feat: enable filtering console output by severity level

example/main.go

@@ -23,7 +23,13 @@ func main() {
 	main := fiber.New()
 
 	exps := make([]exporters.TraceExporter, 0)
-	exps = append(exps, exporters.DevConsoleExporter(console_exporter.ProcessorOptions{}))
+
+	envFilter := "OBSERVER_CONSOLE"
+
+	exps = append(exps, exporters.DevConsoleExporter(console_exporter.ProcessorOptions{
+		FilterFromEnvVar: &envFilter,
+	}))
+
 	gelfExp, err := exporters.GelfExporter()
 	if err == nil {
 		exps = append(exps, gelfExp)

pkg/exporters/console_exporter/console_exporter.go

@@ -3,6 +3,7 @@ package console_exporter
 import (
 	"context"
 	"fmt"
+	"os"
 	"slices"
 
 	"git.ma-al.com/maal-libraries/observer/pkg/attr"
@@ -22,7 +23,8 @@ type TraceFormatter interface {
 // Most of options are passed to the formatter.
 type ProcessorOptions struct {
 	// Try to parse filters from an environment variable with a name provided by this field.
-	// Result will only by applied to unset options. NOT IMPLEMENTED!
+	// Result will only by applied to unset options. Currently it will only attempt to parse
+	// severity level from the variable and use that as a filter.
 	FilterFromEnvVar *string
 	// Filter the output based on the [level.SeverityLevel].
 	FilterOnLevel level.SeverityLevel
@@ -79,9 +81,16 @@ func NewProcessor(opts ProcessorOptions) trace.SpanProcessor {
 		fmt := NewPrettyMultilineFormatter()
 		formatter = fmt
 	}
+	if opts.FilterFromEnvVar != nil {
+		envFilter := os.Getenv(*opts.FilterFromEnvVar)
+		parsedLvl := level.FromString(envFilter)
+		if parsedLvl != level.SeverityLevel(0) {
+			lvl = parsedLvl
+		}
+	}
 	if opts.FilterOnLevel != level.SeverityLevel(0) {
 		lvl = opts.FilterOnLevel
-	} else {
+	} else if lvl == level.SeverityLevel(0) {
 		lvl = level.TRACE + 1
 	}
 

pkg/level/level.go

@@ -1,6 +1,8 @@
 package level
 
 import (
+	"strings"
+
 	"git.ma-al.com/maal-libraries/observer/pkg/syslog"
 	"go.opentelemetry.io/otel/attribute"
 )
@@ -61,20 +63,21 @@ func (l SeverityLevel) String() string {
 }
 
 func FromString(level string) SeverityLevel {
+	level = strings.ToLower(level)
 	switch level {
-	case "ALERT":
+	case "alert":
 		return ALERT
-	case "CRIT":
+	case "crit", "critical":
 		return CRIT
-	case "ERR":
+	case "err", "error":
 		return ERR
-	case "WARN":
+	case "warn", "warning":
 		return WARN
-	case "INFO":
+	case "info":
 		return INFO
-	case "DEBUG":
+	case "debug":
 		return DEBUG
-	case "TRACE":
+	case "trace":
 		return TRACE
 	default:
 		return unset