feat(ai-proxy): add streaming support and transformers

changelog/unreleased/kong/feat-ai-proxy-add-streaming.yml

@@ -0,0 +1,4 @@
+message: |
+  **AI-Proxy**: add support for streaming event-by-event responses back to client on supported providers
+scope: Plugin
+type: feature

kong/llm/drivers/anthropic.lua

@@ -229,13 +229,13 @@ function _M.subrequest(body, conf, http_opts, return_res_table)
     headers[conf.auth.header_name] = conf.auth.header_value
   end
 
-  local res, err = ai_shared.http_request(url, body_string, method, headers, http_opts)
+  local res, err, httpc = ai_shared.http_request(url, body_string, method, headers, http_opts, return_res_table)
   if err then
     return nil, nil, "request to ai service failed: " .. err
   end
 
   if return_res_table then
-    return res, res.status, nil
+    return res, res.status, nil, httpc
   else
     -- At this point, the entire request / response is complete and the connection
     -- will be closed or back on the connection pool.

kong/llm/drivers/azure.lua

@@ -59,13 +59,13 @@ function _M.subrequest(body, conf, http_opts, return_res_table)
     headers[conf.auth.header_name] = conf.auth.header_value
   end
 
-  local res, err = ai_shared.http_request(url, body_string, method, headers, http_opts)
+  local res, err, httpc = ai_shared.http_request(url, body_string, method, headers, http_opts, return_res_table)
   if err then
     return nil, nil, "request to ai service failed: " .. err
   end
 
   if return_res_table then
-    return res, res.status, nil
+    return res, res.status, nil, httpc
   else
     -- At this point, the entire request / response is complete and the connection
     -- will be closed or back on the connection pool.
@@ -82,7 +82,6 @@ end
 
 -- returns err or nil
 function _M.configure_request(conf)
-
   local parsed_url
 
   if conf.model.options.upstream_url then

kong/llm/drivers/cohere.lua

@@ -12,6 +12,104 @@ local table_new = require("table.new")
 local DRIVER_NAME = "cohere"
 --
 
+local function handle_stream_event(event_string, model_info, route_type)
+  local metadata
+
+  local event, err = cjson.decode(event_string)
+  if err then
+    return nil, "failed to decode event frame from cohere: " .. err, nil
+  end
+
+  local new_event
+
+  if event.event_type == "stream-start" then
+    kong.ctx.plugin.ai_proxy_cohere_stream_id = event.generation_id
+
+    -- ignore the rest of this one
+    new_event = {
+      choices = {
+        [1] = {
+          delta = {
+            content = "",
+            role = "assistant",
+          },
+          index = 0,
+        },
+      },
+      id = event.generation_id,
+      model = model_info.name,
+      object = "chat.completion.chunk",
+    }
+
+  elseif event.event_type == "text-generation" then
+    -- this is a token
+    if route_type == "stream/llm/v1/chat" then
+      new_event = {
+        choices = {
+          [1] = {
+            delta = {
+              content = event.text or "",
+            },
+            index = 0,
+          },
+        },
+        id = kong.ctx.plugin.ai_proxy_cohere_stream_id,
+        model = model_info.name,
+        object = "chat.completion.chunk",
+      }
+
+    elseif route_type == "stream/llm/v1/completions" then
+      new_event = {
+        choices = {
+          [1] = {
+            text = event.text or "",
+            index = 0,
+          },
+        },
+        id = kong.ctx.plugin.ai_proxy_cohere_stream_id,
+        model = model_info.name,
+        object = "text_completion",
+      }
+
+    end
+
+  elseif event.event_type == "stream-end" then
+    -- return a metadata object, with a null event
+    metadata = {
+      -- prompt_tokens = event.response.token_count.prompt_tokens,
+      -- completion_tokens = event.response.token_count.response_tokens,
+
+      completion_tokens = event.response
+                      and event.response.meta
+                      and event.response.meta.billed_units
+                      and event.response.meta.billed_units.output_tokens
+              or 
+                          event.response
+                      and event.response.token_count
+                      and event.response.token_count.response_tokens
+              or 0,
+
+      prompt_tokens = event.response
+                  and event.response.meta
+                  and event.response.meta.billed_units
+                  and event.response.meta.billed_units.input_tokens
+              or
+                      event.response
+                  and event.response.token_count
+                  and event.token_count.prompt_tokens
+              or 0,
+    }
+
+  end
+
+  if new_event then
+    new_event = cjson.encode(new_event)
+    return new_event, nil, metadata
+  else
+    return nil, nil, metadata  -- caller code will handle "unrecognised" event types
+  end
+end
+
 local transformers_to = {
   ["llm/v1/chat"] = function(request_table, model)
     request_table.model = model.name
@@ -243,6 +341,9 @@ local transformers_from = {
 
