Avoid modifications of base module host

Running the host parser in metricbeat modules modifies the host in the base module, so host parser cannot be run a second time. Change builders so they don't modify the host.
elastic · Jul 22, 2020 · 3605783 · 3605783
1 parent f543705
commit 3605783
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Showing 5 changed files with 5 additions and 23 deletions.
diff --git a/CHANGELOG-developer.next.asciidoc b/CHANGELOG-developer.next.asciidoc
@@ -97,3 +97,4 @@ The list below covers the major changes between 7.0.0-rc2 and master only.
 - Remove vendor folder from repository. {pull}18655[18655]
 - Added SQL helper that can be used from any Metricbeat module {pull}18955[18955]
 - Update Go version to 1.14.4. {pull}19753[19753]
+- Metricbeat module builders don't modify the base module host, so host parsers can be called multiple times with the original host. {pull}20143[20143]
diff --git a/metricbeat/mb/builders.go b/metricbeat/mb/builders.go
@@ -125,15 +125,14 @@ func initMetricSets(r *Register, m Module) ([]MetricSet, error) {
 		}
 
 		bm.registration = registration
-		bm.hostData = HostData{URI: bm.host}
+		bm.hostData = HostData{URI: bm.host, Host: bm.host}
 		if registration.HostParser != nil {
 			bm.hostData, err = registration.HostParser(bm.Module(), bm.host)
 			if err != nil {
 				errs = append(errs, errors.Wrapf(err, "host parsing failed for %v-%v",
 					bm.Module().Name(), bm.Name()))
 				continue
 			}
-			bm.host = bm.hostData.Host
 		}
 
 		metricSet, err := registration.Factory(bm)

diff --git a/metricbeat/mb/lightmetricset.go b/metricbeat/mb/lightmetricset.go
@@ -18,9 +18,6 @@
 package mb
 
 import (
-	"fmt"
-	"net/url"
-
 	"github.com/pkg/errors"
 
 	"github.com/elastic/beats/v7/libbeat/common"
@@ -86,12 +83,10 @@ func (m *LightMetricSet) Registration(r *Register) (MetricSetRegistration, error
 		// At this point host parser was already run, we need to run this again
 		// with the overriden defaults
 		if registration.HostParser != nil {
-			host := m.useHostURISchemeIfPossible(base.host, base.hostData.URI)
-			base.hostData, err = registration.HostParser(base.module, host)
+			base.hostData, err = registration.HostParser(base.module, base.host)
 			if err != nil {
 				return nil, errors.Wrapf(err, "host parser failed on light metricset factory for '%s/%s'", m.Module, m.Name)
 			}
-			base.host = base.hostData.Host
 		}
 
 		return originalFactory(base)
@@ -100,18 +95,6 @@ func (m *LightMetricSet) Registration(r *Register) (MetricSetRegistration, error
 	return registration, nil
 }
 
-// useHostURISchemeIfPossible method parses given URI to extract protocol scheme and prepend it to the host.
-// It prevents from skipping protocol scheme (e.g. https) while executing HostParser.
-func (m *LightMetricSet) useHostURISchemeIfPossible(host, uri string) string {
-	u, err := url.ParseRequestURI(uri)
-	if err == nil {
-		if u.Scheme != "" {
-			return fmt.Sprintf("%s://%s", u.Scheme, u.Host)
-		}
-	}
-	return host
-}
-
 // baseModule does the configuration overrides in the base module configuration
 // taking into account the light metric set default configurations
 func (m *LightMetricSet) baseModule(from Module) (*BaseModule, error) {

diff --git a/metricbeat/mb/mb.go b/metricbeat/mb/mb.go
@@ -283,7 +283,6 @@ type HostData struct {
 	SanitizedURI string // A sanitized version of the URI without credentials.
 
 	// Parts of the URI.
-
 	Host     string // The host and possibly port.
 	User     string // Username
 	Password string // Password
@@ -357,7 +356,7 @@ func (b *BaseMetricSet) Module() Module {
 // Host returns the hostname or other module specific value that identifies a
 // specific host or service instance from which to collect metrics.
 func (b *BaseMetricSet) Host() string {
-	return b.host
+	return b.hostData.Host
 }
 
 // HostData returns the parsed host data.

diff --git a/metricbeat/mb/mb_test.go b/metricbeat/mb/mb_test.go
@@ -236,7 +236,7 @@ func TestNewModulesHostParser(t *testing.T) {
 
 		// The URI is passed through in the Host() and HostData().URI.
 		assert.Equal(t, uri, ms.Host())
-		assert.Equal(t, HostData{URI: uri}, ms.HostData())
+		assert.Equal(t, HostData{URI: uri, Host: uri}, ms.HostData())
 	})
 
 	t.Run("MetricSet with HostParser", func(t *testing.T) {