upcoming()

Returns all future appointments in SCHEDULED status, ordered by date.

with studio.session() as s:
    upcoming = studio.appointments(s).list_upcoming()
    for appt in upcoming:
        print(f"{appt.scheduled_at}  —  {appt.service.name}")

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.list_by_date(date)

Returns all appointments on a given day.

with studio.session() as s:
    today = studio.appointments(s).list_by_date(datetime.now())

---

.list_by_client(client_id)

Returns all appointments for a given client, ordered by date descending.

with studio.session() as s:
    appts = studio.appointments(s).list_by_client("client_id_1")

---

.list_by_provider(provider_id)

Returns all appointments for a given provider, ordered by date descending.

with studio.session() as s:
    appts = studio.appointments(s).list_by_provider("provider_id_1")

---

.list_by_status(status)

Returns all appointments with a given status.

from gesta.core.entities import AppointmentStatus

with studio.session() as s:
    cancelled = studio.appointments(s).list_by_status(AppointmentStatus.CANCELLED)

---

TransactionManager — studio.transactions(session)

Manages the registration of services delivered and products sold.

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.register(offering_id, client_ids, occurred_at, provider_ids=None, amount=None, cost_amount=None, notes=None)

Registers a direct transaction without a prior appointment. Useful for spontaneous product sales or walk-in services.

If amount is not provided, it is calculated as offering.price × number of clients. If cost_amount is not provided, it is calculated as offering.cost × number of clients.

Parameter	Type	Description
offering_id	str	ID of the service or product
client_ids	list[str]	IDs of clients
occurred_at	datetime	When the service was delivered or product sold
provider_ids	list[str]	IDs of providers (optional for products)
amount	Decimal	Override the calculated amount (e.g. for discounts)
cost_amount	Decimal	Override the calculated cost
notes	str	Optional notes

from datetime import datetime
from decimal import Decimal

with studio.session() as s:
    # Product sale — no provider needed
    tx = studio.transactions(s).register(
        offering_id = "prd_aceite_lavanda",
        client_ids  = ["client_id_1"],
        occurred_at = datetime.now(),
    )

    # Service with custom discount
    tx = studio.transactions(s).register(
        offering_id  = "svc_masaje_sueco",
        client_ids   = ["client_id_1"],
        provider_ids = ["provider_id_1"],
        occurred_at  = datetime.now(),
        amount       = Decimal("500.00"),  # discounted from $600
    )

    # Group class — amount calculated automatically
    # yoga $120/person × 3 clients = $360
    tx = studio.transactions(s).register(
        offering_id  = "svc_yoga_grupal",
        client_ids   = ["client_1", "client_2", "client_3"],
        provider_ids = ["instructor_id_1"],
        occurred_at  = datetime.now(),
    )
    print(tx.amount)           # Decimal('360.00')
    print(tx.price_per_client) # Decimal('120.00')
    print(tx.profit)           # amount - cost_amount

---

.register_from_appointment(appointment_id, occurred_at, amount=None, cost_amount=None, notes=None)

Registers a transaction from an existing appointment, inheriting its clients, providers, and service. Automatically marks the appointment as COMPLETED.

Raises ValidationError if the appointment is not in SCHEDULED status, and BusinessRuleError if it already has a transaction.

with studio.session() as s:
    tx = studio.transactions(s).register_from_appointment(
        appointment_id = "appt_id_123",
        occurred_at    = datetime.now(),
    )
    print(tx.amount)      # price × number of clients
    print(tx.cost_amount) # cost × number of clients
    print(tx.profit)      # amount - cost_amount

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.get(transaction_id)

Returns a transaction by ID. Raises NotFoundError if it doesn't exist.

with studio.session() as s:
    tx = studio.transactions(s).get("tx_id_123")
    print(f"Balance pending: ${tx.balance}")

---

.list_by_client(client_id)

Returns all transactions for a given client.

with studio.session() as s:
    txs = studio.transactions(s).list_by_client("client_id_1")

---

.list_by_provider(provider_id)

Returns all transactions for a given provider.

with studio.session() as s:
    txs = studio.transactions(s).list_by_provider("provider_id_1")

---

.list_by_date_range(start, end)

Returns all transactions within a date range.

with studio.session() as s:
    txs = studio.transactions(s).list_by_date_range(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 3, 31),
    )

---

.list_pending()

Returns all transactions with unpaid balance (PENDING status).

with studio.session() as s:
    pending = studio.transactions(s).list_pending()
    for tx in pending:
        print(f"{tx.id}  —  balance: ${tx.balance}")

---

PaymentManager — studio.payments(session)

Manages payments linked to one or more transactions.