     return cjson.encode(prompt)
   end,
+
+  ["stream/llm/v1/chat"] = handle_stream_event,
+  ["stream/llm/v1/completions"] = handle_stream_event,
 }
 
 function _M.from_format(response_string, model_info, route_type)
@@ -253,7 +354,7 @@ function _M.from_format(response_string, model_info, route_type)
     return nil, fmt("no transformer available from format %s://%s", model_info.provider, route_type)
   end
 
-  local ok, response_string, err = pcall(transformers_from[route_type], response_string, model_info)
+  local ok, response_string, err, metadata = pcall(transformers_from[route_type], response_string, model_info, route_type)
   if not ok or err then
     return nil, fmt("transformation failed from type %s://%s: %s",
                     model_info.provider,
@@ -262,7 +363,7 @@ function _M.from_format(response_string, model_info, route_type)
                   )
   end
 
-  return response_string, nil
+  return response_string, nil, metadata
 end
 
 function _M.to_format(request_table, model_info, route_type)
@@ -344,13 +445,13 @@ function _M.subrequest(body, conf, http_opts, return_res_table)
     headers[conf.auth.header_name] = conf.auth.header_value
   end
 
-  local res, err = ai_shared.http_request(url, body_string, method, headers, http_opts)
+  local res, err, httpc = ai_shared.http_request(url, body_string, method, headers, http_opts, return_res_table)
   if err then
     return nil, nil, "request to ai service failed: " .. err
   end
 
   if return_res_table then
-    return res, res.status, nil
+    return res, res.status, nil, httpc
   else
     -- At this point, the entire request / response is complete and the connection
     -- will be closed or back on the connection pool.

kong/llm/drivers/llama2.lua

@@ -133,6 +133,8 @@ local transformers_from = {
   ["llm/v1/completions/raw"] = from_raw,
   ["llm/v1/chat/ollama"] = ai_shared.from_ollama,
   ["llm/v1/completions/ollama"] = ai_shared.from_ollama,
+  ["stream/llm/v1/chat/ollama"] = ai_shared.from_ollama,
+  ["stream/llm/v1/completions/ollama"] = ai_shared.from_ollama,
 }
 
 local transformers_to = {
@@ -155,8 +157,8 @@ function _M.from_format(response_string, model_info, route_type)
   if not transformers_from[transformer_type] then
     return nil, fmt("no transformer available from format %s://%s", model_info.provider, transformer_type)
   end
-  
-  local ok, response_string, err = pcall(
+
+  local ok, response_string, err, metadata = pcall(
     transformers_from[transformer_type],
     response_string,
     model_info,
@@ -166,7 +168,7 @@ function _M.from_format(response_string, model_info, route_type)
     return nil, fmt("transformation failed from type %s://%s: %s", model_info.provider, route_type, err or "unexpected_error")
   end
 
-  return response_string, nil
+  return response_string, nil, metadata
 end
 
 function _M.to_format(request_table, model_info, route_type)
@@ -217,13 +219,13 @@ function _M.subrequest(body, conf, http_opts, return_res_table)
     headers[conf.auth.header_name] = conf.auth.header_value
   end
 
