| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package beam |
| |
| import ( |
| "context" |
| "fmt" |
| |
| "github.com/apache/beam/sdks/go/pkg/beam/log" |
| ) |
| |
| // TODO(herohde) 7/6/2017: do we want to make the selected runner visible to |
| // transformations? That would allow runner-dependent operations or |
| // verification, but require that it is stored in Init and used for Run. |
| |
| var ( |
| runners = make(map[string]func(ctx context.Context, p *Pipeline) error) |
| ) |
| |
| // RegisterRunner associates the name with the supplied runner, making it available |
| // to execute a pipeline via Run. |
| func RegisterRunner(name string, fn func(ctx context.Context, p *Pipeline) error) { |
| if _, ok := runners[name]; ok { |
| panic(fmt.Sprintf("runner %v already defined", name)) |
| } |
| runners[name] = fn |
| } |
| |
| // Run executes the pipeline using the selected registred runner. It is customary |
| // to define a "runner" with no default as a flag to let users control runner |
| // selection. |
| func Run(ctx context.Context, runner string, p *Pipeline) error { |
| fn, ok := runners[runner] |
| if !ok { |
| log.Exitf(ctx, "Runner %v not registered. Forgot to _ import it?", runner) |
| } |
| return fn(ctx, p) |
| } |