fix(inputs.mock): Plugin not aligned with documentation (#13997)

plugins/inputs/mock/README.md

@@ -29,26 +29,25 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
   # "key" = "value"
 
   ## One or more mock data fields *must* be defined.
-  ##
-  ## [[inputs.mock.constant]]
-  ##   name = "constant"
-  ##   value = value_of_any_type
-  ## [[inputs.mock.random]]
-  ##   name = "rand"
-  ##   min = 1.0
-  ##   max = 6.0
-  ## [[inputs.mock.sine_wave]]
-  ##   name = "wave"
-  ##   amplitude = 1.0
-  ##   period = 0.5
-  ## [[inputs.mock.step]]
-  ##   name = "plus_one"
-  ##   start = 0.0
-  ##   step = 1.0
-  ## [[inputs.mock.stock]]
-  ##   name = "abc"
-  ##   price = 50.00
-  ##   volatility = 0.2
+  # [[inputs.mock.constant]]
+  #   name = "constant"
+  #   value = value_of_any_type
+  # [[inputs.mock.random]]
+  #   name = "rand"
+  #   min = 1.0
+  #   max = 6.0
+  # [[inputs.mock.sine_wave]]
+  #   name = "wave"
+  #   amplitude = 1.0
+  #   period = 0.5
+  # [[inputs.mock.step]]
+  #   name = "plus_one"
+  #   start = 0.0
+  #   step = 1.0
+  # [[inputs.mock.stock]]
+  #   name = "abc"
+  #   price = 50.00
+  #   volatility = 0.2
 ```
 
 The mock plugin only requires that:

plugins/inputs/mock/mock.go

@@ -49,8 +49,11 @@ type step struct {
 	latest float64
 
 	Name  string  `toml:"name"`
-	Start float64 `toml:"min"`
-	Step  float64 `toml:"max"`
+	Start float64 `toml:"start"`
+	Step  float64 `toml:"step"`
+
+	Min float64 `toml:"min" deprecated:"1.28.2;use 'start' instead"`
+	Max float64 `toml:"max" deprecated:"1.28.2;use 'step' instead"`
 }
 
 type stock struct {
@@ -67,6 +70,17 @@ func (*Mock) SampleConfig() string {
 
 func (m *Mock) Init() error {
 	m.rand = rand.New(rand.NewSource(time.Now().UnixNano())) //nolint:gosec // G404: not security critical
+
+	// backward compatibility
+	for _, step := range m.Step {
+		if step.Min != 0 && step.Start == 0 {
+			step.Start = step.Min
+		}
+		if step.Max != 0 && step.Step == 0 {
+			step.Step = step.Max
+		}
+	}
+
 	return nil
 }
 

plugins/inputs/mock/sample.conf

@@ -8,23 +8,22 @@
   # "key" = "value"
 
   ## One or more mock data fields *must* be defined.
-  ##
-  ## [[inputs.mock.constant]]
-  ##   name = "constant"
-  ##   value = value_of_any_type
-  ## [[inputs.mock.random]]
-  ##   name = "rand"
-  ##   min = 1.0
-  ##   max = 6.0
-  ## [[inputs.mock.sine_wave]]
-  ##   name = "wave"
-  ##   amplitude = 1.0
-  ##   period = 0.5
-  ## [[inputs.mock.step]]
-  ##   name = "plus_one"
-  ##   start = 0.0
-  ##   step = 1.0
-  ## [[inputs.mock.stock]]
-  ##   name = "abc"
-  ##   price = 50.00
-  ##   volatility = 0.2
+  # [[inputs.mock.constant]]
+  #   name = "constant"
+  #   value = value_of_any_type
+  # [[inputs.mock.random]]
+  #   name = "rand"
+  #   min = 1.0
+  #   max = 6.0
+  # [[inputs.mock.sine_wave]]
+  #   name = "wave"
+  #   amplitude = 1.0
+  #   period = 0.5
+  # [[inputs.mock.step]]
+  #   name = "plus_one"
+  #   start = 0.0
+  #   step = 1.0
+  # [[inputs.mock.stock]]
+  #   name = "abc"
+  #   price = 50.00
+  #   volatility = 0.2