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Make set_unique operations respect the contract for old schema versions #118

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merged 3 commits into from
Sep 22, 2023
Merged

Make set_unique operations respect the contract for old schema versions #118

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0358e37
Update example migration to use up/down SQL
andrew-farries Sep 21, 2023
61563db
Duplicate and add triggers when setting `UNIQUE`
andrew-farries Sep 21, 2023
486ec86
Update tests for setting a column `UNIQUE`
andrew-farries Sep 21, 2023
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4 changes: 3 additions & 1 deletion examples/15_set_column_unique.json
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,9 @@
"column": "review",
"unique": {
"name": "reviews_review_unique"
}
},
"up": "review || '-' || (random()*1000000)::integer",
"down": "review"
}
}
]
Expand Down
4 changes: 3 additions & 1 deletion pkg/migrations/op_alter_column.go
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Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,7 @@ func (o *OpAlterColumn) Validate(ctx context.Context, s *schema.Schema) error {
// Apply any special validation rules for the inner operation
op := o.innerOperation()
switch op.(type) {
case *OpRenameColumn, *OpSetUnique:
case *OpRenameColumn:
if o.Up != "" {
return NoUpSQLAllowedError{}
}
Expand Down Expand Up @@ -126,6 +126,8 @@ func (o *OpAlterColumn) innerOperation() Operation {
Table: o.Table,
Column: o.Column,
Name: o.Unique.Name,
Up: o.Up,
Down: o.Down,
}
}
return nil
Expand Down
132 changes: 123 additions & 9 deletions pkg/migrations/op_set_unique.go
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Original file line number Diff line number Diff line change
Expand Up @@ -13,32 +13,136 @@ type OpSetUnique struct {
Name string `json:"name"`
Table string `json:"table"`
Column string `json:"column"`
Up string `json:"up"`
Down string `json:"down"`
}

var _ Operation = (*OpSetUnique)(nil)

func (o *OpSetUnique) Start(ctx context.Context, conn *sql.DB, stateSchema string, s *schema.Schema) error {
// create unique index concurrently
_, err := conn.ExecContext(ctx, fmt.Sprintf("CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS %s ON %s (%s)",
pq.QuoteIdentifier(o.Name),
pq.QuoteIdentifier(o.Table),
pq.QuoteIdentifier(o.Column)))
return err
table := s.GetTable(o.Table)
column := table.GetColumn(o.Column)

// create a copy of the column on the underlying table.
if err := duplicateColumn(ctx, conn, table, *column); err != nil {
return fmt.Errorf("failed to duplicate column: %w", err)
}

// Add a unique index to the new column
if err := o.addUniqueIndex(ctx, conn); err != nil {
return fmt.Errorf("failed to add unique index: %w", err)
}

// Add a trigger to copy values from the old column to the new, rewriting values using the `up` SQL.
err := createTrigger(ctx, conn, triggerConfig{
Name: TriggerName(o.Table, o.Column),
Direction: TriggerDirectionUp,
Columns: table.Columns,
SchemaName: s.Name,
TableName: o.Table,
PhysicalColumn: TemporaryName(o.Column),
StateSchema: stateSchema,
SQL: o.Up,
})
if err != nil {
return fmt.Errorf("failed to create up trigger: %w", err)
}

// Backfill the new column with values from the old column.
if err := backFill(ctx, conn, o.Table, TemporaryName(o.Column)); err != nil {
return fmt.Errorf("failed to backfill column: %w", err)
}

// Add the new column to the internal schema representation. This is done
// here, before creation of the down trigger, so that the trigger can declare
// a variable for the new column.
table.AddColumn(o.Column, schema.Column{
Name: TemporaryName(o.Column),
})

// Add a trigger to copy values from the new column to the old, rewriting values using the `down` SQL.
err = createTrigger(ctx, conn, triggerConfig{
Name: TriggerName(o.Table, TemporaryName(o.Column)),
Direction: TriggerDirectionDown,
Columns: table.Columns,
SchemaName: s.Name,
TableName: o.Table,
PhysicalColumn: o.Column,
StateSchema: stateSchema,
SQL: o.Down,
})
if err != nil {
return fmt.Errorf("failed to create down trigger: %w", err)
}

return nil
}

func (o *OpSetUnique) Complete(ctx context.Context, conn *sql.DB) error {
// create a unique constraint using the unique index
// Create a unique constraint using the unique index
_, err := conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE IF EXISTS %s ADD CONSTRAINT %s UNIQUE USING INDEX %s",
pq.QuoteIdentifier(o.Table),
pq.QuoteIdentifier(o.Name),
pq.QuoteIdentifier(o.Name)))
if err != nil {
return err
}

// Remove the up function and trigger
_, err = conn.ExecContext(ctx, fmt.Sprintf("DROP FUNCTION IF EXISTS %s CASCADE",
pq.QuoteIdentifier(TriggerFunctionName(o.Table, o.Column)),
))
if err != nil {
return err
}

// Remove the down function and trigger
_, err = conn.ExecContext(ctx, fmt.Sprintf("DROP FUNCTION IF EXISTS %s CASCADE",
pq.QuoteIdentifier(TriggerFunctionName(o.Table, TemporaryName(o.Column))),
))
if err != nil {
return err
}