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.register(transaction_ids, amount, method, paid_at, notes=None)

Registers a payment and links it to one or more transactions. Automatically updates the status of each transaction (PENDING → PARTIAL → PAID).

Parameter	Type	Description
transaction_ids	list[str]	IDs of transactions this payment covers
amount	Decimal	Amount paid
method	PaymentMethod	CASH, CARD, TRANSFER, or OTHER
paid_at	datetime	When the payment was received
notes	str	Optional notes

from decimal import Decimal
from datetime import datetime
from gesta.core.entities import PaymentMethod

with studio.session() as s:
    # Full payment — single transaction
    studio.payments(s).register(
        transaction_ids = ["tx_id_1"],
        amount          = Decimal("600.00"),
        method          = PaymentMethod.CASH,
        paid_at         = datetime.now(),
    )

    # Partial payment
    studio.payments(s).register(
        transaction_ids = ["tx_id_1"],
        amount          = Decimal("300.00"),
        method          = PaymentMethod.CARD,
        paid_at         = datetime.now(),
        notes           = "First installment",
    )

    # One payment covers two transactions at once
    studio.payments(s).register(
        transaction_ids = ["tx_id_1", "tx_id_2"],
        amount          = Decimal("780.00"),
        method          = PaymentMethod.TRANSFER,
        paid_at         = datetime.now(),
    )

---

.register_refund(transaction_ids, amount, method, paid_at, notes=None)

Registers a refund against one or more transactions. Marks each transaction as REFUNDED.

with studio.session() as s:
    studio.payments(s).register_refund(
        transaction_ids = ["tx_id_1"],
        amount          = Decimal("600.00"),
        method          = PaymentMethod.CASH,
        paid_at         = datetime.now(),
        notes           = "Client was unsatisfied",
    )

---

.get(payment_id)

Returns a payment by ID. Raises NotFoundError if it doesn't exist.

with studio.session() as s:
    payment = studio.payments(s).get("pay_id_123")
    print(payment.method)
    print(payment.amount)

---

.list_by_transaction(transaction_id)

Returns all payments associated with a transaction.

with studio.session() as s:
    payments = studio.payments(s).list_by_transaction("tx_id_1")

---

.list_by_method(method)

Returns all payments by payment method.

from gesta.core.entities import PaymentMethod

with studio.session() as s:
    cash_payments = studio.payments(s).list_by_method(PaymentMethod.CASH)

---

.list_by_date_range(start, end)

Returns all payments within a date range.

with studio.session() as s:
    payments = studio.payments(s).list_by_date_range(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 1, 31),
    )

---

ReportManager — studio.reports(session)

Generates financial summaries and business metrics. Read-only — never writes data.

---

.revenue_summary(start, end)

Returns a RevenueSummary with full financial breakdown for a period.

Field	Description
total_revenue	Sum of all transaction amounts
total_cost	Sum of all transaction costs
total_profit	total_revenue - total_cost
total_collected	Sum of payments actually received
total_pending	Sum of unpaid balances
by_method	Dict of collected amounts per payment method
transaction_count	Number of transactions
payment_count	Number of payments
profit_margin	Profit as a percentage of revenue

with studio.session() as s:
    summary = studio.reports(s).revenue_summary(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
    )
    print(f"Revenue:  ${summary.total_revenue}")
    print(f"Profit:   ${summary.total_profit}")
    print(f"Margin:   {summary.profit_margin}%")
    print(f"Pending:  ${summary.total_pending}")
    print(f"By method: {summary.by_method}")
    # {'cash': Decimal('1200.00'), 'card': Decimal('840.00')}

