cmd: accept URL as a configuration file

cmd/config.go

@@ -1,9 +1,12 @@
 package cmd
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"io/ioutil"
+	"net/http"
+	"net/url"
 	"os"
 	"strconv"
 	"strings"
@@ -27,12 +30,37 @@ type ConfigRelatedOptions struct {
 func (c ConfigRelatedOptions) Parse(out io.Writer, component string, config interface{}) error {
 	var rawConfig map[string]interface{}
 	if cfgFile := c.Path; cfgFile != "" {
-		input, err := ioutil.ReadFile(cfgFile)
+		if strings.HasPrefix(cfgFile, "http://") || strings.HasPrefix(cfgFile, "https://") {
-		if err != nil {
+			u, err := url.Parse(cfgFile)
-			return fmt.Errorf("unable to read configuration file: %w", err)
+			if err != nil {
-		}
+				return fmt.Errorf("cannot parse configuration URL: %w", err)
-		if err := yaml.Unmarshal(input, &rawConfig); err != nil {
+			}
-			return fmt.Errorf("unable to parse configuration file: %w", err)
+			if u.Path == "" {
+				u.Path = fmt.Sprintf("/api/v0/orchestrator/configuration/%s", component)
+			}
+			resp, err := http.Get(u.String())
+			if err != nil {
+				return fmt.Errorf("unable to fetch configuration file: %w", err)
+			}
+			defer resp.Body.Close()
+			if contentType := resp.Header.Get("Content-Type"); contentType != "application/json" {
+				return fmt.Errorf("received configuration file is not JSON (%s)", contentType)
+			}
+			input, err := io.ReadAll(resp.Body)
+			if err != nil {
+				return fmt.Errorf("unable to read configuration file: %w", err)
+			}
+			if err := json.Unmarshal(input, &rawConfig); err != nil {
+				return fmt.Errorf("unable to parse JSON configuration file: %w", err)
+			}
+		} else {
+			input, err := ioutil.ReadFile(cfgFile)
+			if err != nil {
+				return fmt.Errorf("unable to read configuration file: %w", err)
+			}
+			if err := yaml.Unmarshal(input, &rawConfig); err != nil {
+				return fmt.Errorf("unable to parse configuration file: %w", err)
+			}
 		}
 	}
 

cmd/config_test.go

@@ -2,9 +2,13 @@ package cmd_test
 
 import (
 	"bytes"
+	"fmt"
 	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
@@ -40,21 +44,23 @@ type dummyModule2DetailsConfiguration struct {
 	IntervalValue time.Duration
 }
 
-var dummyDefaultConfiguration = dummyConfiguration{
+func dummyDefaultConfiguration() dummyConfiguration {
-	Module1: dummyModule1Configuration{
+	return dummyConfiguration{
-		Listen:  "127.0.0.1:8080",
+		Module1: dummyModule1Configuration{
-		Topic:   "nothingness",
+			Listen:  "127.0.0.1:8080",
-		Workers: 100,
+			Topic:   "nothingness",
-	},
+			Workers: 100,
-	Module2: dummyModule2Configuration{
-		MoreDetails: MoreDetails{
-			Stuff: "hello",
 		},
-		Details: dummyModule2DetailsConfiguration{
+		Module2: dummyModule2Configuration{
-			Workers:       1,
+			MoreDetails: MoreDetails{
-			IntervalValue: time.Minute,
+				Stuff: "hello",
+			},
+			Details: dummyModule2DetailsConfiguration{
+				Workers:       1,
+				IntervalValue: time.Minute,
+			},
 		},
-	},
+	}
 }
 
 func TestDump(t *testing.T) {
@@ -80,7 +86,7 @@ module2:
 		Dump: true,
 	}
 
-	parsed := dummyDefaultConfiguration
+	parsed := dummyDefaultConfiguration()
 	out := bytes.NewBuffer([]byte{})
 	if err := c.Parse(out, "dummy", &parsed); err != nil {
 		t.Fatalf("Parse() error:\n%+v", err)
@@ -157,6 +163,15 @@ module2:
 	ioutil.WriteFile(configFile, []byte(config), 0644)
 
 	// Environment
+	clean := func() {
+		for _, env := range os.Environ() {
+			if strings.HasPrefix(env, "AKVORADO_DUMMY_") {
+				os.Unsetenv(strings.Split(env, "=")[0])
+			}
+		}
+	}
+	clean()
+	defer clean()
 	os.Setenv("AKVORADO_DUMMY_MODULE1_LISTEN", "127.0.0.1:9000")
 	os.Setenv("AKVORADO_DUMMY_MODULE1_TOPIC", "something")
 	os.Setenv("AKVORADO_DUMMY_MODULE2_DETAILS_INTERVALVALUE", "10m")
@@ -171,7 +186,7 @@ module2:
 		Dump: true,
 	}
 
-	parsed := dummyDefaultConfiguration
+	parsed := dummyDefaultConfiguration()
 	out := bytes.NewBuffer([]byte{})
 	if err := c.Parse(out, "dummy", &parsed); err != nil {
 		t.Fatalf("Parse() error:\n%+v", err)
@@ -201,3 +216,63 @@ module2:
 		t.Errorf("Parse() (-got, +want):\n%s", diff)
 	}
 }
+
+func TestHTTPConfiguration(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		fmt.Fprint(w, `
+{
+ "module1": {
+  "topic": "flows"
+ },
+ "module2": {
+  "details": {
+   "workers": 5,
+   "interval-value": "20m"
+  },
+  "stuff": "bye",
+  "elements": [
+   {"name": "first", "gauge": 67},
+   {"name": "second"}
+  ]
+ }
+}
+`)
+	}))
+	defer ts.Close()
+
+	c := cmd.ConfigRelatedOptions{
+		Path: ts.URL,
+		Dump: true,
+	}
+
+	parsed := dummyDefaultConfiguration()
+	out := bytes.NewBuffer([]byte{})
+	if err := c.Parse(out, "dummy", &parsed); err != nil {
+		t.Fatalf("Parse() error:\n%+v", err)
+	}
+	// Expected configuration
+	expected := dummyConfiguration{
+		Module1: dummyModule1Configuration{
+			Listen:  "127.0.0.1:8080",
+			Topic:   "flows",
+			Workers: 100,
+		},
+		Module2: dummyModule2Configuration{
+			MoreDetails: MoreDetails{
+				Stuff: "bye",
+			},
+			Details: dummyModule2DetailsConfiguration{
+				Workers:       5,
+				IntervalValue: 20 * time.Minute,
+			},
+			Elements: []dummyModule2ElementsConfiguration{
+				{"first", 67},
+				{"second", 0},
+			},
+		},
+	}
+	if diff := helpers.Diff(parsed, expected); diff != "" {
+		t.Errorf("Parse() (-got, +want):\n%s", diff)
+	}
+}