[receiver/couchdb] Initialize component (#6815)

* establish couchdb codebase

* add in pr feedback

* clean up names/format

* fix linting ci

* add couchdbreceiver to verisons

* remove host validation

* fix nit

* Update receiver/couchdbreceiver/README.md

Co-authored-by: Daniel Jaglowski <dan.jaglowski@bluemedora.com>

* add check for default endpoint on CreateDefaultConfig

* add missing receivers in versions

Co-authored-by: Daniel Jaglowski <dan.jaglowski@bluemedora.com>

.github/CODEOWNERS

@@ -96,6 +96,7 @@ receiver/awsxrayreceiver/                            @open-telemetry/collector-c
 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/couchdbreceiver/                            @open-telemetry/collector-contrib-approvers @djaglowski
 receiver/dockerstatsreceiver/                        @open-telemetry/collector-contrib-approvers @rmfitzpatrick
 receiver/dotnetdiagnosticsreceiver/                  @open-telemetry/collector-contrib-approvers @pmcollins @davmason
 receiver/filelogreceiver/                            @open-telemetry/collector-contrib-approvers @djaglowski

.github/dependabot.yml

@@ -421,6 +421,10 @@ updates:
     directory: "/receiver/collectdreceiver"
     schedule:
       interval: "weekly"
+  - package-ecosystem: "gomod"
+    directory: "/receiver/couchdbreceiver"
+    schedule:
+      interval: "weekly"
   - package-ecosystem: "gomod"
     directory: "/receiver/dockerstatsreceiver"
     schedule:

receiver/couchdbreceiver/Makefile

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

receiver/couchdbreceiver/README.md

@@ -0,0 +1,42 @@
+# CouchDB Receiver
+
+This receiver fetches stats from a couchdb server using the `/_node/{node-name}/_stats/couchdb` [endpoint](https://docs.couchdb.org/en/latest/api/server/common.html#node-node-name-stats).
+
+Supported pipeline types: `metrics`
+
+> :construction: This receiver is in **BETA**. Configuration fields and metric data model are subject to change.
+
+## Prerequisites
+
+This receiver supports Couchdb versions `2.3+` and `3.1+`.
+
+## Configuration
+
+The following settings are required:
+- `username`
+- `password`
+
+The following settings are optional:
+- `endpoint` (default: `http://localhost:5984`): The URL of the couchdb endpoint
+
+- `all_nodes` (default: false): When `all_nodes` is false, this receiver collects a single node stats with {node-name} replaced with _local. When `all_nodes` is true, then this receiver fetches all known connected nodes using the `/_membership` [endpoint](docs.couchdb.org/en/stable/cluster/nodes.html#node-management) to then collect stats for each {node-name} found.
+
+- `collection_interval` (default = `10s`): This receiver collects metrics on an interval. This value must be a string readable by Golang's [time.ParseDuration](https://pkg.go.dev/time#ParseDuration). Valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`.
+
+### Example Configuration
+
+```yaml
+receivers:
+  couchdb:
+    endpoint: http://localhost:5984
+    username: otelu
+    password: $COUCHDB_PASSWORD
+    all_nodes: false
+    collection_interval: 10s
+```
+
+The full list of settings exposed for this receiver are documented [here](./config.go) with detailed sample configurations [here](./testdata/config.yaml). TLS config is documented further under the [opentelemetry collector's configtls package](https://github.com/open-telemetry/opentelemetry-collector/blob/main/config/configtls/README.md).
+
+## Metrics
+
+Details about the metrics produced by this receiver can be found in [metadata.yaml](./metadata.yaml)

receiver/couchdbreceiver/config.go

@@ -0,0 +1,62 @@
+// 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 couchdbreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/couchdbreceiver"
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/receiver/scraperhelper"
+	"go.uber.org/multierr"
+)
+
+const defaultEndpoint = "http://localhost:5984"
+
+var (
+	// Errors for missing required config fields.
+	errMissingUsername = errors.New(`no "username" specified in config`)
+	errMissingPassword = errors.New(`no "password" specified in config`)
+
+	// Errors for invalid url components in the endpoint.
+	errInvalidEndpoint = errors.New(`"endpoint" %q must be in the form of <scheme>://<hostname>:<port>`)
+)
+
+// Config defines the configuration for the various elements of the receiver agent.
+type Config struct {
+	scraperhelper.ScraperControllerSettings `mapstructure:",squash"`
+	confighttp.HTTPClientSettings           `mapstructure:",squash"`
+	Username                                string `mapstructure:"username"`
+	Password                                string `mapstructure:"password"`
+	AllNodes                                bool   `mapstructure:"all_nodes"`
+}
+
+// Validate validates missing and invalid configuration fields.
+func (cfg *Config) Validate() error {
+	var err error
+	if cfg.Username == "" {
+		err = multierr.Append(err, errMissingUsername)
+	}
+	if cfg.Password == "" {
+		err = multierr.Append(err, errMissingPassword)
+	}
+
+	_, parseErr := url.Parse(cfg.Endpoint)
+	if parseErr != nil {
+		err = multierr.Append(err, fmt.Errorf(errInvalidEndpoint.Error(), parseErr))
+	}
+	return err
+}

