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Merged
jar-b merged 5 commits into from
Dec 8, 2025
Merged

useragent: add FromSlice function #1389

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c0aa19d
useragent: add `FromSlice` function
jar-b Dec 3, 2025
234c90f
useragent: skip empty string check
jar-b Dec 8, 2025
ac02a7c
useragent(test): additional malformed comment cases
jar-b Dec 8, 2025
5a24a5b
useragent: move all processing to `fromAny`
jar-b Dec 8, 2025
e509f3f
useragent: tweak `from` signature
jar-b Dec 8, 2025
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49 changes: 49 additions & 0 deletions useragent/from.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,49 @@
// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package useragent

import (
"strings"

"github.com/hashicorp/aws-sdk-go-base/v2/internal/config"
"github.com/hashicorp/aws-sdk-go-base/v2/internal/slices"
)

// FromSlice applies the conversion defined in [fromString] to all elements
// of a slice
//
// Slices of types which cannot assert to a string, empty string values, and string
// values which do not match the expected `{product}/{version} ({comment})`
// pattern (where version and comment are optional) return a zero value struct.
func FromSlice[T any](sl []T) config.UserAgentProducts {
return slices.ApplyToAll(sl, func(v T) config.UserAgentProduct {
if s, ok := any(v).(string); ok && s != "" {
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@YakDriver YakDriver Dec 5, 2025

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doesn't really need the empty check since fromString checks that?

return fromString(s)
}
return config.UserAgentProduct{}
})
}

// fromString separates the provided string into the constituent parts
// expected by the UserAgentProduct struct
//
// Values which do not match the expected `{product}/{version} ({comment})`
// pattern, where version and comment are optional, return a zero value struct.
func fromString(s string) config.UserAgentProduct {
parts := strings.Split(s, "/")
switch len(parts) {
case 1:
return config.UserAgentProduct{Name: parts[0]}
case 2: //nolint: mnd
subparts := strings.Split(parts[1], "(")
if len(subparts) == 2 { //nolint: mnd
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@YakDriver YakDriver Dec 5, 2025

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Suggested change
if len(subparts) == 2 { //nolint: mnd
if len(subparts) == 2 && strings.HasSuffix(parts[1], ")") { //nolint: mnd

probably not worth "fixing" but an edge case "my-product/v1.2.3 (not a comment" that would parse wrong

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@jar-b jar-b Dec 8, 2025

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A missing closing parenthesis would still parse correctly because strings.TrimSuffix(subparts[1], ")") just does nothing. For example, this test case passes.

		{
			"malformed comment closing",
			"my-product/v1.2.3 (a comment",
			config.UserAgentProduct{
				Name:    "my-product",
				Version: "v1.2.3",
				Comment: "a comment",
			},
		},
--- PASS: Test_fromString (0.00s)

    --- PASS: Test_fromString/malformed_comment_closing (0.00s)

There is weirdness if the opening parenthesis is missed because the version and comment will get mashed together into the Version struct field, but it winds up rendering the same in the eventual UA.

In general this conversion logic is just a shim until V2 of the AWSCC provider, where we'll deprecate the structured object user_agent in favor of a list of strings. At that time the shared components in this repo can also be simplified to just pass the strings through as-is without all this extra manipulation.

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@jar-b jar-b Dec 8, 2025

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I'll still go ahead and add some test cases for malformed comment patterns, just so we document the edge cases exists and what the expected handling is.

version := strings.TrimSpace(subparts[0])
comment := strings.TrimSuffix(subparts[1], ")")
return config.UserAgentProduct{Name: parts[0], Version: version, Comment: comment}
}
return config.UserAgentProduct{Name: parts[0], Version: parts[1]}
}

return config.UserAgentProduct{}
}
116 changes: 116 additions & 0 deletions useragent/from_test.go
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@@ -0,0 +1,116 @@
// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package useragent

import (
"reflect"
"testing"

"github.com/hashicorp/aws-sdk-go-base/v2/internal/config"
)

func TestFromSlice(t *testing.T) {
t.Parallel()

tests := []struct {
name string
s []any
want config.UserAgentProducts
}{
{
"nil",
nil,
config.UserAgentProducts{},
},
{
"non-string element",
[]any{false},
config.UserAgentProducts{config.UserAgentProduct{}},
},
{
"valid string",
[]any{"my-product/v1.2.3"},
config.UserAgentProducts{
config.UserAgentProduct{
Name: "my-product",
Version: "v1.2.3",
},
},
},
{
"valid and invalid string",
[]any{"my-product/v1.2.3", "foo/bar/baz/qux"},
config.UserAgentProducts{
config.UserAgentProduct{
Name: "my-product",
Version: "v1.2.3",
},
config.UserAgentProduct{},
},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
got := FromSlice(tt.s)
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("FromSlice() = %+v, want %+v", got, tt.want)
}
})
}
}

func Test_fromString(t *testing.T) {
t.Parallel()

tests := []struct {
name string
s string
want config.UserAgentProduct
}{
{
"empty",
"",
config.UserAgentProduct{},
},
{
"name only",
"my-product",
config.UserAgentProduct{
Name: "my-product",
},
},
{
"name and version",
"my-product/v1.2.3",
config.UserAgentProduct{
Name: "my-product",
Version: "v1.2.3",
},
},
{
"name, version, and comment",
"my-product/v1.2.3 (a comment)",
config.UserAgentProduct{
Name: "my-product",
Version: "v1.2.3",
Comment: "a comment",
},
},
{
"all the slash",
"foo/bar/baz/qux",
config.UserAgentProduct{},
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
t.Parallel()
got := fromString(tt.s)
if !reflect.DeepEqual(got, tt.want) {
t.Errorf("fromString() = %+v, want %+v", got, tt.want)
}
})
}
}