// Drop the old column
_, err = conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE IF EXISTS %s DROP COLUMN IF EXISTS %s",
pq.QuoteIdentifier(o.Table),
pq.QuoteIdentifier(o.Column)))
if err != nil {
return err
}

// Rename the new column to the old column name
_, err = conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE IF EXISTS %s RENAME COLUMN %s TO %s",
pq.QuoteIdentifier(o.Table),
pq.QuoteIdentifier(TemporaryName(o.Column)),
pq.QuoteIdentifier(o.Column)))

return err
}

func (o *OpSetUnique) Rollback(ctx context.Context, conn *sql.DB) error {
// drop the index concurrently
_, err := conn.ExecContext(ctx, fmt.Sprintf("DROP INDEX CONCURRENTLY IF EXISTS %s", o.Name))
// Drop the new column, taking the unique index on the column with it
_, err := conn.ExecContext(ctx, fmt.Sprintf("ALTER TABLE %s DROP COLUMN IF EXISTS %s",
pq.QuoteIdentifier(o.Table),
pq.QuoteIdentifier(TemporaryName(o.Column)),
))
if err != nil {
return err
}

// Remove the up function and trigger
_, err = conn.ExecContext(ctx, fmt.Sprintf("DROP FUNCTION IF EXISTS %s CASCADE",
pq.QuoteIdentifier(TriggerFunctionName(o.Table, o.Column)),
))
if err != nil {
return err
}

// Remove the down function and trigger
_, err = conn.ExecContext(ctx, fmt.Sprintf("DROP FUNCTION IF EXISTS %s CASCADE",
pq.QuoteIdentifier(TriggerFunctionName(o.Table, TemporaryName(o.Column))),
))

return err
}
Expand All @@ -59,3 +163,13 @@ func (o *OpSetUnique) Validate(ctx context.Context, s *schema.Schema) error {

return nil
}

func (o *OpSetUnique) addUniqueIndex(ctx context.Context, conn *sql.DB) error {
// create unique index concurrently
_, err := conn.ExecContext(ctx, fmt.Sprintf("CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS %s ON %s (%s)",
pq.QuoteIdentifier(o.Name),
pq.QuoteIdentifier(o.Table),
pq.QuoteIdentifier(TemporaryName(o.Column))))

return err
}
37 changes: 28 additions & 9 deletions pkg/migrations/op_set_unique_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -52,19 +52,18 @@ func TestSetColumnUnique(t *testing.T) {
Unique: &migrations.UniqueConstraint{
Name: "reviews_review_unique",
},
Up: "review || '-' || (random()*1000000)::integer",
Down: "review",
},
},
},
},
afterStart: func(t *testing.T, db *sql.DB) {
// The unique index has been created on the underlying table.
IndexMustExist(t, db, "public", "reviews", "reviews_review_unique")

// Inserting values into the old schema that violate uniqueness should fail.
// Inserting values into the old schema that violate uniqueness should succeed.
MustInsert(t, db, "public", "01_add_table", "reviews", map[string]string{
"username": "alice", "product": "apple", "review": "good",
})
MustNotInsert(t, db, "public", "01_add_table", "reviews", map[string]string{
MustInsert(t, db, "public", "01_add_table", "reviews", map[string]string{
"username": "bob", "product": "banana", "review": "good",
})

Expand All @@ -77,12 +76,32 @@ func TestSetColumnUnique(t *testing.T) {
})
},
afterRollback: func(t *testing.T, db *sql.DB) {
// The unique index has been dropped from the the underlying table.
IndexMustNotExist(t, db, "public", "reviews", "reviews_review_unique")
// The new (temporary) `review` column should not exist on the underlying table.
ColumnMustNotExist(t, db, "public", "reviews", migrations.TemporaryName("review"))

// The up function no longer exists.
FunctionMustNotExist(t, db, "public", migrations.TriggerFunctionName("reviews", "review"))
// The down function no longer exists.
FunctionMustNotExist(t, db, "public", migrations.TriggerFunctionName("reviews", migrations.TemporaryName("review")))

// The up trigger no longer exists.
TriggerMustNotExist(t, db, "public", "reviews", migrations.TriggerName("reviews", "review"))
// The down trigger no longer exists.
TriggerMustNotExist(t, db, "public", "reviews", migrations.TriggerName("reviews", migrations.TemporaryName("review")))
},
afterComplete: func(t *testing.T, db *sql.DB) {
// The unique constraint has been created on the underlying table.
ConstraintMustExist(t, db, "public", "reviews", "reviews_review_unique")
// The new (temporary) `review` column should not exist on the underlying table.
ColumnMustNotExist(t, db, "public", "reviews", migrations.TemporaryName("review"))

// The up function no longer exists.
FunctionMustNotExist(t, db, "public", migrations.TriggerFunctionName("reviews", "review"))
// The down function no longer exists.
FunctionMustNotExist(t, db, "public", migrations.TriggerFunctionName("reviews", migrations.TemporaryName("review")))

// The up trigger no longer exists.
TriggerMustNotExist(t, db, "public", "reviews", migrations.TriggerName("reviews", "review"))
// The down trigger no longer exists.
TriggerMustNotExist(t, db, "public", "reviews", migrations.TriggerName("reviews", migrations.TemporaryName("review")))

// Inserting values into the new schema that violate uniqueness should fail.
MustInsert(t, db, "public", "02_set_unique", "reviews", map[string]string{
Expand Down