FEATURE: Add Ollama provider (#812)

This allows our users to add the Ollama provider and use it to serve our AI bot (completion/dialect).

In this PR, we introduce:

    DiscourseAi::Completions::Dialects::Ollama which would help us translate by utilizing Completions::Endpoint::Ollama
    Correct extract_completion_from and partials_from in Endpoints::Ollama

Also

    Add tests for Endpoints::Ollama
    Introduce ollama_model fabricator

lib/completions/dialects/dialect.rb

@@ -15,6 +15,7 @@ module DiscourseAi
               DiscourseAi::Completions::Dialects::Gemini,
               DiscourseAi::Completions::Dialects::Claude,
               DiscourseAi::Completions::Dialects::Command,
+              DiscourseAi::Completions::Dialects::Ollama,
               DiscourseAi::Completions::Dialects::OpenAiCompatible,
             ]
           end

lib/completions/dialects/ollama.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Completions
+    module Dialects
+      class Ollama < Dialect
+        class << self
+          def can_translate?(model_provider)
+            model_provider == "ollama"
+          end
+        end
+
+        # TODO: Add tool suppport
+
+        def max_prompt_tokens
+          llm_model.max_prompt_tokens
+        end
+
+        private
+
+        def tokenizer
+          llm_model.tokenizer_class
+        end
+
+        def model_msg(msg)
+          { role: "assistant", content: msg[:content] }
+        end
+
+        def system_msg(msg)
+          { role: "system", content: msg[:content] }
+        end
+
+        def user_msg(msg)
+          user_message = { role: "user", content: msg[:content] }
+
+          # TODO: Add support for user messages with empbeded user ids
+          # TODO: Add support for user messages with attachments
+
+          user_message
+        end
+      end
+    end
+  end
+end

lib/completions/endpoints/ollama.rb

@@ -41,7 +41,7 @@ module DiscourseAi
           default_options
             .merge(model_params)
             .merge(messages: prompt)
-            .tap { |payload| payload[:stream] = true if @streaming_mode }
+            .tap { |payload| payload[:stream] = false if !@streaming_mode }
         end
 
         def prepare_request(payload)
@@ -51,23 +51,14 @@ module DiscourseAi
         end
 
         def partials_from(decoded_chunk)
-          decoded_chunk
-            .split("\n")
-            .map do |line|
-              data = line.split("data: ", 2)[1]
-              data == "[DONE]" ? nil : data
-            end
-            .compact
+          decoded_chunk.split("\n").compact
         end
 
         def extract_completion_from(response_raw)
-          parsed = JSON.parse(response_raw, symbolize_names: true).dig(:choices, 0)
-          # half a line sent here
+          parsed = JSON.parse(response_raw, symbolize_names: true)
           return if !parsed
 
-          response_h = @streaming_mode ? parsed.dig(:delta) : parsed.dig(:message)
-
-          response_h.dig(:content)
+          parsed.dig(:message, :content)
         end
       end
     end

spec/fabricators/llm_model_fabricator.rb

@@ -79,3 +79,12 @@ Fabricator(:samba_nova_model, from: :llm_model) do
   api_key "ABC"
   url "https://api.sambanova.ai/v1/chat/completions"
 end
+
+Fabricator(:ollama_model, from: :llm_model) do
+  display_name "Ollama llama 3.1"
+  name "llama-3.1"
+  provider "ollama"
+  api_key "ABC"
+  tokenizer "DiscourseAi::Tokenizer::Llama3Tokenizer"
+  url "http://api.ollama.ai/api/chat"
+end

