From 88f20d488039dcf445748b0d19af492bd0d21997 Mon Sep 17 00:00:00 2001
From: Ben Meier <ben.meier@humanitec.com>
Date: Fri, 10 May 2024 12:28:21 +0100
Subject: [PATCH] feat: added version and logging levels

---
 internal/logging/logging.go | 53 +++++++++++++++++++++++++++++++++++++
 internal/version/version.go | 48 +++++++++++++++++++++++++++++++++
 main.go                     | 31 +++++++++++++++++++++-
 3 files changed, 131 insertions(+), 1 deletion(-)
 create mode 100644 internal/logging/logging.go
 create mode 100644 internal/version/version.go

diff --git a/internal/logging/logging.go b/internal/logging/logging.go
new file mode 100644
index 0000000..fd9af9b
--- /dev/null
+++ b/internal/logging/logging.go
@@ -0,0 +1,53 @@
+// Copyright 2024 Humanitec
+//
+// 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 logging
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log/slog"
+	"sync"
+)
+
+type SimpleHandler struct {
+	Writer io.Writer
+	Level  slog.Leveler
+
+	mu sync.Mutex
+}
+
+func (h *SimpleHandler) Enabled(ctx context.Context, level slog.Level) bool {
+	return level >= h.Level.Level()
+}
+
+func (h *SimpleHandler) Handle(ctx context.Context, record slog.Record) error {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	_, err := h.Writer.Write([]byte(fmt.Sprintf("%s: %s\n", record.Level.String(), record.Message)))
+	return err
+}
+
+func (h *SimpleHandler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	// no support for attrs here
+	return h
+}
+
+func (h *SimpleHandler) WithGroup(name string) slog.Handler {
+	// no support for attrs here
+	return h
+}
+
+var _ slog.Handler = (*SimpleHandler)(nil)
diff --git a/internal/version/version.go b/internal/version/version.go
new file mode 100644
index 0000000..6836a09
--- /dev/null
+++ b/internal/version/version.go
@@ -0,0 +1,48 @@
+// Copyright 2024 Humanitec
+//
+// 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 version
+
+import (
+	"fmt"
+	"runtime/debug"
+)
+
+var (
+	Version string = "0.0.0"
+)
+
+// BuildVersionString constructs a version string by looking at the build metadata injected at build time.
+// This is particularly useful when score-compose is stilled from the go module using go install.
+func BuildVersionString() string {
+	versionNumber, buildTime, gitSha, isDirtySuffix := Version, "local", "unknown", ""
+	if info, ok := debug.ReadBuildInfo(); ok {
+		if info.Main.Version != "" && info.Main.Version != "(devel)" {
+			versionNumber = info.Main.Version
+		}
+		for _, setting := range info.Settings {
+			switch setting.Key {
+			case "vcs.time":
+				buildTime = setting.Value
+			case "vcs.revision":
+				gitSha = setting.Value
+			case "vcs.modified":
+				if setting.Value == "true" {
+					isDirtySuffix = "-dirty"
+				}
+			}
+		}
+	}
+	return fmt.Sprintf("%s (build: %s, sha: %s%s)", versionNumber, buildTime, gitSha, isDirtySuffix)
+}
diff --git a/main.go b/main.go
index e95a6f1..ee4225e 100644
--- a/main.go
+++ b/main.go
@@ -16,18 +16,47 @@ package main
 
 import (
 	"fmt"
+	"io"
+	"log/slog"
 	"os"
 
 	"github.com/spf13/cobra"
+
+	"github.com/score-spec/score-k8s/internal/logging"
+	"github.com/score-spec/score-k8s/internal/version"
 )
 
 var rootCmd = &cobra.Command{
-	Use:           "score-k8s",
+	Use:   "score-k8s",
+	Short: "Score to Kubernetes manifest translator",
+	Long: `Score is a specification for defining environment agnostic configuration for cloud based workloads.
+This tool produces a file of Kubernetes manifests from the Score specification.`,
 	SilenceErrors: true,
+
+	// This function always runs for all subcommands
+	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+		if q, _ := cmd.Flags().GetBool("quiet"); q {
+			slog.SetDefault(slog.New(&logging.SimpleHandler{Level: slog.LevelError, Writer: io.Discard}))
+		} else if v, _ := cmd.Flags().GetCount("verbose"); v == 0 {
+			slog.SetDefault(slog.New(&logging.SimpleHandler{Level: slog.LevelInfo, Writer: cmd.ErrOrStderr()}))
+		} else if v == 1 {
+			slog.SetDefault(slog.New(&logging.SimpleHandler{Level: slog.LevelDebug, Writer: cmd.ErrOrStderr()}))
+		} else if v == 2 {
+			slog.SetDefault(slog.New(slog.NewTextHandler(cmd.ErrOrStderr(), &slog.HandlerOptions{
+				Level: slog.LevelDebug, AddSource: true,
+			})))
+		}
+		return nil
+	},
 }
 
 func init() {
+	rootCmd.Version = version.BuildVersionString()
+	rootCmd.SetVersionTemplate(`{{with .Name}}{{printf "%s " .}}{{end}}{{printf "%s" .Version}}
+`)
 	rootCmd.CompletionOptions = cobra.CompletionOptions{HiddenDefaultCmd: true}
+	rootCmd.PersistentFlags().Bool("quiet", false, "Mute any logging output")
+	rootCmd.PersistentFlags().CountP("verbose", "v", "Increase log verbosity and detail by specifying this flag one or more times")
 }
 
 func main() {