go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/server/tq/txn/spanner/init.go (about)

     1  // Copyright 2020 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Spanner contains Transactional Enqueue support for Cloud Spanner.
    16  //
    17  // Importing this package adds Cloud Spanner transactions support to server/tq's
    18  // AddTask. Works only for transactions initiated via server/span library
    19  // (see ReadWriteTransaction there).
    20  //
    21  // This package is normally imported unnamed:
    22  //
    23  //	import _ "go.chromium.org/luci/server/tq/txn/spanner"
    24  package spanner
    25  
    26  import (
    27  	"context"
    28  
    29  	"go.chromium.org/luci/server/span"
    30  	"go.chromium.org/luci/server/tq/internal/db"
    31  	"go.chromium.org/luci/server/tq/internal/lessor"
    32  )
    33  
    34  var impl spanDB
    35  
    36  func init() {
    37  	db.Register(db.Impl{
    38  		Kind:   impl.Kind(),
    39  		Module: span.ModuleName,
    40  		ProbeForTxn: func(ctx context.Context) db.DB {
    41  			if span.RW(ctx) != nil {
    42  				return impl
    43  			}
    44  			return nil
    45  		},
    46  		NonTxn: func(ctx context.Context) db.DB {
    47  			return impl
    48  		},
    49  	})
    50  }
    51  
    52  func init() {
    53  	lessor.Register("spanner", func(context.Context) (lessor.Lessor, error) {
    54  		return &spanLessor{}, nil
    55  	})
    56  }