---

.monthly_summary(year, month)

Shortcut for revenue_summary scoped to a single month.

with studio.session() as s:
    summary = studio.reports(s).monthly_summary(year=2025, month=3)
    print(f"March revenue: ${summary.total_revenue}")

---

.daily_revenue(start, end)

Returns a dict of { 'YYYY-MM-DD': amount } for each day in the range.

with studio.session() as s:
    daily = studio.reports(s).daily_revenue(
        start = datetime(2025, 3, 1),
        end   = datetime(2025, 3, 31),
    )
    for day, amount in daily.items():
        print(f"{day}: ${amount}")

---

.most_popular_offerings(start, end, top=5)

Returns the top N most sold services/products in a period, ordered by transaction count.

Each result is an OfferingStats with offering_name, count, total_revenue, total_cost, total_profit, and profit_margin.

with studio.session() as s:
    top = studio.reports(s).most_popular_offerings(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
        top   = 3,
    )
    for item in top:
        print(f"{item.offering_name}: {item.count}x — margin {item.profit_margin}%")

---

.most_frequent_clients(start, end, top=10)

Returns the top N clients by number of transactions. Each result is a PersonStats with person_name, transaction_count, and total_spent.

with studio.session() as s:
    clients = studio.reports(s).most_frequent_clients(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
        top   = 5,
    )
    for c in clients:
        print(f"{c.person_name}: {c.transaction_count} visits — spent ${c.total_spent}")

---

.most_active_providers(start, end, top=10)

Returns the top N providers by number of transactions. Each result is a PersonStats with person_name, transaction_count, and total_generated.

with studio.session() as s:
    providers = studio.reports(s).most_active_providers(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
    )
    for p in providers:
        print(f"{p.person_name}: {p.transaction_count} sessions — generated ${p.total_generated}")

---

.appointment_summary(start, end)

Returns an AppointmentSummary with counts per status and completion rate.

Field	Description
scheduled	Appointments still pending
completed	Appointments completed
cancelled	Appointments cancelled
no_show	Appointments where client didn't show
total	Total appointments (property)
completion_rate	Percentage of completed vs total (property)

with studio.session() as s:
    summary = studio.reports(s).appointment_summary(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
    )
    print(f"Completed:       {summary.completed}/{summary.total}")
    print(f"Completion rate: {summary.completion_rate}%")
    print(f"No-shows:        {summary.no_show}")

---

.export_transactions_to_dict(start, end)

Exports transactions in a period as a list of dicts, ready to convert to CSV or JSON.

import json, csv

with studio.session() as s:
    rows = studio.reports(s).export_transactions_to_dict(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
    )

# Export to JSON
with open("transactions.json", "w") as f:
    json.dump(rows, f, indent=2)

# Export to CSV
with open("transactions.csv", "w", newline="") as f:
    writer = csv.DictWriter(f, fieldnames=rows[0].keys())
    writer.writeheader()
    writer.writerows(rows)

---

.export_payments_to_dict(start, end)

Exports payments in a period as a list of dicts.

with studio.session() as s:
    rows = studio.reports(s).export_payments_to_dict(
        start = datetime(2025, 1, 1),
        end   = datetime(2025, 12, 31),
    )

---

WellnessStudio — gesta.extensions.WellnessStudio

A ready-to-use extension of Gesta for integral wellness businesses. Preloads roles, sample services, and sample products.

---

WellnessStudio(db_url, echo=False)

Same as Gesta, with wellness-specific setup.

from gesta.extensions import WellnessStudio

studio = WellnessStudio(db_url="sqlite:///wellness.db")

---

.setup(load_sample_data=True)

Initializes roles and optionally loads sample services and products. Safe to call multiple times — never duplicates records.

