feat: complete the payload processing move (#602)

<!--- Provide a general summary of your changes in the Title above -->

## Description
This PR completes the payload processing move from its own repo to MaaS
repo.

## How Has This Been Tested?
<!--- Please describe in detail how you tested your changes. -->
<!--- Include details of your testing environment, and the tests you ran
to -->
<!--- see how your change affects other areas of the code, etc. -->

## Merge criteria:
<!--- This PR will be merged by any repository approver when it meets
all the points in the checklist -->
<!--- Go over all the following points, and put an `x` in all the boxes
that apply. -->

- [ ] The commits are squashed in a cohesive manner and have meaningful
messages.
- [ ] Testing instructions have been added in the PR body (for PRs
involving changes that are not immediately obvious).
- [ ] The developer has manually tested the changes and verified that
the changes work


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

## Release Notes

* **New Features**
  * Activated API key injection plugin for enhanced request security
  * Enabled support for Azure OpenAI translator
  * Enabled support for Vertex AI translator

* **Tests**
* Added comprehensive test coverage for Azure OpenAI request and
response handling
* Added comprehensive test coverage for Vertex request processing,
response transformation, error handling, and tool-call translation

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Signed-off-by: Nir Rozenbaum <nrozenba@redhat.com>

Author: nirrozenbaum

payload-processing/cmd/main.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2025.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -30,8 +30,8 @@ import (
 	"sigs.k8s.io/gateway-api-inference-extension/pkg/bbr/framework"
 
 	api_translation "github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation"
+	apikey_injection "github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/apikey-injection"
 	provider_resolver "github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/model-provider-resolver"
-	// apikey_injection "github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/apikey-injection"
 )
 
 func main() {
@@ -48,5 +48,5 @@ func main() {
 func registerPlugins() {
 	framework.Register(provider_resolver.ModelProviderResolverPluginType, provider_resolver.ModelProviderResolverFactory)
 	framework.Register(api_translation.APITranslationPluginType, api_translation.APITranslationFactory)
-	// framework.Register(apikey_injection.APIKeyInjectionPluginType, apikey_injection.APIKeyInjectionFactory)
+	framework.Register(apikey_injection.APIKeyInjectionPluginType, apikey_injection.APIKeyInjectionFactory)
 }

payload-processing/go.mod

@@ -4,6 +4,7 @@ go 1.25.0
 
 require (
 	github.com/stretchr/testify v1.11.1
+	k8s.io/api v0.35.2
 	k8s.io/apimachinery v0.35.2
 	sigs.k8s.io/controller-runtime v0.23.3
 	sigs.k8s.io/gateway-api-inference-extension v0.0.0-20260318135032-876ac9d909d0
@@ -93,7 +94,6 @@ require (
 	gopkg.in/evanphx/json-patch.v4 v4.13.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	k8s.io/api v0.35.2 // indirect
 	k8s.io/apiextensions-apiserver v0.35.2 // indirect
 	k8s.io/apiserver v0.35.2 // indirect
 	k8s.io/client-go v0.35.2 // indirect

payload-processing/pkg/plugins/api-translation/plugin.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2026 The opendatahub.io Authors.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -26,8 +26,8 @@ import (
 
 	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator"
 	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator/anthropic"
-	// "github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator/azureopenai"
-	// "github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator/vertex"
+	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator/azureopenai"
+	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator/vertex"
 	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/common/provider"
 	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/common/state"
 )
@@ -53,9 +53,9 @@ func NewAPITranslationPlugin() *APITranslationPlugin {
 			Name: APITranslationPluginType,
 		},
 		providers: map[string]translator.Translator{
-			provider.Anthropic: anthropic.NewAnthropicTranslator(),
-			// provider.AzureOpenAI: azureopenai.NewAzureOpenAITranslator(),
-			// provider.Vertex:      vertex.NewVertexTranslator(),
+			provider.Anthropic:   anthropic.NewAnthropicTranslator(),
+			provider.AzureOpenAI: azureopenai.NewAzureOpenAITranslator(),
+			provider.Vertex:      vertex.NewVertexTranslator(),
 		},
 	}
 }

payload-processing/pkg/plugins/api-translation/plugin_test.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2026 The opendatahub.io Authors.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -95,8 +95,73 @@ func TestProcessRequest_AnthropicProvider(t *testing.T) {
 	assert.NotContains(t, removed, "content-length")
 }
 
