introduce compose-spec command line for compose file validation

Signed-off-by: Nicolas De Loof <[email protected]>

cmd/main.go

@@ -0,0 +1,65 @@
+/*
+   Copyright 2020 The Compose Specification Authors.
+
+   Licensed 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 main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/compose-spec/compose-go/v2/cli"
+)
+
+func main() {
+	if len(os.Args) == 1 {
+		fmt.Println(`
+Validates a compose file conforms to the Compose Specification
+
+Usage: compose-spec [OPTIONS] COMPOSE_FILE [COMPOSE_OVERRIDE_FILE]
+`)
+	}
+
+	wd, err := os.Getwd()
+	if err != nil {
+		fmt.Errorf("can't determine current directory: %w", err)
+		os.Exit(1)
+	}
+
+	options, err := cli.NewProjectOptions(os.Args[1:],
+		cli.WithWorkingDirectory(wd),
+		cli.WithOsEnv,
+		cli.WithDotEnv,
+		cli.WithConfigFileEnv,
+		cli.WithDefaultConfigPath,
+	)
+	if err != nil {
+		fmt.Errorf("failed to configure project options: %w", err)
+		os.Exit(1)
+	}
+
+	project, err := cli.ProjectFromOptions(options)
+	if err != nil {
+		fmt.Errorf("failed to load project: %w", err)
+		os.Exit(1)
+	}
+
+	yaml, err := project.MarshalYAML()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "failed to marshall project: %w", err)
+		os.Exit(1)
+	}
+	fmt.Println(string(yaml))
+}