sqlalchemy/alembic · error · Exception

No context has been configured yet.

Error message

No context has been configured yet.

What it means

Raised as a bare Exception by EnvironmentContext.get_context() (environment.py:1046-1056) when self._migration_context is None — meaning EnvironmentContext.configure() has not yet run. Almost every useful EnvironmentContext method (get_context, get_bind, run_migrations, begin_transaction) funnels through get_context(), so calling any of them pre-configure raises this.

Solutions

1. Ensure context.configure(connection=..., ...) runs before any context.get_bind()/get_context()/run_migrations() call.
2. In env.py, structure online mode as: if context.is_offline_mode(): run_offline; else: connect -> context.configure(connection=conn, ...) -> context.run_migrations().
3. If invoking migrations programmatically, call command.upgrade()/command.stamp() which configure the context for you.

Example fix

// before
def run_migrations_online():
    bind = context.get_bind()  # called before configure -> raises
    context.configure(connection=bind)
// after
def run_migrations_online():
    connectable = engine
    with connectable.connect() as connection:
        context.configure(connection=connection)
        with context.begin_transaction():
            context.run_migrations()

# Ensure configure() ran before touching context bindings.
def configured():
    from alembic.runtime.environment import EnvironmentContext
    return EnvironmentContext._migration_context is not None

if not configured():
    raise RuntimeError('Call context.configure(...) before get_bind()/run_migrations()')
bind = context.get_bind()

def context_is_configured(context) -> bool:
    return getattr(context, '_migration_context', None) is not None

When it happens

Trigger: Calling context.get_bind() or context.get_context() inside env.py before the `context.configure(...)` call; referencing `context` in a script that bypassed the standard env.py entry point; running a migration function that was imported and invoked directly without configuring the environment.

Common situations: Custom test harnesses that import env.py functions but never call configure(); env.py edited so configure() is conditional and skipped on a code path; multi-phase scripts that call get_bind() too early.

Related errors

• Connection, url, or dialect_name is required.
• A plugin named is already registered
• Can't drop table in batch mode
• constraint cannot be produced; original constraint is not…
• Constraint must have a name

AI-assisted analysis of sqlalchemy/alembic@5551b5d35f (2026-08-11). Data as JSON: /api/errors/5813f28553a2788f. Report an issue: GitHub.

Appendix: source

Thrown at alembic/runtime/environment.py:1055

        has more specific transactional needs can of course
        manipulate the :class:`~sqlalchemy.engine.Connection`
        directly to produce transactional state in "online"
        mode.

        """

        return self.get_context().begin_transaction()

    def get_context(self) -> MigrationContext:
        """Return the current :class:`.MigrationContext` object.

        If :meth:`.EnvironmentContext.configure` has not been
        called yet, raises an exception.

        """

        if self._migration_context is None:
            raise Exception("No context has been configured yet.")
        return self._migration_context

    def get_bind(self) -> Connection:
        """Return the current 'bind'.

        In "online" mode, this is the
        :class:`sqlalchemy.engine.Connection` currently being used
        to emit SQL to the database.

        This function requires that a :class:`.MigrationContext`
        has first been made available via :meth:`.configure`.

        """
        return self.get_context().bind  # type: ignore[return-value]

    def get_impl(self) -> DefaultImpl:
        return self.get_context().impl

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