-// Azure OpenAI and Vertex tests are commented out until their translators are moved to this repo.
-// See: TestProcessRequest_AzureOpenAIProvider, TestProcessResponse_AzureOpenAI
+func TestProcessRequest_AzureOpenAIProvider(t *testing.T) {
+	p := NewAPITranslationPlugin()
+
+	cs := newCycleStateWithProvider("azure-openai")
+	req := framework.NewInferenceRequest()
+	req.Headers["authorization"] = "Bearer sk-test"
+	req.Headers["content-length"] = "200"
+	req.Body["model"] = "gpt-4o"
+	req.Body["messages"] = []any{
+		map[string]any{"role": "system", "content": "Be concise"},
+		map[string]any{"role": "user", "content": "What is 2+2?"},
+	}
+	req.Body["max_tokens"] = float64(100)
+	req.Body["temperature"] = 0.7
+
+	err := p.ProcessRequest(context.Background(), cs, req)
+	require.NoError(t, err)
+
+	// Azure OpenAI does not mutate the body — same schema as OpenAI
+	assert.False(t, req.BodyMutated())
+
+	// Original body fields are preserved
+	assert.Equal(t, "gpt-4o", req.Body["model"])
+	assert.Equal(t, float64(100), req.Body["max_tokens"])
+	assert.Equal(t, 0.7, req.Body["temperature"])
+
+	mutated := req.MutatedHeaders()
+	assert.Equal(t, "/openai/deployments/gpt-4o/chat/completions?api-version=2024-10-21", mutated[":path"])
+	assert.Equal(t, "application/json", mutated["content-type"])
+
+	removed := req.RemovedHeaders()
+	assert.Contains(t, removed, "authorization")
+	assert.NotContains(t, removed, "content-length")
+}
+
+func TestProcessResponse_AzureOpenAI(t *testing.T) {
+	p := NewAPITranslationPlugin()
+
+	cs := newCycleStateWithProvider("azure-openai")
+	cs.Write(state.ModelKey, "gpt-4o")
+
+	resp := framework.NewInferenceResponse()
+	resp.Body["id"] = "chatcmpl-abc123"
+	resp.Body["object"] = "chat.completion"
+	resp.Body["model"] = "gpt-4o"
+	resp.Body["choices"] = []any{
+		map[string]any{
+			"index": float64(0),
+			"message": map[string]any{
+				"role":    "assistant",
+				"content": "The answer is 4.",
+			},
+			"finish_reason": "stop",
+		},
+	}
+	resp.Body["usage"] = map[string]any{
+		"prompt_tokens":     float64(10),
+		"completion_tokens": float64(5),
+		"total_tokens":      float64(15),
+	}
+
+	err := p.ProcessResponse(context.Background(), cs, resp)
+	require.NoError(t, err)
+
+	// Azure OpenAI responses are already in OpenAI format — no mutation
+	assert.False(t, resp.BodyMutated())
+}
 
 func TestProcessRequest_UnknownProvider(t *testing.T) {
 	p := NewAPITranslationPlugin()
@@ -228,9 +293,161 @@ func TestProcessResponse_AnthropicToolUse(t *testing.T) {
 	assert.Equal(t, 0, tc["index"])
 }
 
