Initial checkin

.gitignore

@@ -0,0 +1,3 @@
+# Generated with m4
+version.go
+.version*

Makefile

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+PACKAGE = gitlab.weird-web-workers.org/golang/logger
+
+SOURCES = version.go \
+	  logger.go \
+	  message.go
+
+VERSION = 0.0.1
+REVISION = $(shell git rev-parse HEAD)
+BUILDTIME= "$(shell date -u +'%Y-%m-%dT%H:%M:%SZ')"
+
+GOOS = $(shell go env GOOS)
+GOARCH = $(shell go env GOARCH)
+
+LIBRARY = $(GOPATH)/pkg/$(GOOS)_$(GOARCH)/$(PACKAGE).a
+
+.PHONY: all clean .version
+
+all: $(LIBRARY)
+
+$(LIBRARY): $(SOURCES)
+	go install $(PACKAGE)
+
+.version:
+	-@printf "%s\n%s\n%s" \
+		"$(VERSION)" "$(REVISION)" "$(BUILDTIME)" >$@.new
+	-@diff $@ $@.new >/dev/null 2>&1 && rm $@.new || mv $@.new $@
+
+version.go: version.go.m4 .version
+	-@m4 -Dm4_version=$(VERSION) \
+	   -Dm4_revision=$(REVISION) \
+	   -Dm4_build_time=$(BUILDTIME) \
+	   $< >$@
+
+clean:
+	-@rm -f version.go 2>/dev/null
+	-@rm -f .version 2>/dev/null
+	-@rm -f $(LIBRARY) 2>/dev/null

logger.go

@@ -0,0 +1,162 @@
+/*
+Handle the applications logging needs/
+
+Authors:
+Georg Hopp <georg@steffers.org>
+
+Changes:
+2018-10-02 [Georg Hopp] File created.
+
+Copyright © 2018 Georg Hopp
+
+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 3 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
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"time"
+)
+
+type Severity int
+
+const (
+	DEBUG Severity = iota
+	INFO
+	WARNING
+	ERROR
+	FATAL
+)
+
+var (
+	SevStrings = [...]string{
+		"DEBUG",
+		"INFO",
+		"WARNING",
+		"ERROR",
+		"FATAL",
+	}
+)
+
+type Logger struct {
+	logLevel Severity
+	name     string
+}
+
+var Default = GetLogger(INFO, "default")
+
+func GetLogger(sev Severity, name string) *Logger {
+	logger := Logger{sev, name}
+	return &logger
+}
+
+func SevStringToSeverity(sevStr string) (sev Severity) {
+	switch sevStr {
+	case SevStrings[DEBUG]:
+		sev = DEBUG
+	case SevStrings[INFO]:
+		sev = INFO
+	case SevStrings[WARNING]:
+		sev = WARNING
+	case SevStrings[FATAL]:
+		sev = FATAL
+	case SevStrings[ERROR]:
+		fallthrough
+	default:
+		sev = ERROR
+	}
+	return
+}
+
+func SeverityToSevString(sev Severity) string {
+	return SevStrings[sev]
+}
+
+func (logger *Logger) SetLevel(level Severity) {
+	logger.logLevel = level
+}
+
+func (logger *Logger) logToJson(
+	sev Severity, format string, args ...interface{}) string {
+
+	message, err := json.Marshal(
+		logMessage{
+			time.Now().UTC().Format(time.RFC3339),
+			logger.name,
+			sev,
+			fmt.Sprintf(format, args...),
+		})
+	if err != nil {
+		// TODO Making it fatal if no logging can be done is
+		// kind of drastic
+		os.Exit(1)
+	}
+	return string(message[:])
+}
+
+func (logger *Logger) log(sev Severity, format string, args ...interface{}) {
+
+	var output *os.File
+
+	if sev >= ERROR {
+		output = os.Stderr
+	} else {
+		output = os.Stdout
+	}
+
+	if sev >= logger.logLevel {
+		fmt.Fprintln(output, logger.logToJson(sev, format, args...))
+	}
+}
+
+func (logger *Logger) Debug(format string, args ...interface{}) {
+	logger.log(DEBUG, format, args...)
+}
+
+func (logger *Logger) Info(format string, args ...interface{}) {
+	logger.log(INFO, format, args...)
+}
+
+func (logger *Logger) Warning(format string, args ...interface{}) {
+	logger.log(WARNING, format, args...)
+}
+
+func (logger *Logger) Error(format string, args ...interface{}) {
+	logger.log(ERROR, format, args...)
+}
+
+func (logger *Logger) Panic(format string, args ...interface{}) {
+	logger.log(FATAL, format, args...)
+	panic(fmt.Sprintf(format, args...))
+}
+
+func (logger *Logger) LogError(
+	err error, format string, args ...interface{}) {
+
+	if err != nil {
+		logger.Error("%s: %s", fmt.Sprintf(format, args...), err)
+	}
+}
+
+func (logger *Logger) FailOnError(
+	err error, format string, args ...interface{}) {
+
+	if err != nil {
+		logger.Panic("%s: %s", fmt.Sprintf(format, args...), err)
+	}
+}
+
+// vim: ts=4 sts=4 sw=4 noet tw=72:

message.go

@@ -0,0 +1,49 @@
+/*
+Handle the applications logging needs/
+
+Authors:
+Georg Hopp <georg@steffers.org>
+
+Changes:
+2018-10-02 [Georg Hopp] File created.
+
+Copyright © 2018 Georg Hopp
+
+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 3 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
+
+import (
+	"fmt"
+)
+
+type logMessage struct {
+	Time     string   `json:"time"`
+	Logger   string   `json:"logger"`
+	Severity Severity `json:"severity"`
+	Message  string   `json:"message"`
+}
+
+func (sev Severity) MarshalJSON() (data []byte, err error) {
+	if int(sev) > len(SevStrings)-1 {
+		data = nil
+		err = fmt.Errorf("Unable to marshal unknown severity: %d", sev)
+	} else {
+		data = []byte("\"" + SevStrings[sev] + "\"")
+		err = nil
+	}
+	return
+}
+
+// vim: ts=4 sts=4 sw=4 noet tw=72:

version.go.m4

@@ -0,0 +1,33 @@
+/*
+Package version information.
+
+Authors:
+Georg Hopp <georg@steffers.org>
+
+Changes:
+2018-10-02 [Georg Hopp] File created.
+
+Copyright © 2018 Georg Hopp
+
+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 3 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 test
+
+const (
+	VERSION = "m4_version"
+	REVISION = "m4_revision"
+	BUILD_TIME = "m4_build_time"
+)
+
+// vim: ts=4 sts=4 sw=4 noet tw=72: