Cloud Foundry metrics receiver #1 - config, factory, docs (#4626)

Adds a Cloud Foundry metric receiver which reads metrics from Cloud Foundry Reverse Log Proxy Gateway. More details available in the `README.md`. `make gotidy` seems to have made plenty of subtle changes to `go.sum` files, not sure if this is normal. This PR contains the overall structure, documentation, implementation for config and factory, but does NOT contain the implementation of the receiver and does not enable the component, as that will come in separate PRs later.

**Link to tracking Issue:** #5320

**Testing:** Unit tests. Manual testing was performed against Tanzu Application Service (TAS) versions 2.7, 2.8 and 2.11. Considered adding an integration test with mocked HTTP servers acting as endpoints where the HTTP server would provide a constant response (prerecorded from the real TAS traffic), but not sure if mocks would make more sense.

**Documentation:** `README.md` and `doc.go` for the new receiver module were added.

.github/CODEOWNERS

@@ -69,6 +69,7 @@ receiver/awscontainerinsightreceiver/                @open-telemetry/collector-c
 receiver/awsecscontainermetricsreceiver/             @open-telemetry/collector-contrib-approvers @kbrockhoff @anuraaga
 receiver/awsxrayreceiver/                            @open-telemetry/collector-contrib-approvers @kbrockhoff @anuraaga
 receiver/carbonreceiver/                             @open-telemetry/collector-contrib-approvers @pjanotti
+receiver/cloudfoundryreceiver/                       @open-telemetry/collector-contrib-approvers @agoallikmaa @pellared
 receiver/collectdreceiver/                           @open-telemetry/collector-contrib-approvers @owais
 receiver/dockerstatsreceiver/                        @open-telemetry/collector-contrib-approvers @rmfitzpatrick
 receiver/dotnetdiagnosticsreceiver/                  @open-telemetry/collector-contrib-approvers @pmcollins @davmason

.github/dependabot.yml

@@ -401,6 +401,10 @@ updates:
     directory: "/receiver/carbonreceiver"
     schedule:
       interval: "weekly"
+  - package-ecosystem: "gomod"
+    directory: "/receiver/cloudfoundryreceiver"
+    schedule:
+      interval: "weekly"
   - package-ecosystem: "gomod"
     directory: "/receiver/collectdreceiver"
     schedule:

go.mod

@@ -559,6 +559,8 @@ replace github.com/open-telemetry/opentelemetry-collector-contrib/receiver/awsxr
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/receiver/carbonreceiver => ./receiver/carbonreceiver
 
+replace github.com/open-telemetry/opentelemetry-collector-contrib/receiver/cloudfoundryreceiver => ./receiver/cloudfoundryreceiver
+
 replace github.com/open-telemetry/opentelemetry-collector-contrib/receiver/collectdreceiver => ./receiver/collectdreceiver
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/receiver/dotnetdiagnosticsreceiver => ./receiver/dotnetdiagnosticsreceiver

receiver/cloudfoundryreceiver/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

