[obitools] Add validation for paired files and config template support

- Enforce requirement of both forward (-F) and reverse files in obipairing/main.go
- Add config template support to obtagpcr via CLIAskConfigTemplate()
- Remove redundant Required() constraints in options.go
- Introduce new helper CLIHasPairedFiles()

cmd/obitools/obipairing/main.go

@@ -37,6 +37,11 @@ func main() {
 
 	optionParser(os.Args)
 
+	if !obipairing.CLIHasPairedFiles() {
+		log.Error("You must provide both a forward file (-F) and a reverse file (-R)")
+		os.Exit(1)
+	}
+
 	obidefault.SetStrictReadWorker(2)
 	obidefault.SetStrictWriteWorker(2)
 	pairs, err := obipairing.CLIPairedSequence()

cmd/obitools/obitagpcr/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"os"
 
 	log "github.com/sirupsen/logrus"
@@ -8,6 +9,7 @@ import (
 	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obidefault"
 	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obioptions"
 	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obitools/obiconvert"
+	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obitools/obimultiplex"
 	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obitools/obipairing"
 	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obitools/obitagpcr"
 	"git.metabarcoding.org/obitools/obitools4/obitools4/pkg/obiutils"
@@ -39,6 +41,17 @@ func main() {
 		obitagpcr.OptionSet)
 
 	optionParser(os.Args)
+
+	if obimultiplex.CLIAskConfigTemplate() {
+		fmt.Print(obimultiplex.CLIConfigTemplate())
+		os.Exit(0)
+	}
+
+	if !obipairing.CLIHasPairedFiles() {
+		log.Error("You must provide both a forward file (-F) and a reverse file (-R)")
+		os.Exit(1)
+	}
+
 	pairs, err := obipairing.CLIPairedSequence()
 
 	if err != nil {

pkg/obitools/obipairing/options.go

@@ -21,12 +21,10 @@ func PairingOptionSet(options *getoptions.GetOpt) {
 	options.StringVar(&_ForwardFile, "forward-reads", "",
 		options.Alias("F"),
 		options.ArgName("FILENAME_F"),
-		options.Required("You must provide at a forward file"),
 		options.Description("The file names containing the forward reads"))
 	options.StringVar(&_ReverseFile, "reverse-reads", "",
 		options.Alias("R"),
 		options.ArgName("FILENAME_R"),
-		options.Required("You must provide a reverse file"),
 		options.Description("The file names containing the reverse reads"))
 	options.IntVar(&_Delta, "delta", _Delta,
 		options.Alias("D"),
@@ -72,6 +70,10 @@ func CLIPairedSequence() (obiiter.IBioSequence, error) {
 	return paired, nil
 }
 
+func CLIHasPairedFiles() bool {
+	return _ForwardFile != "" && _ReverseFile != ""
+}
+
 func CLIDelta() int {
 	return _Delta
 }