🎨 Introduce contextualized logging

This commit is multi-fold as it also refactors internally context and logger
as interfaces so it is easier to plug luet as a library externally.

Introduces a garbage collector (related to #227) but doesn't handle yet
parallelism.

Closes #265

pkg/api/core/logger/logger_test.go

@@ -0,0 +1,131 @@
+// Copyright © 2021 Ettore Di Giacinto <mudler@gentoo.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, see <http://www.gnu.org/licenses/>.
+
+package logger_test
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/gookit/color"
+	"github.com/mudler/luet/pkg/api/core/logger"
+	. "github.com/mudler/luet/pkg/api/core/logger"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func captureStdout(f func(w io.Writer)) string {
+	originalStdout := os.Stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+	color.SetOutput(w)
+	f(w)
+
+	_ = w.Close()
+	out, _ := ioutil.ReadAll(r)
+	os.Stdout = originalStdout
+	color.SetOutput(os.Stdout)
+
+	_ = r.Close()
+
+	return string(out)
+}
+
+var _ = Describe("Context and logging", func() {
+
+	Context("Context", func() {
+		It("detect if is a terminal", func() {
+			Expect(captureStdout(func(w io.Writer) {
+				_, _, err := GetTerminalSize()
+				Expect(err).To(HaveOccurred())
+				Expect(err.Error()).To(Equal("size not detectable"))
+				os.Stdout.Write([]byte(err.Error()))
+			})).To(ContainSubstring("size not detectable"))
+		})
+
+		It("respects loglevel", func() {
+
+			l, err := New(WithLevel("info"))
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Debug("")
+			})).To(Equal(""))
+
+			l, err = New(WithLevel("debug"))
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Debug("foo")
+			})).To(ContainSubstring("foo"))
+		})
+
+		It("logs with context", func() {
+			l, err := New(WithLevel("debug"), WithContext("foo"))
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Debug("bar")
+			})).To(ContainSubstring("(foo)  bar"))
+		})
+
+		It("returns copies with logged context", func() {
+			l, err := New(WithLevel("debug"))
+			l, _ = l.Copy(logger.WithContext("bazzz"))
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Debug("bar")
+			})).To(ContainSubstring("(bazzz)  bar"))
+		})
+
+		It("logs to file", func() {
+
+			t, err := ioutil.TempFile("", "tree")
+			Expect(err).ToNot(HaveOccurred())
+			defer os.RemoveAll(t.Name()) // clean up
+
+			l, err := New(WithLevel("debug"), WithFileLogging(t.Name(), ""))
+			Expect(err).ToNot(HaveOccurred())
+
+			//	ctx.Init()
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Info("foot")
+			})).To(And(ContainSubstring("INFO"), ContainSubstring("foot")))
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Success("test")
+			})).To(And(ContainSubstring("SUCCESS"), ContainSubstring("test")))
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Error("foobar")
+			})).To(And(ContainSubstring("ERROR"), ContainSubstring("foobar")))
+
+			Expect(captureStdout(func(w io.Writer) {
+				l.Warning("foowarn")
+			})).To(And(ContainSubstring("WARNING"), ContainSubstring("foowarn")))
+
+			ll, err := ioutil.ReadFile(t.Name())
+			Expect(err).ToNot(HaveOccurred())
+			logs := string(ll)
+			Expect(logs).To(ContainSubstring("foot"))
+			Expect(logs).To(ContainSubstring("test"))
+			Expect(logs).To(ContainSubstring("foowarn"))
+			Expect(logs).To(ContainSubstring("foobar"))
+		})
+	})
+})