From 7e90814fde935ea528fbd125b5e44ce101293f87 Mon Sep 17 00:00:00 2001
From: "Stanislav N. aka pztrn" <pztrn@pztrn.name>
Date: Wed, 23 Dec 2020 13:37:52 +0500
Subject: [PATCH] Return list of parsed metrics, for autodiscovery.

---
 internal/application/api_responder.go | 21 +++++++++++++++++++--
 internal/models/metric.go             | 18 +++++++++---------
 internal/storage/generic.go           |  2 ++
 internal/storage/memory/memory.go     | 11 +++++++++++
 4 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/internal/application/api_responder.go b/internal/application/api_responder.go
index 8dc851a..a2301af 100644
--- a/internal/application/api_responder.go
+++ b/internal/application/api_responder.go
@@ -1,16 +1,33 @@
 package application
 
 import (
+	"encoding/json"
+
 	"go.dev.pztrn.name/metricator/internal/models"
 )
 
 // Responds with needed data. First parameter is a type of data needed (like metric name),
 // second parameter is actual metric name. Second parameter also can be empty.
 func (a *Application) respond(rInfo *models.RequestInfo) string {
-	metric, err := a.storage.Get(rInfo.Metric)
+	// If metric was requested - return only it.
+	if rInfo.Metric != "" {
+		metric, err := a.storage.Get(rInfo.Metric)
+		if err != nil {
+			return ""
+		}
+
+		return metric.GetValue()
+	}
+
+	// Otherwise we should get all metrics as slice and return them as string.
+	// This is needed for metrics autodiscovery.
+	metrics := a.storage.GetAsSlice()
+
+	metricsBytes, err := json.Marshal(metrics)
 	if err != nil {
+		// ToDo: log error
 		return ""
 	}
 
-	return metric.GetValue()
+	return string(metricsBytes)
 }
diff --git a/internal/models/metric.go b/internal/models/metric.go
index dca7cf9..6a08988 100644
--- a/internal/models/metric.go
+++ b/internal/models/metric.go
@@ -3,21 +3,21 @@ package models
 // Metric is a generic metric structure.
 type Metric struct {
 	// Metric name.
-	name string
+	Name string
 	// HELP data, if present.
-	description string
+	Description string
 	// Additional parameters, data inside "{}".
-	params []string
+	Params []string
 	// Metric value.
-	value string
+	Value string
 }
 
 // NewMetric creates new structure for storing single metric data.
 func NewMetric(name, description string, params []string) Metric {
 	m := Metric{
-		name:        name,
-		description: description,
-		params:      params,
+		Name:        name,
+		Description: description,
+		Params:      params,
 	}
 
 	return m
@@ -25,10 +25,10 @@ func NewMetric(name, description string, params []string) Metric {
 
 // GetValue returns metric's value.
 func (m *Metric) GetValue() string {
-	return m.value
+	return m.Value
 }
 
 // SetValue sets value for metric.
 func (m *Metric) SetValue(value string) {
-	m.value = value
+	m.Value = value
 }
diff --git a/internal/storage/generic.go b/internal/storage/generic.go
index 6326937..ef84278 100644
--- a/internal/storage/generic.go
+++ b/internal/storage/generic.go
@@ -7,6 +7,8 @@ import "go.dev.pztrn.name/metricator/internal/models"
 type GenericStorage interface {
 	// Get returns data from storage by key.
 	Get(string) (models.Metric, error)
+	// GetAsSlice returns all data from storage as slice.
+	GetAsSlice() []models.Metric
 	// GetDoneChan returns a channel which should be used to block execution
 	// until storage's routines are completed.
 	GetDoneChan() chan struct{}
diff --git a/internal/storage/memory/memory.go b/internal/storage/memory/memory.go
index 215aebc..ce2ce57 100644
--- a/internal/storage/memory/memory.go
+++ b/internal/storage/memory/memory.go
@@ -46,6 +46,17 @@ func (s *Storage) Get(key string) (models.Metric, error) {
 	return data, nil
 }
 
+// GetAsSlice returns all data from storage as slice.
+func (s *Storage) GetAsSlice() []models.Metric {
+	metrics := make([]models.Metric, 0, len(s.data))
+
+	for _, metric := range s.data {
+		metrics = append(metrics, metric)
+	}
+
+	return metrics
+}
+
 // GetDoneChan returns a channel which should be used to block execution
 // until storage's routines are completed.
 func (s *Storage) GetDoneChan() chan struct{} {