spec/lib/completions/dialects/ollama_spec.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require_relative "dialect_context"
+
+RSpec.describe DiscourseAi::Completions::Dialects::Ollama do
+  fab!(:model) { Fabricate(:ollama_model) }
+  let(:context) { DialectContext.new(described_class, model) }
+
+  describe "#translate" do
+    it "translates a prompt written in our generic format to the Ollama format" do
+      ollama_version = [
+        { role: "system", content: context.system_insts },
+        { role: "user", content: context.simple_user_input },
+      ]
+
+      translated = context.system_user_scenario
+
+      expect(translated).to eq(ollama_version)
+    end
+
+    it "trims content if it's getting too long" do
+      model.max_prompt_tokens = 5000
+      translated = context.long_user_input_scenario
+
+      expect(translated.last[:role]).to eq("user")
+      expect(translated.last[:content].length).to be < context.long_message_text.length
+    end
+  end
+
+  describe "#max_prompt_tokens" do
+    it "returns the max_prompt_tokens from the llm_model" do
+      model.max_prompt_tokens = 10_000
+      expect(context.dialect(nil).max_prompt_tokens).to eq(10_000)
+    end
+  end
+end

spec/lib/completions/endpoints/ollama_spec.rb

@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+require_relative "endpoint_compliance"
+
+class OllamaMock < EndpointMock
+  def response(content)
+    message_content = { content: content }
+
+    {
+      created_at: "2024-09-25T06:47:21.283028Z",
+      model: "llama3.1",
+      message: { role: "assistant" }.merge(message_content),
+      done: true,
+      done_reason: "stop",
+      total_duration: 7_639_718_541,
+      load_duration: 299_886_663,
+      prompt_eval_count: 18,
+      prompt_eval_duration: 220_447_000,
+      eval_count: 18,
+      eval_duration: 220_447_000,
+    }
+  end
+
+  def stub_response(prompt, response_text)
+    WebMock
+      .stub_request(:post, "http://api.ollama.ai/api/chat")
+      .with(body: request_body(prompt))
+      .to_return(status: 200, body: JSON.dump(response(response_text)))
+  end
+
+  def stream_line(delta)
+    message_content = { content: delta }
+
+    +{
+      model: "llama3.1",
+      created_at: "2024-09-25T06:47:21.283028Z",
+      message: { role: "assistant" }.merge(message_content),
+      done: false,
+    }.to_json
+  end
+
+  def stub_raw(chunks)
+    WebMock.stub_request(:post, "http://api.ollama.ai/api/chat").to_return(
+      status: 200,
+      body: chunks,
+    )
+  end
+
+  def stub_streamed_response(prompt, deltas)
+    chunks = deltas.each_with_index.map { |_, index| stream_line(deltas[index]) }
+
+    chunks =
+      (
+        chunks.join("\n\n") << {
+          model: "llama3.1",
+          created_at: "2024-09-25T06:47:21.283028Z",
+          message: {
+            role: "assistant",
+            content: "",
+          },
+          done: true,
+          done_reason: "stop",
+          total_duration: 7_639_718_541,
+          load_duration: 299_886_663,
+          prompt_eval_count: 18,
+          prompt_eval_duration: 220_447_000,
+          eval_count: 18,
+          eval_duration: 220_447_000,
+        }.to_json
+      ).split("")
+
+    WebMock
+      .stub_request(:post, "http://api.ollama.ai/api/chat")
+      .with(body: request_body(prompt, stream: true))
+      .to_return(status: 200, body: chunks)
+
+    yield if block_given?
+  end
+
+  def request_body(prompt, stream: false)
+    model.default_options.merge(messages: prompt).tap { |b| b[:stream] = false if !stream }.to_json
+  end
+end
+
+RSpec.describe DiscourseAi::Completions::Endpoints::Ollama do
+  subject(:endpoint) { described_class.new(model) }
+
+  fab!(:user)
+  fab!(:model) { Fabricate(:ollama_model) }
+
+  let(:ollama_mock) { OllamaMock.new(endpoint) }
+
+  let(:compliance) do
+    EndpointsCompliance.new(self, endpoint, DiscourseAi::Completions::Dialects::Ollama, user)
+  end
+
+  describe "#perform_completion!" do
+    context "when using regular mode" do
+      it "completes a trivial prompt and logs the response" do
+        compliance.regular_mode_simple_prompt(ollama_mock)
+      end
+    end
+  end
+
+  describe "when using streaming mode" do
+    context "with simpel prompts" do
+      it "completes a trivial prompt and logs the response" do
+        compliance.streaming_mode_simple_prompt(ollama_mock)
+      end
+    end
+  end
+end