From 10e46be562e109dd0d15b717f0e0503fd107073c Mon Sep 17 00:00:00 2001
From: Augustin Husson <husson.augustin@gmail.com>
Date: Thu, 7 Nov 2024 17:05:17 +0100
Subject: [PATCH] add little filter capabilities (#19)

Signed-off-by: Augustin Husson <husson.augustin@gmail.com>
---
 README.md                 |  5 +++++
 go.mod                    |  1 +
 go.sum                    |  3 +++
 source/metric/endpoint.go | 32 +++++++++++++++++++++++++++++++-
 4 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index b16ea26..611792d 100644
--- a/README.md
+++ b/README.md
@@ -72,6 +72,11 @@ The tool provides an API endpoint, `/api/v1/metrics`, which returns the usage da
 }
 ```
 
+You can used the following query parameter to filter the list returned:
+
+* **metric_name**: when used, it will trigger a fuzzy search on the metric_name based on the pattern provided.
+* **used**: when used, will return only the metric used or not (depending if you set this boolean to true or to false). Leave it empty if you want both.
+
 ## How to use it
 
 ### Central instance
diff --git a/go.mod b/go.mod
index e799d49..2b622c4 100644
--- a/go.mod
+++ b/go.mod
@@ -6,6 +6,7 @@ require (
 	github.com/go-openapi/strfmt v0.23.0
 	github.com/grafana/grafana-openapi-client-go v0.0.0-20241101140420-bc381928ae6e
 	github.com/labstack/echo/v4 v4.12.0
+	github.com/lithammer/fuzzysearch v1.1.8
 	github.com/perses/common v0.26.0
 	github.com/perses/perses v0.49.0-rc.1.0.20241104091321-0a0482386006
 	github.com/prometheus/client_golang v1.20.5
diff --git a/go.sum b/go.sum
index eff655f..a2a3464 100644
--- a/go.sum
+++ b/go.sum
@@ -204,6 +204,8 @@ github.com/labstack/echo/v4 v4.12.0 h1:IKpw49IMryVB2p1a4dzwlhP1O2Tf2E0Ir/450lH+k
 github.com/labstack/echo/v4 v4.12.0/go.mod h1:UP9Cr2DJXbOK3Kr9ONYzNowSh7HP0aG0ShAyycHSJvM=
 github.com/labstack/gommon v0.4.2 h1:F8qTUNXgG1+6WQmqoUWnz8WiEU60mXVVw0P4ht1WRA0=
 github.com/labstack/gommon v0.4.2/go.mod h1:QlUFxVM+SNXhDL/Z7YhocGIBYOiwB0mXm1+1bAPHPyU=
+github.com/lithammer/fuzzysearch v1.1.8 h1:/HIuJnjHuXS8bKaiTMeeDlW2/AyIWk2brx1V8LFgLN4=
+github.com/lithammer/fuzzysearch v1.1.8/go.mod h1:IdqeyBClc3FFqSzYq/MXESsS4S0FsZ5ajtkr5xPLts4=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
@@ -392,6 +394,7 @@ golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/text v0.19.0 h1:kTxAhCbGbxhK0IwgSKiMO5awPoDQ0RpfiVYBfK860YM=
 golang.org/x/text v0.19.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
 golang.org/x/time v0.6.0 h1:eTDhh4ZXt5Qf0augr54TN6suAUudPcawVZeIAPU7D4U=
diff --git a/source/metric/endpoint.go b/source/metric/endpoint.go
index 0a50ed3..4975587 100644
--- a/source/metric/endpoint.go
+++ b/source/metric/endpoint.go
@@ -18,6 +18,7 @@ import (
 	"net/http"
 
 	"github.com/labstack/echo/v4"
+	"github.com/lithammer/fuzzysearch/fuzzy"
 	persesEcho "github.com/perses/common/echo"
 	"github.com/perses/metrics-usage/database"
 	v1 "github.com/perses/metrics-usage/pkg/api/v1"
@@ -49,8 +50,37 @@ func (e *endpoint) GetMetric(ctx echo.Context) error {
 	return ctx.JSON(http.StatusOK, metric)
 }
 
+type request struct {
+	MetricName string `query:"metric_name"`
+	Used       *bool  `query:"used"`
+}
+
+func (r *request) filter(list map[string]*v1.Metric) map[string]*v1.Metric {
+	result := make(map[string]*v1.Metric)
+	if len(r.MetricName) == 0 && r.Used == nil {
+		return list
+	}
+	for k, v := range list {
+		if len(r.MetricName) == 0 || fuzzy.Match(r.MetricName, k) {
+			if r.Used == nil {
+				result[k] = v
+			} else if *r.Used && list[k].Usage != nil {
+				result[k] = v
+			} else if !*r.Used && list[k].Usage == nil {
+				result[k] = v
+			}
+		}
+	}
+	return result
+}
+
 func (e *endpoint) ListMetrics(ctx echo.Context) error {
-	return ctx.JSON(http.StatusOK, e.db.ListMetrics())
+	req := &request{}
+	err := ctx.Bind(req)
+	if err != nil {
+		return ctx.JSON(http.StatusBadRequest, echo.Map{"message": err.Error()})
+	}
+	return ctx.JSON(http.StatusOK, req.filter(e.db.ListMetrics()))
 }
 
 func (e *endpoint) PushMetricsUsage(ctx echo.Context) error {