openai: do not force API key, fix error processing

OpenAI backends will no longer require an API key to be provided. This
is because users may wish to use a service such as Portkey with its
Virtual Keys feature, which doesn't require an API key. If an API
key is not provided, an Authorization header is not sent.

Also, error handling in the openai implementation is both fixed and
expanded to support Portkey error format.

libaiac/openai/openai.go

@@ -2,7 +2,6 @@ package openai
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -26,7 +25,8 @@ type OpenAI struct {
 // Options is a struct containing all the parameters accepted by the New
 // constructor.
 type Options struct {
-	// APIKey is the OpenAI API key to use for requests. This is required.
+	// APIKey is the OpenAI API key to use for requests. Optional, but most
+	// OpenAI-compatible deployments will require it.
 	ApiKey string
 
 	// URL is the OpenAI API URL to userequests. Optional, defaults to OpenAIBackend.
@@ -53,79 +53,90 @@ func New(opts *Options) (*OpenAI, error) {
 		return nil, nil
 	}
 
-	if opts.ApiKey == "" {
-		return nil, errors.New("OpenAI backends require an API key")
-	}
-
-	// Trim "Bearer " prefix if user accidentally included it, probably by
-	// copy-pasting from somewhere.
-	opts.ApiKey = strings.TrimPrefix(opts.ApiKey, "Bearer ")
-
 	if opts.URL == "" {
 		opts.URL = OpenAIBackend
 	}
 
-	authHeaderKey := "Authorization"
-	authHeaderVal := fmt.Sprintf("Bearer %s", opts.ApiKey)
-
-	// If user provided a different authorization header, use it, and if that
-	// header is neither "Authorization" nor "Proxy-Authorization", remove the
-	// "Bearer " prefix from its value.
-	if opts.AuthHeader != "" && opts.AuthHeader != authHeaderKey {
-		authHeaderKey = opts.AuthHeader
-		if authHeaderKey != "Proxy-Authorization" {
-			authHeaderVal = opts.ApiKey
-		}
-	}
-
-	// The above section depends on the user telling us to use a different
-	// header for authorization. Previously, though, we used 'api-key' as the
-	// header if the URL was anything other than the OpenAI URL. This worked for
-	// Azure OpenAI users, but since many more providers now implement the same
-	// API (e.g. Portkey), that check was no longer correct. To maintain
-	// backwards compatibility for Azure OpenAI users, though, we can change the
-	// auth header by ourselves if the URL is *.openai.azure.com
-	if opts.AuthHeader == "" && strings.Contains(opts.URL, ".openai.azure.com") {
-		authHeaderKey = "api-key"
-		authHeaderVal = opts.ApiKey
-	}
-
 	backend := &OpenAI{
 		apiKey:     opts.ApiKey,
 		apiVersion: opts.APIVersion,
-	}
 
-	backend.HTTPClient = requests.NewClient(opts.URL).
-		Accept("application/json").
-		Header(authHeaderKey, authHeaderVal).
-		ErrorHandler(func(
-			httpStatus int,
-			contentType string,
-			body io.Reader,
-		) error {
-			var res struct {
-				Error struct {
-					Message string `json:"Message"`
-					Type    string `json:"type"`
-				} `json:"error"`
-			}
+		HTTPClient: requests.NewClient(opts.URL).
+			Accept("application/json").
+			ErrorHandler(func(
+				httpStatus int,
+				contentType string,
+				body io.Reader,
+			) error {
+				var res struct {
+					Error struct {
+						Message string `json:"message"`
+						Type    string `json:"type"`
+					} `json:"error"`
+					Message string `json:"message"`
+					Status  string `json:"status"`
+				}
+
+				err := json.NewDecoder(body).Decode(&res)
+				if err == nil {
+					if res.Error.Type != "" {
+						return fmt.Errorf(
+							"%w: [%s]: %s",
+							types.ErrRequestFailed,
+							res.Error.Type,
+							res.Error.Message,
+						)
+					} else if res.Message != "" {
+						return fmt.Errorf(
+							"%w: [%s]: %s",
+							types.ErrRequestFailed,
+							res.Status,
+							res.Message,
+						)
+					}
+				}
 
-			err := json.NewDecoder(body).Decode(&res)
-			if err != nil {
 				return fmt.Errorf(
 					"%w %s",
 					types.ErrUnexpectedStatus,
 					http.StatusText(httpStatus),
 				)
+			}),
+	}
+
+	if opts.ApiKey != "" {
+		// Trim "Bearer " prefix if user accidentally included it, probably by
+		// copy-pasting from somewhere.
+		backend.apiKey = strings.TrimPrefix(backend.apiKey, "Bearer ")
+
+		authHeaderKey := "Authorization"
+		authHeaderVal := fmt.Sprintf("Bearer %s", backend.apiKey)
+
+		// If user provided a different authorization header, use it, and if
+		// that header is neither "Authorization" nor "Proxy-Authorization",
+		// remove the "Bearer " prefix from its value.
+		if opts.AuthHeader != "" && opts.AuthHeader != authHeaderKey {
+			authHeaderKey = opts.AuthHeader
+			if authHeaderKey != "Proxy-Authorization" {
+				authHeaderVal = backend.apiKey
 			}
+		}
+
+		// The above section depends on the user telling us to use a different
+		// header for authorization. Previously, though, we used 'api-key' as
+		// the header if the URL was anything other than the OpenAI URL. This
+		// worked for Azure OpenAI users, but since many more providers now
+		// implement the same API (e.g. Portkey), that check was no longer
+		// correct. To maintain backwards compatibility for Azure OpenAI users,
+		// though, we can change the auth header by ourselves if the URL is
+		// *.openai.azure.com
+		if opts.AuthHeader == "" && strings.Contains(opts.URL, ".openai.azure.com") {
+			authHeaderKey = "api-key"
+			authHeaderVal = backend.apiKey
+		}
 
-			return fmt.Errorf(
-				"%w: [%s]: %s",
-				types.ErrRequestFailed,
-				res.Error.Type,
-				res.Error.Message,
-			)
-		})
+		backend.HTTPClient.Header(authHeaderKey, authHeaderVal)
+	}
 
 	for header, value := range opts.ExtraHeaders {
 		backend.HTTPClient.Header(header, value)