[extensions/observer/cfgardenobserver] New component skeleton

    Co-authored-by: Cem Deniz Kabakci <cem.kabakci@springer.com>

.chloggen/add-cfgardenobserver.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: new_component
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: extensions/observer/cfgardenobserver
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add a new observer that discovers containers through the Garden API
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33618]
+
+# (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:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

.github/CODEOWNERS

@@ -107,6 +107,7 @@ extension/observer/ecsobserver/                                     @open-teleme
 extension/observer/ecstaskobserver/                                 @open-telemetry/collector-contrib-approvers @rmfitzpatrick
 extension/observer/hostobserver/                                    @open-telemetry/collector-contrib-approvers @MovieStoreGuy
 extension/observer/k8sobserver/                                     @open-telemetry/collector-contrib-approvers @rmfitzpatrick @dmitryax
+extension/observer/cfgardenobserver/                                @open-telemetry/collector-contrib-approvers @cemdk @tomasmota @m1rp @jriguera 
 extension/oidcauthextension/                                        @open-telemetry/collector-contrib-approvers @jpkrohling
 extension/opampcustommessages/                                      @open-telemetry/collector-contrib-approvers @BinaryFissionGames @evan-bradley
 extension/opampextension/                                           @open-telemetry/collector-contrib-approvers @portertech @evan-bradley @tigrannajaryan

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -101,6 +101,7 @@ body:
       - extension/jaegerremotesampling
       - extension/oauth2clientauth
       - extension/observer
+      - extension/observer/cfgardenobserver
       - extension/observer/dockerobserver
       - extension/observer/ecsobserver
       - extension/observer/ecstaskobserver

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -95,6 +95,7 @@ body:
       - extension/jaegerremotesampling
       - extension/oauth2clientauth
       - extension/observer
+      - extension/observer/cfgardenobserver
       - extension/observer/dockerobserver
       - extension/observer/ecsobserver
       - extension/observer/ecstaskobserver

.github/ISSUE_TEMPLATE/other.yaml

@@ -95,6 +95,7 @@ body:
       - extension/jaegerremotesampling
       - extension/oauth2clientauth
       - extension/observer
+      - extension/observer/cfgardenobserver
       - extension/observer/dockerobserver
       - extension/observer/ecsobserver
       - extension/observer/ecstaskobserver

.github/ISSUE_TEMPLATE/unmaintained.yaml

@@ -100,6 +100,7 @@ body:
       - extension/jaegerremotesampling
       - extension/oauth2clientauth
       - extension/observer
+      - extension/observer/cfgardenobserver
       - extension/observer/dockerobserver
       - extension/observer/ecsobserver
       - extension/observer/ecstaskobserver

cmd/githubgen/allowlist.txt

@@ -16,3 +16,7 @@ rlankfo
 swar8080
 zpzhuSplunk
 thmshmm
+cemdk
+tomasmota
+m1rp
+jriguera

cmd/otelcontribcol/builder-config.yaml

@@ -50,6 +50,7 @@ extensions:
     import: github.com/open-telemetry/opentelemetry-collector-contrib/extension/encoding/textencodingextension
   - gomod: github.com/open-telemetry/opentelemetry-collector-contrib/extension/encoding/zipkinencodingextension v0.103.0
     import: github.com/open-telemetry/opentelemetry-collector-contrib/extension/encoding/zipkinencodingextension
+  - gomod: github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver v0.103.0
 
 exporters:
   - gomod: go.opentelemetry.io/collector/exporter/debugexporter v0.103.0
@@ -484,3 +485,4 @@ replaces:
   - github.com/open-telemetry/opentelemetry-collector-contrib/internal/pdatautil => ../../internal/pdatautil
   - github.com/open-telemetry/opentelemetry-collector-contrib/exporter/otelarrowexporter => ../../exporter/otelarrowexporter
   - github.com/open-telemetry/opentelemetry-collector-contrib/receiver/otelarrowreceiver => ../../receiver/otelarrowreceiver
+  - github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver => ../../extension/observer/cfgardenobserver

extension/observer/cfgardenobserver/Makefile

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

extension/observer/cfgardenobserver/README.md

@@ -0,0 +1,53 @@
+# CF Garden Observer Extension
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [development]  |
+| Distributions | [] |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Aextension%2Fcfgardenobserver%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Aextension%2Fcfgardenobserver) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Aextension%2Fcfgardenobserver%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Aextension%2Fcfgardenobserver) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@crobert-1](https://www.github.com/crobert-1) |
+
+[development]: https://github.com/open-telemetry/opentelemetry-collector#development
+<!-- end autogenerated section -->
+
+Cloudfoundry is a platform as a service (PaaS) which has implemented their own container technology. The component in charge of providing a local API in each node (also known as "diego-cell") is named Garden.
+
+The `cfgarden_observer` looks at the current host to discover garden containers.
+
+## Example Config
+
+```yaml
+extensions:
+  cfgarden_observer:
+    # url of the garden socket, default to unix:///var/vcap/data/garden/garden.sock 
+    endpoint: my/path/to/garden.sock
+    # determines how often to look for changes in endpoints.
+    refresh_interval: 30s
+
+receivers:
+  receiver_creator:
+    watch_observers: [cfgarden_observer]
+    receivers:
+      prometheus_simple:
+        rule: type == "container" && name == "myapp"
+        config:
+          metrics_path: /metrics
+          endpoint: '`endpoint`'
+```
+
+### Configuration
+
+| Name             | Type   | Default                                  | Docs                                                   |
+|------------------|--------|------------------------------------------|--------------------------------------------------------|
+| refresh_interval | string | 60s                                      | Determines how often to look for changes in endpoints. |
+| endpoint         | string | unix:///var/vcap/data/garden/garden.sock | The endpoint to connect to the garden API.             |
+
+### Endpoint Variables
+
+Endpoint variables exposed by this observer are as follows.
+
+| Variable  | Description                                                                                |
+|-----------|--------------------------------------------------------------------------------------------|
+| type      | `"container"`                                                                              |
+| name      | name of the garden container associated to the port                                        |

