function/parse_duration: Add duration parsing function (#350)

* function/parse_duration: Add duration parsing function

* Renamed parse_duration to duration_parse

* Added link to Go duration strings in duration_parse function summary and description

* Use static assertions in duration_parse tests instead

* Added CHANGELOG entry

* Removed unused import

* Updated time.ParseDuration

* Output of make generate

.changes/unreleased/FEATURES-20250123-191529.yaml

@@ -0,0 +1,5 @@
+kind: FEATURES
+body: 'functions/duration_parse: Added a new `duration_parse` function that parses [Go duration strings](https://pkg.go.dev/time#ParseDuration).'
+time: 2025-01-23T19:15:29.754845+01:00
+custom:
+    Issue: "350"

docs/functions/duration_parse.md

@@ -0,0 +1,54 @@
+---
+page_title: "duration_parse function - terraform-provider-time"
+subcategory: ""
+description: |-
+  Parse a Go duration string https://pkg.go.dev/time#ParseDuration into an object
+---
+
+# function: duration_parse
+
+Given a [Go duration string](https://pkg.go.dev/time#ParseDuration), will parse and return an object representation of that duration.
+
+## Example Usage
+
+```terraform
+# Configuration using provider functions must include required_providers configuration.
+terraform {
+  required_providers {
+    time = {
+      source = "hashicorp/time"
+      # Setting the provider version is a strongly recommended practice
+      # version = "..."
+    }
+  }
+  # Provider functions require Terraform 1.8 and later.
+  required_version = ">= 1.8.0"
+}
+
+output "example_output" {
+  value = provider::time::duration_parse("1h")
+}
+```
+
+## Signature
+
+<!-- signature generated by tfplugindocs -->
+```text
+duration_parse(duration string) object
+```
+
+## Arguments
+
+<!-- arguments generated by tfplugindocs -->
+1. `duration` (String) Go time package duration string to parse
+
+
+## Return Type
+
+The `object` returned from `duration_parse` has the following attributes:
+- `hours` (Number) The duration as a floating point number of hours.
+- `minutes` (Number) The duration as a floating point number of minutes.
+- `seconds` (Number) The duration as a floating point number of seconds.
+- `milliseconds` (Number) The duration as an integer number of milliseconds.
+- `microseconds` (Number) The duration as an integer number of microseconds.
+- `nanoseconds` (Number) The duration as an integer number of nanoseconds.

examples/functions/duration_parse/function.tf

@@ -0,0 +1,16 @@
+# Configuration using provider functions must include required_providers configuration.
+terraform {
+  required_providers {
+    time = {
+      source = "hashicorp/time"
+      # Setting the provider version is a strongly recommended practice
+      # version = "..."
+    }
+  }
+  # Provider functions require Terraform 1.8 and later.
+  required_version = ">= 1.8.0"
+}
+
+output "example_output" {
+  value = provider::time::duration_parse("1h")
+}

internal/provider/function_duration_parse.go

@@ -0,0 +1,91 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package provider
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/function"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-log/tflog"
+)
+
+var durationParseReturnAttrTypes = map[string]attr.Type{
+	"hours":        types.Float64Type,
+	"minutes":      types.Float64Type,
+	"seconds":      types.Float64Type,
+	"milliseconds": types.Int64Type,
+	"microseconds": types.Int64Type,
+	"nanoseconds":  types.Int64Type,
+}
+
+var _ function.Function = &DurationParseFunction{}
+
+type DurationParseFunction struct{}
+
+func NewDurationParseFunction() function.Function {
+	return &DurationParseFunction{}
+}
+
+func (f *DurationParseFunction) Metadata(ctx context.Context, req function.MetadataRequest, resp *function.MetadataResponse) {
+	resp.Name = "duration_parse"
+}
+
+func (f *DurationParseFunction) Definition(ctx context.Context, req function.DefinitionRequest, resp *function.DefinitionResponse) {
+	resp.Definition = function.Definition{
+		Summary:     "Parse a [Go duration string](https://pkg.go.dev/time#ParseDuration) into an object",
+		Description: "Given a [Go duration string](https://pkg.go.dev/time#ParseDuration), will parse and return an object representation of that duration.",
+
+		Parameters: []function.Parameter{
+			function.StringParameter{
+				Name:        "duration",
+				Description: "Go time package duration string to parse",
+			},
+		},
+		Return: function.ObjectReturn{
+			AttributeTypes: durationParseReturnAttrTypes,
+		},
+	}
+}
+
+func (f *DurationParseFunction) Run(ctx context.Context, req function.RunRequest, resp *function.RunResponse) {
+	var input string
+
+	resp.Error = req.Arguments.Get(ctx, &input)
+	if resp.Error != nil {
+		return
+	}
+
+	duration, err := time.ParseDuration(input)
+	if err != nil {
+		// Intentionally not including the Go parse error in the return diagnostic, as the message is based on a Go-specific
+		// reference time that may be unfamiliar to practitioners
+		tflog.Error(ctx, fmt.Sprintf("failed to parse duration string, underlying time.Duration error: %s", err.Error()))
+
+		resp.Error = function.NewArgumentFuncError(0, fmt.Sprintf("Error parsing duration string: %q is not a valid duration string", input))
+		return
+	}
+
+	durationObj, diags := types.ObjectValue(
+		durationParseReturnAttrTypes,
+		map[string]attr.Value{
+			"hours":        types.Float64Value(duration.Hours()),
+			"minutes":      types.Float64Value(duration.Minutes()),
+			"seconds":      types.Float64Value(duration.Seconds()),
+			"milliseconds": types.Int64Value(duration.Milliseconds()),
+			"microseconds": types.Int64Value(duration.Microseconds()),
+			"nanoseconds":  types.Int64Value(duration.Nanoseconds()),
+		},
+	)
+
+	resp.Error = function.FuncErrorFromDiags(ctx, diags)
+	if resp.Error != nil {
+		return
+	}
+
+	resp.Error = resp.Result.Set(ctx, &durationObj)
+}