receiver/couchdbreceiver/config_test.go

@@ -0,0 +1,100 @@
+// 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 couchdbreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/couchdbreceiver"
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.uber.org/multierr"
+)
+
+func TestValidate(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		cfg         *Config
+		expectedErr error
+	}{
+		{
+			desc: "missing username, password and invalid endpoint",
+			cfg: &Config{
+				HTTPClientSettings: confighttp.HTTPClientSettings{
+					Endpoint: "http://localhost :5984",
+				},
+			},
+			expectedErr: multierr.Combine(
+				errMissingUsername,
+				errMissingPassword,
+				fmt.Errorf(errInvalidEndpoint.Error(), "parse \"http://localhost :5984\": invalid character \" \" in host name"),
+			),
+		},
+		{
+			desc: "missing password and invalid endpoint",
+			cfg: &Config{
+				HTTPClientSettings: confighttp.HTTPClientSettings{
+					Endpoint: "http://localhost :5984",
+				},
+				Username: "otelu",
+			},
+			expectedErr: multierr.Combine(
+				errMissingPassword,
+				fmt.Errorf(errInvalidEndpoint.Error(), "parse \"http://localhost :5984\": invalid character \" \" in host name"),
+			),
+		},
+		{
+			desc: "missing username and invalid endpoint",
+			cfg: &Config{
+				HTTPClientSettings: confighttp.HTTPClientSettings{
+					Endpoint: "http://localhost :5984",
+				},
+				Password: "otelp",
+			},
+			expectedErr: multierr.Combine(
+				errMissingUsername,
+				fmt.Errorf(errInvalidEndpoint.Error(), "parse \"http://localhost :5984\": invalid character \" \" in host name"),
+			),
+		},
+		{
+			desc: "invalid endpoint",
+			cfg: &Config{
+				Username: "otel",
+				Password: "otel",
+				HTTPClientSettings: confighttp.HTTPClientSettings{
+					Endpoint: "http://localhost :5984",
+				},
+			},
+			expectedErr: fmt.Errorf(errInvalidEndpoint.Error(), "parse \"http://localhost :5984\": invalid character \" \" in host name"),
+		},
+		{
+			desc: "no error",
+			cfg: &Config{
+				Username: "otel",
+				Password: "otel",
+				HTTPClientSettings: confighttp.HTTPClientSettings{
+					Endpoint: "http://localhost:5984",
+				},
+			},
+			expectedErr: nil,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			actualErr := tc.cfg.Validate()
+			require.Equal(t, tc.expectedErr, actualErr)
+		})
+	}
+}

receiver/couchdbreceiver/documentation.md

@@ -0,0 +1,15 @@
+[comment]: <> (Code generated by mdatagen. DO NOT EDIT.)
+
+# couchdbreceiver
+
+## Metrics
+
+These are the metrics available for this scraper.
+
+| Name | Description | Unit | Type | Attributes |
+| ---- | ----------- | ---- | ---- | ---------- |
+
+## Attributes
+
+| Name | Description |
+| ---- | ----------- |

receiver/couchdbreceiver/factory.go

@@ -0,0 +1,63 @@
+// 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 couchdbreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/couchdbreceiver"
+
+//go:generate mdatagen metadata.yaml
+
+import (
+	"context"
+	"time"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/config/configtls"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/receiver/receiverhelper"
+	"go.opentelemetry.io/collector/receiver/scraperhelper"
+)
+
+const (
+	typeStr = "couchdb"
+)
+
+func NewFactory() component.ReceiverFactory {
+	return receiverhelper.NewFactory(
+		typeStr,
+		createDefaultConfig,
+		receiverhelper.WithMetrics(createMetricsReceiver))
+}
+
+func createDefaultConfig() config.Receiver {
+	return &Config{
+		ScraperControllerSettings: scraperhelper.ScraperControllerSettings{
+			ReceiverSettings:   config.NewReceiverSettings(config.NewComponentID(typeStr)),
+			CollectionInterval: 10 * time.Second,
+		},
+		HTTPClientSettings: confighttp.HTTPClientSettings{
+			TLSSetting: configtls.TLSClientSetting{
+				Insecure:           false,
+				InsecureSkipVerify: true,
+			},
+			Endpoint: defaultEndpoint,
+			Timeout:  10 * time.Second,
+		},
+		AllNodes: false,
+	}
+}
+
+func createMetricsReceiver(_ context.Context, params component.ReceiverCreateSettings, rConf config.Receiver, consumer consumer.Metrics) (component.MetricsReceiver, error) {
+	return nil, nil
+}

receiver/couchdbreceiver/factory_test.go

@@ -0,0 +1,65 @@
+// 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 couchdbreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/couchdbreceiver"
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/consumer/consumertest"
+	"go.opentelemetry.io/collector/receiver/scraperhelper"
+)
+
+func TestType(t *testing.T) {
+	factory := NewFactory()
+	ft := factory.Type()
+	require.EqualValues(t, "couchdb", ft)
+}
+
+func TestValidConfig(t *testing.T) {
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig().(*Config)
+	cfg.Username = "otel"
+	cfg.Password = "otel"
+
+	require.EqualValues(t, defaultEndpoint, cfg.Endpoint)
+	require.NoError(t, cfg.Validate())
+}
+
+func TestCreateMetricsReceiver(t *testing.T) {
+	factory := NewFactory()
+	_, err := factory.CreateMetricsReceiver(
+		context.Background(),
+		component.ReceiverCreateSettings{},
+		&Config{
+			ScraperControllerSettings: scraperhelper.ScraperControllerSettings{
+				ReceiverSettings:   config.NewReceiverSettings(config.NewComponentID("couchdb")),
+				CollectionInterval: 10 * time.Second,
+			},
+			HTTPClientSettings: confighttp.HTTPClientSettings{
+				Endpoint: "http://localhost:5984",
+			},
+			Username: "otel",
+			Password: "otel",
+		},
+		consumertest.NewNop(),
+	)
+	require.NoError(t, err)
+}