Expose the Prometheus exporter port when specified in the config

.chloggen/1689-expose-prometheusexporter-pod-when-enabled.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. operator, target allocator, github action)
+component: operator
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Expose the Prometheus exporter port in the OpenTelemetry Collector container when it is used in the configuration.
+
+# One or more tracking issues related to the change
+issues: [1689]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:

pkg/collector/container.go

@@ -16,7 +16,10 @@ package collector
 
 import (
 	"fmt"
+	"net"
 	"sort"
+	"strconv"
+	"strings"
 
 	"github.com/go-logr/logr"
 	corev1 "k8s.io/api/core/v1"
@@ -183,9 +186,65 @@ func getConfigContainerPorts(logger logr.Logger, cfg string) map[string]corev1.C
 		ContainerPort: metricsPort,
 		Protocol:      corev1.ProtocolTCP,
 	}
+
+	promExporterPorts, errs := getPrometheusExporterPorts(c)
+	for _, err := range errs {
+		logger.V(2).Info("There was a problem getting the prometheus exporter port: %s", err)
+	}
+	for _, promPort := range promExporterPorts {
+		ports[promPort.Name] = promPort
+	}
+
 	return ports
 }
 
+func getPrometheusExporterPort(exporterConfig map[interface{}]interface{}) (int32, error) {
+	var promPort int32 = 0
+	if endpoint, ok := exporterConfig["endpoint"]; ok {
+		_, port, err := net.SplitHostPort(endpoint.(string))
+		if err != nil {
+			return 0, err
+		}
+		i64, err := strconv.ParseInt(port, 10, 32)
+		if err != nil {
+			return 0, err
+		}
+		promPort = int32(i64)
+	}
+	return promPort, nil
+}
+
+func getPrometheusExporterPorts(c map[interface{}]interface{}) ([]corev1.ContainerPort, []error) {
+	errors := make([]error, 0)
+	ports := make([]corev1.ContainerPort, 0)
+	if exporters, ok := c["exporters"]; ok && exporters != nil {
+		for e, exporterConfig := range exporters.(map[interface{}]interface{}) {
+			exporterName := e.(string)
+			if strings.Contains(exporterName, "prometheus") {
+				containerPort, err := getPrometheusExporterPort(exporterConfig.(map[interface{}]interface{}))
+				if err != nil {
+					errors = append(errors,
+						fmt.Errorf(
+							"there was a problem getting the port. Exporter %s",
+							exporterName,
+						),
+					)
+				}
+				ports = append(ports,
+					corev1.ContainerPort{
+						Name:          naming.PortName(exporterName),
+						ContainerPort: containerPort,
+						Protocol:      corev1.ProtocolTCP,
+					},
+				)
+			}
+		}
+	} else {
+		errors = append(errors, fmt.Errorf("no exporters specified in the configuration"))
+	}
+	return ports, errors
+}
+
 func portMapToList(portMap map[string]corev1.ContainerPort) []corev1.ContainerPort {
 	ports := make([]corev1.ContainerPort, 0, len(portMap))
 	for _, p := range portMap {

pkg/collector/container_test.go

@@ -177,6 +177,43 @@ service:
 				},
 			},
 		},
+		{
+			description: "prometheus exporter",
+			specConfig: `exporters:
+    prometheus:
+        endpoint: "0.0.0.0:9090"`,
+			specPorts: []corev1.ServicePort{},
+			expectedPorts: []corev1.ContainerPort{
+				metricContainerPort,
+				{
+					Name:          "prometheus",
+					ContainerPort: 9090,
+					Protocol:      corev1.ProtocolTCP,
+				},
+			},
+		},
+		{
+			description: "multiple prometheus exporters",
+			specConfig: `exporters:
+    prometheus/prod:
+        endpoint: "0.0.0.0:9090"
+    prometheus/dev:
+        endpoint: "0.0.0.0:9091"`,
+			specPorts: []corev1.ServicePort{},
+			expectedPorts: []corev1.ContainerPort{
+				metricContainerPort,
+				{
+					Name:          "prometheus-prod",
+					ContainerPort: 9090,
+					Protocol:      corev1.ProtocolTCP,
+				},
+				{
+					Name:          "prometheus-dev",
+					ContainerPort: 9091,
+					Protocol:      corev1.ProtocolTCP,
+				},
+			},
+		},
 	}
 
 	for _, testCase := range tests {

pkg/naming/ports.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package naming
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+// PortName returns a dns-safe string for the given name.
+// Any char that is not [a-z0-9] is replaced by "-" or "a".
+// Replacement character "a" is used only at the beginning or at the end of the name.
+// The function does not change length of the string.
+func PortName(name string) string {
+	var d []rune
+
+	for i, x := range strings.ToLower(name) {
+		if regex.Match([]byte(string(x))) {
+			d = append(d, x)
+		} else if i == 0 || i == utf8.RuneCountInString(name)-1 {
+			d = append(d, 'a')
+		} else {
+			d = append(d, '-')
+		}
+	}
+
+	return string(d)
+}

pkg/naming/ports_test.go

@@ -0,0 +1,43 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package naming
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPortName(t *testing.T) {
+	var tests = []struct {
+		in  string
+		out string
+	}{
+		{"simplest", "simplest"},
+		{"prometheus/dev", "prometheus-dev"},
+		{"prometheus.dev", "prometheus-dev"},
+		{"prometheus-", "prometheusa"},
+		{"-prometheus", "aprometheus"},
+	}
+	rule, err := regexp.Compile(`^[a-z0-9]([-a-z0-9]*[a-z0-9])?$`)
+	assert.NoError(t, err)
+
+	for _, tt := range tests {
+		assert.Equal(t, tt.out, PortName(tt.in))
+		matched := rule.Match([]byte(tt.out))
+		assert.True(t, matched, "%v is not a valid name", tt.out)
+	}
+}