78 lines
2.5 KiB
Go
78 lines
2.5 KiB
Go
// Copyright 2026 Alibaba Group
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package agentproduct defines the caller-provided Agent product identity
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// used for outbound observability and IM message display.
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package agentproduct
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import (
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"errors"
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"os"
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"regexp"
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"strings"
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)
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const (
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// EnvName is the runtime override for the Agent product identity.
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EnvName = "DWS_AGENT_PRODUCT"
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// HeaderName is the observability header used for the Agent product.
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// It is intentionally separate from the routing/PAT claw-type header.
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HeaderName = "x-dws-agent-product"
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// MaxValueBytes bounds the value because it is attached to every outbound
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// MCP request. Supported values are ASCII, so bytes and characters match.
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MaxValueBytes = 64
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)
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// ErrInvalid is returned when an Agent product value is unsafe or does not
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// match the supported wire format. The error intentionally excludes the raw
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// caller-controlled value.
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var ErrInvalid = errors.New("invalid agent product")
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var valuePattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9_-]*$`)
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// Parse normalizes and validates a caller-provided Agent product. Only
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// surrounding ASCII spaces and tabs are trimmed; other control or Unicode
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// whitespace remains visible to validation and is rejected. An unset or
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// ASCII-whitespace-only value means "use the edition default".
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func Parse(raw string) (string, error) {
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if strings.ContainsAny(raw, "\r\n") {
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return "", ErrInvalid
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}
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value := strings.Trim(raw, " \t")
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if value == "" {
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return "", nil
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}
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if len(value) > MaxValueBytes {
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return "", ErrInvalid
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}
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if !valuePattern.MatchString(value) {
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return "", ErrInvalid
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}
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return value, nil
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}
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// ResolveFromEnv returns the validated DWS_AGENT_PRODUCT value, or fallback
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// when the environment variable is unset or empty. Invalid caller input is
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// returned as an error so command entrypoints can fail before network access.
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func ResolveFromEnv(fallback string) (string, error) {
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value, err := Parse(os.Getenv(EnvName))
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if err != nil {
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return "", err
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}
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if value == "" {
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return fallback, nil
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}
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return value, nil
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}
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