new(pkg/options): add the options packages

The options packags handles all the commons flags and configuration.
Having the common options managed in one place we avoid duplicated
logics in each command that uses the same flags.

Signed-off-by: Aldo Lacuku <[email protected]>

Author: alacuku

pkg/options/doc.go

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+// Copyright 2022 The Falco 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 options implements the generic logic to manage the common options
+// shared by all the falcoctl commands.
+package options

pkg/options/options.go

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+// Copyright 2022 The Falco 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 options
+
+import (
+	"io"
+
+	"github.com/spf13/pflag"
+
+	"github.com/falcosecurity/falcoctl/pkg/output"
+)
+
+// Used to store the verbose flag, and then passed to the printer.
+var verbose bool
+
+// ConfigOptions provides the common flags, options, and printers for all the
+// commands. All the fields provided by the ConfigOptions will be initialized before
+// the commands are executed through the Initialize func.
+type ConfigOptions struct {
+	// Printer used by all commands to output messages.
+	Printer *output.Printer
+	// printerScope contains the data of the optional scope of a prefix.
+	// It used to add a prefix to the output of a printer.
+	printerScope string
+	// writer is used to write the output of the printer.
+	writer io.Writer
+}
+
+// NewOptions returns a new ConfigOptions struct.
+func NewOptions() *ConfigOptions {
+	return &ConfigOptions{}
+}
+
+// Configs type of the configs accepted by the Initialize function.
+type Configs func(options *ConfigOptions)
+
+// WithPrinterScope sets the scope for the printer.
+func WithPrinterScope(scope string) Configs {
+	return func(options *ConfigOptions) {
+		options.printerScope = scope
+	}
+}
+
+// WithWriter sets the writer for the printer.
+func WithWriter(writer io.Writer) Configs {
+	return func(options *ConfigOptions) {
+		options.writer = writer
+	}
+}
+
+// Initialize initializes the options based on the configs. Subsequent calls will overwrite the
+// previous configurations based on the new configs passed to the functions.
+func (o *ConfigOptions) Initialize(cfgs ...Configs) {
+	for _, cfg := range cfgs {
+		cfg(o)
+	}
+
+	// create the printer. The value of verbose is a flag value.
+	o.Printer = output.NewPrinter(o.printerScope, verbose, o.writer)
+}
+
+// AddFlags registers the common flags.
+func (o *ConfigOptions) AddFlags(flags *pflag.FlagSet) {
+	flags.BoolVarP(&verbose, "verbose", "v", false, "Enable verbose logs (default false)")
+}