[extension/observer/docker, receiver/dockerstats] Add hint about api_…

…version (#34043)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->

Adds a hint like this to `api_version`:
```
Hint: You may want to wrap the 'api_version' value in quotes (api_version: "1.25")
```

**Testing:**
<details>
<summary>docker_stats config and output</summary>

#### Config

```yaml
receivers:
  docker_stats:
    collection_interval: 2s
    api_version: 1.25 # Floating value

exporters:
  nop:

service:
  pipelines:
    metrics:
      receivers: [docker_stats]
      exporters: [nop]
```

#### Output
```
Error: failed to get config: cannot unmarshal the configuration: 1 error(s) decoding:

* error decoding 'receivers': error reading configuration for "docker_stats": 1 error(s) decoding:

* 'api_version' expected type 'string', got unconvertible type 'float64', value: '1.25'.

Hint: You may want to wrap the 'api_version' value in quotes (api_version: "1.25")

Hint: Temporarily restore the previous behavior by disabling 
      the `confmap.strictlyTypedInput` feature gate. More details at:
      open-telemetry/opentelemetry-collector#10552
```


</details>


<details>
<summary>docker_observer config and output</summary>

```yaml
receivers:
  nop:

exporters:
  nop:

extensions:
  docker_observer:
    api_version: 1.25

service:
  extensions: [docker_observer]
  pipelines:
    metrics:
      receivers: [nop]
      exporters: [nop]
```

```
Error: failed to get config: cannot unmarshal the configuration: 1 error(s) decoding:

* error decoding 'extensions': error reading configuration for "docker_observer": 1 error(s) decoding:

* 'api_version' expected type 'string', got unconvertible type 'float64', value: '1.25'.

Hint: You may want to wrap the 'api_version' value in quotes (api_version: "1.25")

Hint: Temporarily restore the previous behavior by disabling 
      the `confmap.strictlyTypedInput` feature gate. More details at:
      open-telemetry/opentelemetry-collector#10552
```

</details>

.chloggen/mx-psi_api-version-explicit-error-observer.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: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: dockerobserver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add hint to error when using float for `api_version` field
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34043]
+
+# (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: []

.chloggen/mx-psi_api-version-explicit-error.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: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: dockerstatsreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add hint to error when using float for `api_version` field
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34043]
+
+# (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: []

extension/observer/dockerobserver/config.go

@@ -8,6 +8,8 @@ import (
 	"fmt"
 	"time"
 
+	"go.opentelemetry.io/collector/confmap"
+
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/docker"
 )
 
@@ -64,3 +66,18 @@ func (config Config) Validate() error {
 	}
 	return nil
 }
+
+func (config *Config) Unmarshal(conf *confmap.Conf) error {
+	err := conf.Unmarshal(config)
+	if err != nil {
+		if floatAPIVersion, ok := conf.Get("api_version").(float64); ok {
+			return fmt.Errorf(
+				"%w.\n\nHint: You may want to wrap the 'api_version' value in quotes (api_version: \"%1.2f\")",
+				err,
+				floatAPIVersion,
+			)
+		}
+		return err
+	}
+	return nil
+}

extension/observer/dockerobserver/config_test.go

@@ -11,6 +11,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap"
 	"go.opentelemetry.io/collector/confmap/confmaptest"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/observer/dockerobserver/internal/metadata"
@@ -74,14 +75,33 @@ func TestValidateConfig(t *testing.T) {
 	assert.Nil(t, component.ValidateConfig(cfg))
 }
 
-func loadConfig(t testing.TB, id component.ID) *Config {
-	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+func loadConf(t testing.TB, path string, id component.ID) *confmap.Conf {
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", path))
 	require.NoError(t, err)
-	factory := NewFactory()
-	cfg := factory.CreateDefaultConfig()
 	sub, err := cm.Sub(id.String())
 	require.NoError(t, err)
-	require.NoError(t, sub.Unmarshal(cfg))
+	return sub
+}
 