-// Vertex tests are commented out until the Vertex translator is moved to this repo.
-// See: TestProcessRequest_VertexProvider, TestProcessResponse_Vertex,
-//      TestProcessResponse_VertexError, TestProcessResponse_VertexToolCall
+func TestProcessRequest_VertexProvider(t *testing.T) {
+	p := NewAPITranslationPlugin()
+
+	cs := newCycleStateWithProvider("vertex")
+	req := framework.NewInferenceRequest()
+	req.Headers["authorization"] = "Bearer sk-test"
+	req.Headers["content-length"] = "200"
+	req.Body["model"] = "gemini-2.5-flash"
+	req.Body["messages"] = []any{
+		map[string]any{"role": "system", "content": "Be concise"},
+		map[string]any{"role": "user", "content": "What is Kubernetes?"},
+	}
+	req.Body["max_tokens"] = float64(100)
+	req.Body["temperature"] = 0.7
+
+	err := p.ProcessRequest(context.Background(), cs, req)
+	require.NoError(t, err)
+
+	assert.True(t, req.BodyMutated())
+
+	contents, ok := req.Body["contents"].([]map[string]any)
+	require.True(t, ok)
+	require.Len(t, contents, 1)
+	assert.Equal(t, "user", contents[0]["role"])
+
+	sysInstruction, ok := req.Body["systemInstruction"].(map[string]any)
+	require.True(t, ok)
+	sysParts := sysInstruction["parts"].([]map[string]any)
+	assert.Equal(t, "Be concise", sysParts[0]["text"])
+
+	genConfig, ok := req.Body["generationConfig"].(map[string]any)
+	require.True(t, ok)
+	assert.Equal(t, 100, genConfig["maxOutputTokens"])
+	assert.Equal(t, 0.7, genConfig["temperature"])
+
+	mutated := req.MutatedHeaders()
+	assert.Equal(t, "/v1beta/models/gemini-2.5-flash:generateContent", mutated[":path"])
+	assert.Equal(t, "application/json", mutated["content-type"])
+
+	removed := req.RemovedHeaders()
+	assert.Contains(t, removed, "authorization")
+	assert.NotContains(t, removed, "content-length")
+}
+
+func TestProcessResponse_Vertex(t *testing.T) {
+	p := NewAPITranslationPlugin()
+
+	cs := newCycleStateWithProvider("vertex")
+	cs.Write(state.ModelKey, "gemini-2.5-flash")
+
+	resp := framework.NewInferenceResponse()
+	resp.Body["candidates"] = []any{
+		map[string]any{
+			"content": map[string]any{
+				"parts": []any{map[string]any{"text": "Kubernetes is a container orchestration platform."}},
+				"role":  "model",
+			},
+			"finishReason": "STOP",
+		},
+	}
+	resp.Body["usageMetadata"] = map[string]any{
+		"promptTokenCount":     float64(12),
+		"candidatesTokenCount": float64(8),
+		"totalTokenCount":      float64(20),
+	}
+	resp.Body["responseId"] = "resp-abc123"
+
+	err := p.ProcessResponse(context.Background(), cs, resp)
+	require.NoError(t, err)
+
+	assert.True(t, resp.BodyMutated())
+	assert.Equal(t, "chat.completion", resp.Body["object"])
+	assert.Equal(t, "gemini-2.5-flash", resp.Body["model"])
+	assert.Equal(t, "resp-abc123", resp.Body["id"])
+
+	choices := resp.Body["choices"].([]any)
+	choice := choices[0].(map[string]any)
+	msg := choice["message"].(map[string]any)
+	assert.Equal(t, "assistant", msg["role"])
+	assert.Equal(t, "Kubernetes is a container orchestration platform.", msg["content"])
+	assert.Equal(t, "stop", choice["finish_reason"])
+
+	usage := resp.Body["usage"].(map[string]any)
+	assert.Equal(t, 12, usage["prompt_tokens"])
+	assert.Equal(t, 8, usage["completion_tokens"])
+	assert.Equal(t, 20, usage["total_tokens"])
+}
+
+func TestProcessResponse_VertexError(t *testing.T) {
+	p := NewAPITranslationPlugin()
+
+	cs := newCycleStateWithProvider("vertex")
+
+	resp := framework.NewInferenceResponse()
+	resp.Body["error"] = map[string]any{
+		"code":    float64(400),
+		"message": "Invalid value at 'contents'",
+		"status":  "INVALID_ARGUMENT",
+	}
+
+	err := p.ProcessResponse(context.Background(), cs, resp)
+	require.NoError(t, err)
+
+	assert.True(t, resp.BodyMutated())
+	errObj := resp.Body["error"].(map[string]any)
+	assert.Equal(t, "INVALID_ARGUMENT", errObj["type"])
+	assert.Equal(t, "Invalid value at 'contents'", errObj["message"])
+}
+
+func TestProcessResponse_VertexToolCall(t *testing.T) {
+	p := NewAPITranslationPlugin()
+
+	cs := newCycleStateWithProvider("vertex")
+	cs.Write(state.ModelKey, "gemini-2.5-flash")
+
+	resp := framework.NewInferenceResponse()
+	resp.Body["candidates"] = []any{
+		map[string]any{
+			"content": map[string]any{
+				"parts": []any{
+					map[string]any{
+						"functionCall": map[string]any{
+							"name": "get_weather",
+							"args": map[string]any{"location": "Paris"},
+						},
+					},
+				},
+				"role": "model",
+			},
+			"finishReason": "STOP",
+		},
+	}
+	resp.Body["usageMetadata"] = map[string]any{
+		"promptTokenCount":     float64(20),
+		"candidatesTokenCount": float64(10),
+		"totalTokenCount":      float64(30),
+	}
+
+	err := p.ProcessResponse(context.Background(), cs, resp)
+	require.NoError(t, err)
+
+	assert.True(t, resp.BodyMutated())
+
+	choices := resp.Body["choices"].([]any)
+	choice := choices[0].(map[string]any)
+	msg := choice["message"].(map[string]any)
+	toolCalls := msg["tool_calls"].([]any)
+	require.Len(t, toolCalls, 1)
+
+	tc := toolCalls[0].(map[string]any)
+	assert.Equal(t, "call_0", tc["id"])
+	assert.Equal(t, 0, tc["index"])
+	fn := tc["function"].(map[string]any)
+	assert.Equal(t, "get_weather", fn["name"])
+}
 