receiver/cloudfoundryreceiver/README.md

@@ -0,0 +1,90 @@
+# Cloud Foundry Receiver
+
+The Cloud Foundry receiver connects to the RLP (Reverse Log Proxy) Gateway of the Cloud Foundry installation, typically
+available at the URL `https://log-stream.<cf-system-domain>`.
+
+## Authentication
+
+RLP Gateway authentication is performed by adding the Oauth2 token as the `Authorization` header. To obtain an OAuth2
+token to use for the RLP Gateway, a request is made to the UAA component which acts as the OAuth2 provider (URL
+specified by `uaa_url` configuration option, which typically is `https://uaa.<cf-system-domain>`). To authenticate with
+UAA, username and password/secret combination is used (`uaa_username` and `uaa_password` configuration options). This
+UAA user must have the `client_credentials` and `refresh_token` authorized grant types, and `logs.admin` authority.
+
+The following is an example sequence of commands to create the UAA user using the `uaac` command line utility:
+
+* `uaac target https://uaa.<cf-system-domain>`
+* `uaac token client get identity -s <identity-user-secret>`
+* `uaac client add <uaa_username> --name opentelemetry --secret <uaa_password> --authorized_grant_types client_credentials,refresh_token --authorities logs.admin`
+
+The `<uaa_username>` and `<uaa_password>` above can be set to anything as long as they match the values provided to the
+receiver configuration. The admin account (which is `identity` here) which has the permissions to create new clients may
+have a different name on different setups. The value of `--name` is not used for receiver configuration.
+
+## Configuration
+
+The receiver takes the following configuration options:
+
+| Field | Default | Description |
+| --- | --- | --- |
+| `rlp_gateway_url` | required | URL of the RLP gateway, typically `https://log-stream.<cf-system-domain>` |
+| `rlp_gateway_skip_tls_verify` | `false` | whether to skip TLS verify for the RLP Gateway endpoint |
+| `rlp_gateway_shard_id` | `opentelemetry` | metrics are load balanced among receivers that use the same shard ID, therefore this must only be set if there are multiple receivers which must both receive all the metrics instead of them being balanced between them |
+| `uaa_url` | required | URL of the UAA provider, typically `https://uaa.<cf-system-domain>` |
+| `uaa_skip_tls_verify` | `false` | whether to skip TLS verify for the UAA endpoint |
+| `uaa_username` | required | name of the UAA user (required grant types/authorities described above) |
+| `uaa_password` | required | password of the UAA user |
+| `http_timeout` | `10s` | HTTP socket timeout used for RLP Gateway |
+
+Example:
+
+```yaml
+receivers:
+  cloudfoundry:
+    rlp_gateway_url: "https://log-stream.sys.example.internal"
+    rlp_gateway_skip_tls_verify: false
+    rlp_gateway_shard_id: "opentelemetry"
+    uaa_url: "https://uaa.sys.example.internal"
+    uaa_skip_tls_verify: false
+    uaa_username: "otelclient"
+    uaa_password: "changeit"
+    http_timeout: "20s"
+```
+
+The full list of settings exposed for this receiver are documented [here](./config.go)
+with detailed sample configurations [here](./testdata/config.yaml).
+
+## Metrics
+
+Reported metrics are grouped under an instrumentation library named `otelcol/cloudfoundry`. Metric names are as
+specified by [Cloud Foundry metrics documentation](https://docs.cloudfoundry.org/running/all_metrics.html), but the
+origin name is prepended to the metric name with `.` separator. All metrics either of type `Gauge` or `Sum`.
+
+### Attributes
+
+All the metrics have the following attributes:
+* `origin` - origin name as documented by Cloud Foundry
+* `source` - for applications, the GUID of the application, otherwise equal to `origin`
+
+For CF/TAS deployed in BOSH, the following attributes are also present, using their canonical BOSH meanings:
+* `deployment` - BOSH deployment name
+* `index` - BOSH instance ID (GUID)
+* `ip` - BOSH instance IP
+* `job` - BOSH job name
+
+For metrics originating with `rep` origin name (specific to applications), the following metrics are present:
+* `instance_id` - numerical index of the application instance. However, also present for `bbs` origin, where it matches
+  the value of `index`
+* `process_id` - process ID (GUID). For a process of type "web" which is the main process of an application, this is
+  equal to `source_id` and `app_id`
+* `process_instance_id` - unique ID of a process instance, should be treated as an opaque string
+* `process_type` - process type. Each application has exactly one process of type `web`, but many have any number of
+  other processes
+
+On TAS/PCF versions 2.8.0+ and cf-deployment versions v11.1.0+, the following additional attributes are present for
+application metrics: `app_id`, `app_name`, `space_id`, `space_name`, `organization_id`, `organization_name` which
+provide the GUID and name of application, space and organization respectively.
+
+This might not be a comprehensive list of attributes, as the receiver passes on whatever attributes the gateway
+provides, which may include some that are specific to TAS and possibly new ones in future Cloud Foundry versions as
+well.

receiver/cloudfoundryreceiver/config.go

@@ -0,0 +1,68 @@
+// Copyright 2019, 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 cloudfoundryreceiver
+
+import (
+	"fmt"
+	"net/url"
+	"time"
+
+	"go.opentelemetry.io/collector/config"
+)
+
+// Config defines configuration for Collectd receiver.
+type Config struct {
+	config.ReceiverSettings `mapstructure:",squash"`
+
+	RLPGatewayURL           string        `mapstructure:"rlp_gateway_url"`
+	RLPGatewaySkipTLSVerify bool          `mapstructure:"rlp_gateway_skip_tls_verify"`
+	RLPGatewayShardID       string        `mapstructure:"rlp_gateway_shard_id"`
+	UAAUrl                  string        `mapstructure:"uaa_url"`
+	UAASkipTLSVerify        bool          `mapstructure:"uaa_skip_tls_verify"`
+	UAAUsername             string        `mapstructure:"uaa_username"`
+	UAAPassword             string        `mapstructure:"uaa_password"`
+	HTTPTimeout             time.Duration `mapstructure:"http_timeout"`
+}
+
+func (c *Config) Validate() error {
+	err := validateURLOption("rlp_gateway_url", c.RLPGatewayURL)
+	if err != nil {
+		return err
+	}
+
+	err = validateURLOption("uaa_url", c.UAAUrl)
+	if err != nil {
+		return err
+	}
+
+	if c.UAAUsername == "" {
+		return fmt.Errorf("username not specified")
+	}
+
+	return nil
+}
+
+func validateURLOption(name string, value string) error {
+	if value == "" {
+		return fmt.Errorf("%s not specified", name)
+	}
+
+	_, err := url.Parse(value)
+	if err != nil {
+		return fmt.Errorf("failed to parse %s as url: %v", name, err)
+	}
+
+	return nil
+}