Set load_sample_data=False for production to load only roles.

studio.setup()                          # loads roles + sample data
studio.setup(load_sample_data=False)    # loads roles only

Predefined roles: client, therapist, instructor, admin

Sample services: Swedish massage, hot stone massage, group yoga, meditation session, holistic therapy

Sample products: Lavender essential oil, sandalwood incense, aromatic candle, relaxing herb mix

---

.add_client(session, name, phone=None, email=None, notes=None)

Registers a new person with the client role. Raises DuplicateError if the email already exists.

with studio.session() as s:
    client = studio.add_client(
        s,
        name  = "Ana García",
        phone = "5551234567",
        email = "[e-mail]",
    )
    print(client.id)

---

.add_provider(session, name, role, phone=None, email=None, notes=None)

Registers a new person with a provider role (therapist, instructor, or admin). Raises DuplicateError if the email already exists, and InvalidRoleError if the role is not a provider role.

with studio.session() as s:
    therapist = studio.add_provider(
        s,
        name  = "Marta López",
        role  = "therapist",
        email = "[e-mail]",
    )

---

.list_clients(session)

Returns all active people with the client role, ordered by name.

with studio.session() as s:
    clients = studio.list_clients(s)
    for c in clients:
        print(c.name)

---

.list_providers(session)

Returns all active people with a provider role, ordered by name.

with studio.session() as s:
    providers = studio.list_providers(s)

---

Exceptions

All exceptions inherit from GestaError and can be caught individually or as a group.

Exception	When it's raised
ValidationError	Invalid data — negative amount, past date, empty required field
AppointmentConflictError	Provider already has an appointment in the requested time slot
NotFoundError	Entity not found in the database
DuplicateError	Unique constraint violation — e.g. duplicate email
BusinessRuleError	Business rule violation — e.g. cancelling an appointment that has a transaction
UnpaidTransactionError	Operation requires a paid transaction but balance is pending
InactiveOfferingError	Trying to book or sell an inactive service or product
NoProviderError	Service requires a provider but none was assigned
InvalidRoleError	Person does not have the required role
DatabaseError	Connection or database operation failure

from gesta import (
    NotFoundError,
    AppointmentConflictError,
    ValidationError,
    GestaError,
)

try:
    with studio.session() as s:
        studio.appointments(s).book(...)

except AppointmentConflictError as e:
    print(f"Schedule conflict: {e}")

except ValidationError as e:
    print(f"Invalid data: {e}")

except NotFoundError as e:
    print(f"{e.entity} not found: {e.identifier}")

except GestaError as e:
    # Catches any Gesta exception
    print(f"Gesta error: {e}")

---

Extending Gesta

Gesta is designed to adapt to any appointment-based business. Create your own extension by subclassing Gesta:

from gesta import Gesta
from gesta.core.entities import Role

class HairSalon(Gesta):
    def setup(self):
        with self.session() as s:
            roles = [
                Role(id="role_client",  name="client",  is_recipient=True,  is_provider=False),
                Role(id="role_stylist", name="stylist", is_recipient=False, is_provider=True),
            ]
            for role in roles:
                if not s.get(Role, role.id):
                    s.add(role)

salon = HairSalon(db_url="sqlite:///salon.db")
salon.setup()

---

Using with PostgreSQL

studio = WellnessStudio(
    db_url="postgresql://user:password@localhost/gesta_db"
)

Install the PostgreSQL driver:

pip install psycopg2-binary

---

Running tests

pip install pytest
pytest tests/ -v

---

Docker

# Build
docker build -t gesta .

# Run demo
docker run --rm gesta

# Run tests
docker run --rm gesta python -m pytest tests/ -v

# Interactive shell
docker run --rm -it gesta bash

---

Project structure

gesta/
├── gesta/
│   ├── __init__.py
│   ├── gesta.py                # Main Gesta class
│   ├── core/
│   │   ├── entities.py         # Person, Role, Offering, Appointment, Transaction, Payment
│   │   ├── database.py         # Engine, session, init_db
│   │   ├── exceptions.py       # Custom exceptions
│   │   └── validators.py       # Reusable validation functions
│   ├── managers/
│   │   ├── calendar.py         # AppointmentManager
│   │   ├── transactions.py     # TransactionManager, PaymentManager
│   │   └── reports.py          # ReportManager
│   └── extensions/
│       └── wellness.py         # WellnessStudio — example extension
├── tests/
├── scripts/
│   └── demo.py
├── Dockerfile
├── pyproject.toml
└── README.md

---

License

MIT license — see LICENSE for details.