Trim forward slashes from config urls (DataDog#4843)

* update branch for merge

* fix issue where unset site or dd_url parameters broke the run, update test to reflect

* add logic to check if domain is empty

* replace trimSuffix with cleaner trimRight function

* move trim slash function to be called after overrides, add method name to description

pkg/config/config.go

@@ -770,6 +770,7 @@ func load(config Config, origin string, loadSecret bool) error {
 	loadProxyFromEnv(config)
 	sanitizeAPIKey(config)
 	applyOverrides(config)
+	trimTrailingSlashFromURLS(config)
 	// setTracemallocEnabled *must* be called before setNumWorkers
 	setTracemallocEnabled(config)
 	setNumWorkers(config)
@@ -816,6 +817,48 @@ func sanitizeAPIKey(config Config) {
 	config.Set("api_key", strings.TrimSpace(config.GetString("api_key")))
 }
 
+//trimTrailingSlashFromURLS trims any forward slashes from the end of various config URL's (site, dd_url, and various additional endpoints)
+func trimTrailingSlashFromURLS(config Config) error {
+	var urls = []string{
+		"site",
+		"dd_url",
+	}
+	var additionalEndpointSelectors = []string{
+		"additional_endpoints",
+		"apm_config.additional_endpoints",
+		"logs_config.additional_endpoints",
+		"process_config.additional_endpoints",
+	}
+
+	for _, domain := range urls {
+		key := config.GetString(domain)
+		if key == "" {
+			continue
+		}
+		config.Set(domain, strings.TrimRight(key, "/"))
+	}
+
+	for _, es := range additionalEndpointSelectors {
+		additionalEndpoints := make(map[string][]string)
+		sanitizedAdditionalEndpoints := make(map[string][]string)
+
+		err := config.UnmarshalKey(es, &additionalEndpoints)
+
+		if err != nil {
+			return err
+		}
+		for domain, keys := range additionalEndpoints {
+			if domain == "" {
+				continue
+			}
+			domain = strings.TrimRight(domain, "/")
+			sanitizedAdditionalEndpoints[domain] = keys
+		}
+		config.Set(es, sanitizedAdditionalEndpoints)
+	}
+	return nil
+}
+
 // GetMainInfraEndpoint returns the main DD Infra URL defined in the config, based on the value of `site` and `dd_url`
 func GetMainInfraEndpoint() string {
 	return getMainInfraEndpointWithConfig(Datadog)

pkg/config/config_test.go

@@ -618,6 +618,72 @@ func TestSanitizeAPIKey(t *testing.T) {
 	assert.Equal(t, "foo", config.GetString("api_key"))
 }
 
+func TestTrimTrailingSlashFromURLS(t *testing.T) {
+	var urls = []string{
+		"site",
+		"dd_url",
+	}
+	var additionalEndpointSelectors = []string{
+		"additional_endpoints",
+		"apm_config.additional_endpoints",
+		"logs_config.additional_endpoints",
+		"process_config.additional_endpoints",
+	}
+	datadogYaml := `
+api_key: fakeapikey
+site: datadoghq.com/////
+dd_url:
+additional_endpoints:
+  testing.com///:
+  - fakekey
+  test2.com/:
+  - fakekey
+apm_config:
+  additional_endpoints:
+    testingapm.com//:
+    - fakekey
+    test2apm.com/:
+    - fakekey
+logs_config:
+  additional_endpoints:
+    testinglogs.com///////:
+    - fakekey
+    test2logs.com/:
+    - fakekey
+process_config:
+  additional_endpoints:
+    testingproc.com/////:
+    - fakekey
+    test2proc.com/:
+    - fakekey
+`
+	testConfig := setupConfFromYAML(datadogYaml)
+	trimTrailingSlashFromURLS(testConfig)
+
+	for _, u := range urls {
+		testString := testConfig.GetString(u)
+		if len(testString) == 0 {
+			continue
+		}
+		if testString[len(testString)-1:] == "/" {
+			t.Errorf("Error: The key %v: has a vlue of %v -- The trailing forward slash was not properly trimmed", u, testConfig.GetString(u))
+		}
+	}
+	for _, es := range additionalEndpointSelectors {
+		additionalEndpoints := make(map[string][]string)
+		err := testConfig.UnmarshalKey(es, &additionalEndpoints)
+		if err != nil {
+			t.Errorf("Error: %v", err)
+		}
+
+		for domain := range additionalEndpoints {
+			if domain[len(domain)-1:] == "/" {
+				t.Errorf("Error: The key %v: has a vlue of %v -- The trailing forward slash was not properly trimmed", es, domain)
+			}
+		}
+	}
+}
+
 // TestSecretBackendWithMultipleEndpoints tests an edge case of `viper.AllSettings()` when a config
 // key includes the key delimiter. Affects the config package when both secrets and multiple
 // endpoints are configured.