internal/provider/function_duration_parse_test.go

@@ -0,0 +1,125 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package provider
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+	"github.com/hashicorp/terraform-plugin-testing/knownvalue"
+	"github.com/hashicorp/terraform-plugin-testing/plancheck"
+	"github.com/hashicorp/terraform-plugin-testing/tfversion"
+)
+
+func TestDurationParse_valid(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(tfversion.Version1_8_0),
+		},
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("1h")
+				}
+				`,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectKnownOutputValue("test", knownvalue.ObjectExact(
+							map[string]knownvalue.Check{
+								"hours":        knownvalue.Float64Exact(1),
+								"minutes":      knownvalue.Float64Exact(60),
+								"seconds":      knownvalue.Float64Exact(3600),
+								"milliseconds": knownvalue.Int64Exact(3600000),
+								"microseconds": knownvalue.Int64Exact(3600000000),
+								"nanoseconds":  knownvalue.Int64Exact(3600000000000),
+							},
+						)),
+					},
+				},
+			},
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("60m")
+				}
+				`,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectEmptyPlan(),
+					},
+				},
+			},
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("3600s")
+				}
+				`,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectEmptyPlan(),
+					},
+				},
+			},
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("3600000ms")
+				}
+				`,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectEmptyPlan(),
+					},
+				},
+			},
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("3600000000us")
+				}
+				`,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectEmptyPlan(),
+					},
+				},
+			},
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("3600000000000ns")
+				}
+				`,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectEmptyPlan(),
+					},
+				},
+			},
+		},
+	})
+}
+
+func TestDurationParse_invalid(t *testing.T) {
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(tfversion.Version1_8_0),
+		},
+		ProtoV5ProviderFactories: protoV5ProviderFactories(),
+		Steps: []resource.TestStep{
+			{
+				Config: `
+				output "test" {
+					value = provider::time::duration_parse("abcdef")
+				}
+				`,
+				ExpectError: regexp.MustCompile(`"abcdef" is not a valid duration string.`),
+			},
+		},
+	})
+}

internal/provider/provider.go

@@ -60,6 +60,7 @@ func (p *timeProvider) Schema(context.Context, provider.SchemaRequest, *provider
 
 func (p *timeProvider) Functions(ctx context.Context) []func() function.Function {
 	return []func() function.Function{
+		NewDurationParseFunction,
 		NewRFC3339ParseFunction,
 	}
 }

templates/functions/duration_parse.md.tmpl

@@ -0,0 +1,37 @@
+---
+page_title: "{{.Name}} {{.Type}} - {{.ProviderName}}"
+subcategory: ""
+description: |-
+{{ .Summary | plainmarkdown | trimspace | prefixlines "  " }}
+---
+
+# {{.Type}}: {{.Name}}
+
+{{ .Description | trimspace }}
+
+{{ if .HasExample -}}
+## Example Usage
+
+{{tffile .ExampleFile }}
+{{- end }}
+
+## Signature
+
+{{ .FunctionSignatureMarkdown }}
+
+## Arguments
+
+{{ .FunctionArgumentsMarkdown }}
+{{ if .HasVariadic -}}
+{{ .FunctionVariadicArgumentMarkdown }}
+{{- end }}
+
+## Return Type
+
+The `object` returned from `duration_parse` has the following attributes:
+- `hours` (Number) The duration as a floating point number of hours.
+- `minutes` (Number) The duration as a floating point number of minutes.
+- `seconds` (Number) The duration as a floating point number of seconds.
+- `milliseconds` (Number) The duration as an integer number of milliseconds.
+- `microseconds` (Number) The duration as an integer number of microseconds.
+- `nanoseconds` (Number) The duration as an integer number of nanoseconds.