receiver/cloudfoundryreceiver/config_test.go

@@ -0,0 +1,59 @@
+// Copyright 2019, 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 cloudfoundryreceiver
+
+import (
+	"path"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/config/configtest"
+)
+
+// todo implement - implement negative tests in stage 2 PR
+func TestLoadConfig(t *testing.T) {
+	factories, err := componenttest.NopFactories()
+	require.NoError(t, err)
+
+	factory := NewFactory()
+	factories.Receivers[typeStr] = factory
+	cfg, err := configtest.LoadConfigAndValidate(path.Join(".", "testdata", "config.yaml"), factories)
+
+	require.NoError(t, err)
+	require.NotNil(t, cfg)
+
+	require.Len(t, cfg.Receivers, 2)
+
+	r0 := cfg.Receivers[config.NewID(typeStr)]
+	assert.Equal(t, factory.CreateDefaultConfig(), r0)
+
+	r1 := cfg.Receivers[config.NewIDWithName(typeStr, "one")].(*Config)
+	assert.Equal(t,
+		&Config{
+			ReceiverSettings:        config.NewReceiverSettings(config.NewIDWithName(typeStr, "one")),
+			RLPGatewayURL:           "https://log-stream.sys.example.internal",
+			RLPGatewaySkipTLSVerify: true,
+			RLPGatewayShardID:       "otel-test",
+			UAAUrl:                  "https://uaa.sys.example.internal",
+			UAASkipTLSVerify:        true,
+			UAAUsername:             "admin",
+			UAAPassword:             "test",
+			HTTPTimeout:             time.Second * 20,
+		}, r1)
+}

receiver/cloudfoundryreceiver/doc.go

@@ -0,0 +1,20 @@
+// Copyright 2019, 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 cloudfoundryreceiver implements a receiver that can be used by the
+// Opentelemetry collector to receive Cloud Foundry metrics via its Reverse
+// Log Proxy (RLP) Gateway component. The protocol is handled by the
+// go-loggregator library, which uses HTTP to connect to the gateway and receive
+// JSON-protobuf encoded v2 Envelope messages as documented by loggregator-api.
+package cloudfoundryreceiver

receiver/cloudfoundryreceiver/factory.go

@@ -0,0 +1,64 @@
+// Copyright 2019, 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 cloudfoundryreceiver
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/receiver/receiverhelper"
+)
+
+// This file implements factory for Cloud Foundry receiver.
+
+const (
+	typeStr                  = "cloudfoundry"
+	defaultUAAUsername       = "admin"
+	defaultRLPGatewayShardID = "opentelemetry"
+	defaultURL               = "https://localhost"
+)
+
+// NewFactory creates a factory for collectd receiver.
+func NewFactory() component.ReceiverFactory {
+	return receiverhelper.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		receiverhelper.WithMetrics(createMetricsReceiver))
+}
+
+func createDefaultConfig() config.Receiver {
+	return &Config{
+		ReceiverSettings:        config.NewReceiverSettings(config.NewID(typeStr)),
+		RLPGatewayURL:           defaultURL,
+		RLPGatewaySkipTLSVerify: false,
+		RLPGatewayShardID:       defaultRLPGatewayShardID,
+		UAAUsername:             defaultUAAUsername,
+		UAAPassword:             "",
+		UAAUrl:                  defaultURL,
+		UAASkipTLSVerify:        false,
+	}
+}
+
+func createMetricsReceiver(
+	_ context.Context,
+	params component.ReceiverCreateSettings,
+	cfg config.Receiver,
+	nextConsumer consumer.Metrics,
+) (component.MetricsReceiver, error) {
+	c := cfg.(*Config)
+	return newCloudFoundryReceiver(params.Logger, *c, nextConsumer)
+}

receiver/cloudfoundryreceiver/factory_test.go

@@ -0,0 +1,43 @@
+// Copyright 2019, 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 cloudfoundryreceiver
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config/configcheck"
+	"go.opentelemetry.io/collector/consumer/consumertest"
+)
+
+func TestCreateDefaultConfig(t *testing.T) {
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	require.NotNil(t, cfg, "failed to create default config")
+	assert.NoError(t, configcheck.ValidateConfig(cfg))
+}
+
+func TestCreateReceiver(t *testing.T) {
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+
+	params := componenttest.NewNopReceiverCreateSettings()
+	tReceiver, err := factory.CreateMetricsReceiver(context.Background(), params, cfg, consumertest.NewNop())
+	assert.NoError(t, err)
+	assert.NotNil(t, tReceiver, "receiver creation failed")
+}