From 2e91886056422e73859f4632fe1523f198898048 Mon Sep 17 00:00:00 2001
From: Kamil Samigullin <kamil@samigullin.info>
Date: Thu, 25 Jun 2020 23:28:04 +0300
Subject: [PATCH] issue #28: simplify filter.Filter

---
 internal/cmd/coverage.go   |  4 ++--
 internal/cmd/metrics.go    |  4 ++--
 internal/cnf/config.go     | 10 ++++++++++
 internal/filter/metric.go  |  8 +-------
 internal/repl/decorator.go | 13 +++++++++++++
 internal/repl/executor.go  |  6 ++----
 6 files changed, 30 insertions(+), 15 deletions(-)
 create mode 100644 internal/repl/decorator.go

diff --git a/internal/cmd/coverage.go b/internal/cmd/coverage.go
index 3037b78..6a378d9 100644
--- a/internal/cmd/coverage.go
+++ b/internal/cmd/coverage.go
@@ -135,7 +135,7 @@ func NewCoverageCommand(
 
 			printer.SetPrefix(config.Graphite.Prefix)
 			if !replMode {
-				metrics, err := filter.Filter(metrics, config.Graphite.Filter, config.Graphite.Prefix)
+				metrics, err := filter.Filter(metrics, config.Pattern())
 				if err != nil {
 					return err
 				}
@@ -144,7 +144,7 @@ func NewCoverageCommand(
 				return printer.PrintCoverage(reporter.Report(metrics))
 			}
 			prompt.New(
-				repl.NewCoverageExecutor(config.Graphite.Prefix, metrics, reporter, printer, logger),
+				repl.Prefix(config.Graphite.Prefix, repl.NewCoverageExecutor(metrics, reporter, printer, logger)),
 				repl.NewMetricsCompleter(metrics),
 			).Run()
 			return nil
diff --git a/internal/cmd/metrics.go b/internal/cmd/metrics.go
index 8e89b10..a9d5dd1 100644
--- a/internal/cmd/metrics.go
+++ b/internal/cmd/metrics.go
@@ -83,7 +83,7 @@ func NewMetricsCommand(
 
 			printer.SetPrefix(config.Graphite.Prefix)
 			if !replMode {
-				metrics, err = filter.Filter(metrics, config.Graphite.Filter, config.Graphite.Prefix)
+				metrics, err = filter.Filter(metrics, config.Pattern())
 				if err != nil {
 					return err
 				}
@@ -92,7 +92,7 @@ func NewMetricsCommand(
 				return printer.PrintMetrics(metrics)
 			}
 			prompt.New(
-				repl.NewMetricsExecutor(config.Graphite.Prefix, metrics, printer, logger),
+				repl.Prefix(config.Graphite.Prefix, repl.NewMetricsExecutor(metrics, printer, logger)),
 				repl.NewMetricsCompleter(metrics),
 			).Run()
 			return nil
diff --git a/internal/cnf/config.go b/internal/cnf/config.go
index 34fb693..7ef14bd 100644
--- a/internal/cnf/config.go
+++ b/internal/cnf/config.go
@@ -1,5 +1,7 @@
 package cnf
 
+import "strings"
+
 // Config contains all necessary tool configuration.
 type Config struct {
 	Grafana struct {
@@ -12,3 +14,11 @@ type Config struct {
 		Prefix string `mapstructure:"metrics"`
 	} `mapstructure:",squash"`
 }
+
+func (config Config) Pattern() string {
+	pattern, prefix := config.Graphite.Filter, config.Graphite.Prefix
+	if !strings.HasPrefix(pattern, prefix) {
+		pattern = prefix + "." + pattern
+	}
+	return pattern
+}
diff --git a/internal/filter/metric.go b/internal/filter/metric.go
index 6015edd..ad8b01d 100644
--- a/internal/filter/metric.go
+++ b/internal/filter/metric.go
@@ -1,8 +1,6 @@
 package filter
 
 import (
-	"strings"
-
 	"github.com/gobwas/glob"
 	"github.com/pkg/errors"
 
@@ -28,15 +26,11 @@ func Exclude(metrics provider.Metrics, pattern string) (provider.Metrics, error)
 	return filtered, nil
 }
 
-func Filter(metrics provider.Metrics, pattern, prefix string) (provider.Metrics, error) {
+func Filter(metrics provider.Metrics, pattern string) (provider.Metrics, error) {
 	if len(metrics) == 0 || pattern == "" {
 		return metrics, nil
 	}
 
-	if !strings.HasPrefix(pattern, prefix) {
-		pattern = prefix + "." + pattern
-	}
-
 	matcher, err := glob.Compile(pattern)
 	if err != nil {
 		return metrics, errors.Wrapf(err, "filter: compile pattern %q", pattern)
diff --git a/internal/repl/decorator.go b/internal/repl/decorator.go
new file mode 100644
index 0000000..7e58d8f
--- /dev/null
+++ b/internal/repl/decorator.go
@@ -0,0 +1,13 @@
+package repl
+
+import "strings"
+
+func Prefix(prefix string, fn func(string)) func(string) {
+	return func(pattern string) {
+		pattern = strings.TrimSpace(pattern)
+		if pattern != "" {
+			pattern = prefix + "." + pattern
+		}
+		fn(pattern)
+	}
+}
diff --git a/internal/repl/executor.go b/internal/repl/executor.go
index aea6014..018fae4 100644
--- a/internal/repl/executor.go
+++ b/internal/repl/executor.go
@@ -11,7 +11,6 @@ import (
 )
 
 func NewCoverageExecutor(
-	prefix string,
 	metrics provider.Metrics,
 	reporter interface {
 		Report(provider.Metrics) model.Report
@@ -20,7 +19,7 @@ func NewCoverageExecutor(
 	logger *logrus.Logger,
 ) func(string) {
 	return func(pattern string) {
-		metrics, err := filter.Filter(metrics, pattern, prefix)
+		metrics, err := filter.Filter(metrics, pattern)
 		if err != nil {
 			logger.WithError(err).WithField("pattern", pattern).Error("repl: filter metrics")
 			return
@@ -35,13 +34,12 @@ func NewCoverageExecutor(
 }
 
 func NewMetricsExecutor(
-	prefix string,
 	metrics provider.Metrics,
 	printer interface{ PrintMetrics(provider.Metrics) error },
 	logger *logrus.Logger,
 ) func(string) {
 	return func(pattern string) {
-		metrics, err := filter.Filter(metrics, pattern, prefix)
+		metrics, err := filter.Filter(metrics, pattern)
 		if err != nil {
 			logger.WithError(err).WithField("pattern", pattern).Error("repl: filter metrics")
 			return