johannaojeling commented on code in PR #25809: URL: https://github.com/apache/beam/pull/25809#discussion_r1147851156
########## sdks/go/pkg/beam/io/fileio/match.go: ########## @@ -0,0 +1,174 @@ +// 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 fileio provides transforms for matching and reading files. +package fileio + +import ( + "context" + "fmt" + "strings" + + "github.com/apache/beam/sdks/v2/go/pkg/beam" + "github.com/apache/beam/sdks/v2/go/pkg/beam/io/filesystem" + "github.com/apache/beam/sdks/v2/go/pkg/beam/register" +) + +func init() { + register.DoFn3x1[context.Context, string, func(filesystem.FileMetadata), error](&matchFn{}) + register.Emitter1[filesystem.FileMetadata]() +} + +// EmptyMatchTreatment controls how empty matches of a pattern are treated. +type EmptyMatchTreatment int + +const ( + // EmptyMatchTreatmentAllow allows empty matches. + EmptyMatchTreatmentAllow EmptyMatchTreatment = iota + // EmptyMatchTreatmentDisallow disallows empty matches. + EmptyMatchTreatmentDisallow + // EmptyMatchTreatmentAllowIfWildcard allows empty matches if the pattern contains a wildcard. + EmptyMatchTreatmentAllowIfWildcard +) + +type matchOption struct { + EmptyMatchTreatment EmptyMatchTreatment +} + +// MatchOptionFn is a function that can be passed to MatchFiles or MatchAll to configure options for +// matching files. +type MatchOptionFn func(*matchOption) error + +// WithEmptyMatchTreatment specifies how empty matches of a pattern should be treated. By default, +// empty matches are allowed if the pattern contains a wildcard. +func WithEmptyMatchTreatment(treatment EmptyMatchTreatment) MatchOptionFn { Review Comment: Apologies for the delay, it's now been updated with a suggestion. I like the way of providing the functional options without exporting the enums, it looks it simpler for the user. I do find naming of the option functions a bit tricky though, with regards to making it easy to tell which option fns are applicable to which function (for autocompletion as you mention etc.) without giving them too long names. I ended up using a naming convention with a prefix indicating which function it can be passed to (e.g. `Read`), followed by the type of configuration (`Compression`), followed by the value (`Gzip`). Do let me know if you still find it too verbose. My reason for prefixing them with `Match` and `Read` is to take into account the possibility that there could be other transforms added to the fileio package in the future, which may have some type of configuration that partly overlaps with that of other transforms. For example, what if we add a `Write` transform which can be configured with ```go type writeOption struct { Compression compressionType NumShards int } type WriteOptionFn func(*writeOption) ``` Configuring a compression is also applicable to `ReadOptionFn`, so we would need one function for each of these, i.e. `fileio.WriteCompressionGzip()` and `fileio.ReadCompressionGzip()`. I tried some solution with generics some time (similar to [this one](https://golang.design/research/generic-option/#:~:text=Using%20Generics%20(and%20Make%20Call%20Safer))), but found it cumbersome and that it put a burden on the user to select the right type. If you can think of a better way of doing it, I'm happy to change! -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