-  local res, err = ai_shared.http_request(url, body_string, method, headers, http_opts)
+  local res, err, httpc = ai_shared.http_request(url, body_string, method, headers, http_opts, return_res_table)
   if err then
     return nil, nil, "request to ai service failed: " .. err
   end
 
   if return_res_table then
-    return res, res.status, nil
+    return res, res.status, nil, httpc
   else
     -- At this point, the entire request / response is complete and the connection
     -- will be closed or back on the connection pool.
@@ -265,7 +267,7 @@ function _M.configure_request(conf)
 
   kong.service.request.set_path(parsed_url.path)
   kong.service.request.set_scheme(parsed_url.scheme)
-  kong.service.set_target(parsed_url.host, tonumber(parsed_url.port))
+  kong.service.set_target(parsed_url.host, (tonumber(parsed_url.port) or 443))
 
   local auth_header_name = conf.auth and conf.auth.header_name
   local auth_header_value = conf.auth and conf.auth.header_value

kong/llm/drivers/mistral.lua

@@ -17,6 +17,8 @@ local DRIVER_NAME = "mistral"
 local transformers_from = {
   ["llm/v1/chat/ollama"] = ai_shared.from_ollama,
   ["llm/v1/completions/ollama"] = ai_shared.from_ollama,
+  ["stream/llm/v1/chat/ollama"] = ai_shared.from_ollama,
+  ["stream/llm/v1/completions/ollama"] = ai_shared.from_ollama,
 }
 
 local transformers_to = {
@@ -104,13 +106,13 @@ function _M.subrequest(body, conf, http_opts, return_res_table)
     headers[conf.auth.header_name] = conf.auth.header_value
   end
 
-  local res, err = ai_shared.http_request(url, body_string, method, headers, http_opts)
+  local res, err, httpc = ai_shared.http_request(url, body_string, method, headers, http_opts, return_res_table)
   if err then
     return nil, nil, "request to ai service failed: " .. err
   end
 
   if return_res_table then
-    return res, res.status, nil
+    return res, res.status, nil, httpc
   else
     -- At this point, the entire request / response is complete and the connection
     -- will be closed or back on the connection pool.

kong/llm/drivers/openai.lua

@@ -11,6 +11,18 @@ local socket_url = require "socket.url"
 local DRIVER_NAME = "openai"
 --
 
+local function handle_stream_event(event_string)
+  if #event_string > 0 then
+    local lbl, val = event_string:match("(%w*): (.*)")
+
+    if lbl == "data" then
+      return val
+    end
+  end
+
+  return nil
+end
+
 local transformers_to = {
   ["llm/v1/chat"] = function(request_table, model, max_tokens, temperature, top_p)
     -- if user passed a prompt as a chat, transform it to a chat message
@@ -29,8 +41,9 @@ local transformers_to = {
       max_tokens = max_tokens,
       temperature = temperature,
       top_p = top_p,
+      stream = request_table.stream or false,
     }
-  
+
     return this, "application/json", nil
   end,
 
@@ -40,6 +53,7 @@ local transformers_to = {
       model = model,
       max_tokens = max_tokens,
       temperature = temperature,
+      stream = request_table.stream or false,
     }
 
     return this, "application/json", nil
@@ -72,6 +86,9 @@ local transformers_from = {
       return nil, "'choices' not in llm/v1/completions response"
     end
   end,
+
+  ["stream/llm/v1/chat"] = handle_stream_event,
+  ["stream/llm/v1/completions"] = handle_stream_event,
 }
 
 function _M.from_format(response_string, model_info, route_type)
@@ -155,13 +172,13 @@ function _M.subrequest(body, conf, http_opts, return_res_table)
     headers[conf.auth.header_name] = conf.auth.header_value
   end
 
-  local res, err = ai_shared.http_request(url, body_string, method, headers, http_opts)
+  local res, err, httpc = ai_shared.http_request(url, body_string, method, headers, http_opts, return_res_table)
   if err then
     return nil, nil, "request to ai service failed: " .. err
   end
 
   if return_res_table then
-    return res, res.status, nil
+    return res, res.status, nil, httpc
   else
     -- At this point, the entire request / response is complete and the connection
     -- will be closed or back on the connection pool.