extension/observer/cfgardenobserver/config.go

@@ -0,0 +1,26 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package cfgardenobserver // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver"
+
+import (
+	"errors" // Config defines configuration for cf garden observer.
+	"time"
+)
+
+type Config struct {
+	// The URL of the cf garden api.  Default is "unix:///var/vcap/data/garden/garden.sock"
+	Endpoint string `mapstructure:"endpoint"`
+
+	// RefreshInterval determines how frequency at which the observer
+	// needs to poll for collecting information about new processes.
+	RefreshInterval time.Duration `mapstructure:"refresh_interval"`
+}
+
+func (config Config) Validate() error {
+	if config.Endpoint == "" {
+		return errors.New("endpoint must be specified")
+	}
+
+	return nil
+}

extension/observer/cfgardenobserver/config_test.go

@@ -0,0 +1,52 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package cfgardenobserver
+
+import (
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap/confmaptest"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver/internal/metadata"
+)
+
+func TestLoadConfig(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		id       component.ID
+		expected component.Config
+	}{
+		{
+			id:       component.NewID(metadata.Type),
+			expected: NewFactory().CreateDefaultConfig(),
+		},
+		{
+			id: component.NewIDWithName(metadata.Type, "all_settings"),
+			expected: &Config{
+				Endpoint:        "unix:///var/vcap/data/garden/garden.sock",
+				RefreshInterval: 20 * time.Second,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.id.String(), func(t *testing.T) {
+			cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+			require.NoError(t, err)
+			factory := NewFactory()
+			cfg := factory.CreateDefaultConfig()
+			sub, err := cm.Sub(tt.id.String())
+			require.NoError(t, err)
+			require.NoError(t, sub.Unmarshal(cfg))
+
+			assert.NoError(t, component.ValidateConfig(cfg))
+			assert.Equal(t, tt.expected, cfg)
+		})
+	}
+}

extension/observer/cfgardenobserver/doc.go

@@ -0,0 +1,6 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:generate mdatagen metadata.yaml
+
+package cfgardenobserver // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver"

extension/observer/cfgardenobserver/extension.go

@@ -0,0 +1,42 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package cfgardenobserver // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver"
+
+import (
+	"context"
+	"time"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/extension"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer"
+)
+
+type cfGardenObserver struct {
+	*observer.EndpointsWatcher
+}
+
+var _ extension.Extension = (*cfGardenObserver)(nil)
+
+func newObserver(params extension.Settings, config *Config) (extension.Extension, error) {
+	g := &cfGardenObserver{}
+	g.EndpointsWatcher = observer.NewEndpointsWatcher(g, time.Second, params.Logger)
+
+	return g, nil
+}
+
+func (g *cfGardenObserver) Start(context.Context, component.Host) error {
+	return nil
+}
+
+func (g *cfGardenObserver) Shutdown(context.Context) error {
+	return nil
+}
+
+func (g *cfGardenObserver) ListEndpoints() []observer.Endpoint {
+	// TODO: Implement the logic to list the endpoints.
+	endpoints := make([]observer.Endpoint, 0)
+
+	return endpoints
+}

extension/observer/cfgardenobserver/extension_test.go

@@ -0,0 +1,37 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package cfgardenobserver
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/extension/extensiontest"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer"
+)
+
+func TestStartAndStopObserver(t *testing.T) {
+	factory := NewFactory()
+	params := extensiontest.NewNopSettings()
+	ext, err := newObserver(params, factory.CreateDefaultConfig().(*Config))
+	require.NoError(t, err)
+	require.NotNil(t, ext)
+
+	obvs, ok := ext.(*cfGardenObserver)
+	require.True(t, ok)
+
+	ctx := context.Background()
+	require.NoError(t, obvs.Start(ctx, componenttest.NewNopHost()))
+
+	expected := obvs.ListEndpoints()
+	want := []observer.Endpoint{}
+	require.Equal(t, want, expected)
+
+	time.Sleep(500 * time.Millisecond) // Wait a bit to sync endpoints once.
+	require.NoError(t, obvs.Shutdown(ctx))
+}

extension/observer/cfgardenobserver/factory.go

@@ -0,0 +1,42 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package cfgardenobserver // import "github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver"
+
+import (
+	"context"
+	"time"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/extension"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/cfgardenobserver/internal/metadata"
+)
+
+const (
+	defaultCollectionInterval = 60
+)
+
+// NewFactory creates a factory for HostObserver extension.
+func NewFactory() extension.Factory {
+	return extension.NewFactory(
+		metadata.Type,
+		createDefaultConfig,
+		createExtension,
+		metadata.ExtensionStability,
+	)
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{
+		RefreshInterval: defaultCollectionInterval * time.Second,
+	}
+}
+
+func createExtension(
+	_ context.Context,
+	params extension.Settings,
+	cfg component.Config,
+) (extension.Extension, error) {
+	return newObserver(params, cfg.(*Config))
+}