add promyaml kata

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/google/go-cmp v0.5.9
 	github.com/rogpeppe/go-internal v1.11.0
 	golang.org/x/net v0.13.0
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (

go.sum

@@ -8,3 +8,7 @@ golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/tools v0.1.12 h1:VveCTK38A2rkS8ZqFY25HIDFscX5X9OoEhJd3quQmXU=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

katas.md

@@ -1,3 +1,4 @@
+* 2023-09-19: promyaml
 * 2023-09-18: kv
 * 2023-09-13: battery
 * 2023-09-11: older

promyaml/promyaml.go

@@ -0,0 +1,40 @@
+// Package promyaml shows how to get (Prometheus) configuration from YAML file.
+//
+// Level: intermediate
+// Topics: yaml, tpg-tools
+package promyaml
+
+import (
+	"os"
+	"time"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Global GlobalConfig
+}
+
+type GlobalConfig struct {
+	ScrapeInterval     time.Duration     `yaml:"scrape_interval"`
+	EvaluationInterval time.Duration     `yaml:"evaluation_interval"`
+	ScrapeTimeout      time.Duration     `yaml:"scrape_timeout"`
+	ExternalLabels     map[string]string `yaml:"external_labels"`
+}
+
+func ConfigFrom(path string) (Config, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return Config{}, err
+	}
+	defer f.Close()
+	config := Config{
+		GlobalConfig{
+			ScrapeTimeout: 10 * time.Second, // default
+		},
+	}
+	if err := yaml.NewDecoder(f).Decode(&config); err != nil {
+		return Config{}, err
+	}
+	return config, err
+}

promyaml/promyaml_test.go

@@ -0,0 +1,32 @@
+package promyaml_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/jreisinger/gokatas/promyaml"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func TestConfigFrom_CorrectlyParsesYAMLData(t *testing.T) {
+	t.Parallel()
+	want := promyaml.Config{
+		Global: promyaml.GlobalConfig{
+			ScrapeInterval:     15 * time.Second,
+			EvaluationInterval: 30 * time.Second,
+			ScrapeTimeout:      10 * time.Second,
+			ExternalLabels: map[string]string{
+				"monitor": "codelab",
+				"foo":     "bar",
+			},
+		},
+	}
+	got, err := promyaml.ConfigFrom("testdata/prom.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !cmp.Equal(want, got) {
+		t.Error(cmp.Diff(want, got))
+	}
+}

promyaml/testdata/prom.yaml

@@ -0,0 +1,9 @@
+# my global config
+global:
+  scrape_interval: 15s
+  evaluation_interval: 30s
+  # scrape_timeout is set to the global default (10s).
+
+  external_labels:
+    monitor: codelab
+    foo: bar