 func TestProcessResponse_NoProviderPassthrough(t *testing.T) {
 	p := NewAPITranslationPlugin()

payload-processing/pkg/plugins/api-translation/translator/anthropic/anthropic.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2026 The opendatahub.io Authors.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@ const (
 // compile-time interface check
 var _ translator.Translator = &AnthropicTranslator{}
 
+// NewAnthropicTranslator initializes a new AnthropicTranslator and returns its pointer.
 func NewAnthropicTranslator() *AnthropicTranslator {
 	return &AnthropicTranslator{}
 }

payload-processing/pkg/plugins/api-translation/translator/anthropic/anthropic_test.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2026 The opendatahub.io Authors.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

payload-processing/pkg/plugins/api-translation/translator/azureopenai/azureopenai.go

@@ -19,6 +19,8 @@ package azureopenai
 import (
 	"fmt"
 	"regexp"
+
+	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator"
 )
 
 const (
@@ -33,8 +35,9 @@ const (
 )
 
 // compile-time interface check
-// var _ translator.Translator = &AzureOpenAITranslator{}
+var _ translator.Translator = &AzureOpenAITranslator{}
 
+// NewAzureOpenAITranslator initializes a new AzureOpenAITranslator and returns its pointer.
 func NewAzureOpenAITranslator() *AzureOpenAITranslator {
 	return &AzureOpenAITranslator{
 		apiVersion:          defaultAPIVersion,

payload-processing/pkg/plugins/api-translation/translator/translator.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2026 The opendatahub.io Authors.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

payload-processing/pkg/plugins/api-translation/translator/vertex/vertex.go

@@ -22,15 +22,18 @@ import (
 	"regexp"
 	"strings"
 	"time"
+
+	"github.com/opendatahub-io/ai-gateway-payload-processing/pkg/plugins/api-translation/translator"
 )
 
 const (
 	vertexV1BetaPathTemplate = "/v1beta/models/%s:generateContent"
 )
 
 // compile-time interface check
-// var _ translator.Translator = &VertexTranslator{}
+var _ translator.Translator = &VertexTranslator{}
 
+// NewVertexTranslator initializes a new VertexTranslator and returns its pointer.
 func NewVertexTranslator() *VertexTranslator {
 	return &VertexTranslator{
 		modelNamePattern: regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9._-]*$`), // modelNamePattern validates Gemini model names to prevent path injection.

payload-processing/pkg/plugins/common/provider/provider.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2025.
+Copyright 2026.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.