+func loadConfig(t testing.TB, id component.ID) *Config {
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	sub := loadConf(t, "config.yaml", id)
+	require.NoError(t, sub.Unmarshal(cfg))
 	return cfg.(*Config)
 }
+
+func TestApiVersionCustomError(t *testing.T) {
+	sub := loadConf(t, "api_version_float.yaml", component.NewID(metadata.Type))
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	err := sub.Unmarshal(cfg)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(),
+		`Hint: You may want to wrap the 'api_version' value in quotes (api_version: "1.40")`,
+	)
+
+	sub = loadConf(t, "api_version_string.yaml", component.NewID(metadata.Type))
+	err = sub.Unmarshal(cfg)
+	require.NoError(t, err)
+}

extension/observer/dockerobserver/testdata/api_version_float.yaml

@@ -0,0 +1,2 @@
+docker_observer:
+  api_version: 1.40

extension/observer/dockerobserver/testdata/api_version_string.yaml

@@ -0,0 +1,2 @@
+docker_observer:
+  api_version: "1.40"

receiver/dockerstatsreceiver/config.go

@@ -5,8 +5,10 @@ package dockerstatsreceiver // import "github.com/open-telemetry/opentelemetry-c
 
 import (
 	"errors"
+	"fmt"
 
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap"
 	"go.opentelemetry.io/collector/receiver/scraperhelper"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/internal/docker"
@@ -54,3 +56,18 @@ func (config Config) Validate() error {
 	}
 	return nil
 }
+
+func (config *Config) Unmarshal(conf *confmap.Conf) error {
+	err := conf.Unmarshal(config)
+	if err != nil {
+		if floatAPIVersion, ok := conf.Get("api_version").(float64); ok {
+			return fmt.Errorf(
+				"%w.\n\nHint: You may want to wrap the 'api_version' value in quotes (api_version: \"%1.2f\")",
+				err,
+				floatAPIVersion,
+			)
+		}
+		return err
+	}
+	return nil
+}

receiver/dockerstatsreceiver/config_test.go

@@ -13,12 +13,21 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/confmap"
 	"go.opentelemetry.io/collector/confmap/confmaptest"
 	"go.opentelemetry.io/collector/receiver/scraperhelper"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/dockerstatsreceiver/internal/metadata"
 )
 
+func loadConf(t testing.TB, path string, id component.ID) *confmap.Conf {
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", path))
+	require.NoError(t, err)
+	sub, err := cm.Sub(id.String())
+	require.NoError(t, err)
+	return sub
+}
+
 func TestLoadConfig(t *testing.T) {
 	t.Parallel()
 
@@ -72,14 +81,9 @@ func TestLoadConfig(t *testing.T) {
 
 	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)
-
+			sub := loadConf(t, "config.yaml", tt.id)
 			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))
@@ -108,3 +112,18 @@ func TestValidateErrors(t *testing.T) {
 	}
 	assert.Equal(t, `"collection_interval": requires positive value`, component.ValidateConfig(cfg).Error())
 }
+
+func TestApiVersionCustomError(t *testing.T) {
+	sub := loadConf(t, "api_version_float.yaml", component.NewID(metadata.Type))
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	err := sub.Unmarshal(cfg)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(),
+		`Hint: You may want to wrap the 'api_version' value in quotes (api_version: "1.40")`,
+	)
+
+	sub = loadConf(t, "api_version_string.yaml", component.NewID(metadata.Type))
+	err = sub.Unmarshal(cfg)
+	require.NoError(t, err)
+}

receiver/dockerstatsreceiver/testdata/api_version_float.yaml

@@ -0,0 +1,2 @@
+docker_stats:
+  api_version: 1.40

receiver/dockerstatsreceiver/testdata/api_version_string.yaml

@@ -0,0 +1,2 @@
+docker_stats:
+  api_version: "1.40"