Add Ollama embeddings support (langchain-ai#2520)

* ✨ Add Ollama Embeddings Class

* ✅ Add simple tests and refactor a bit

* fix inheritance

* authored by @smndtrl: Add ollama embeddings to configs

* ♻️ change sorting of class members

* 🎨 implement changes suggested by @jacoblee93

* refactor constructor to allow for no arguments

* consistancy fix

* Add first draft of documentation

* fix broken link in doc

docs/extras/modules/data_connection/text_embedding/integrations/ollama.mdx

@@ -0,0 +1,56 @@
+# Ollama
+
+The `OllamaEmbeddings` class uses the `/api/embeddings` route of a locally hosted [Ollama](https://ollama.ai) server to generate embeddings for given texts.
+
+# Setup
+
+Follow [these instructions](https://github.com/jmorganca/ollama) to set up and run a local Ollama instance.
+
+# Usage
+
+Basic usage:
+
+```typescript
+import { OllamaEmbeddings } from "langchain/embeddings/ollama";
+
+const embeddings = new OllamaEmbeddings({
+  model: "llama2", // default value
+  baseUrl: "http://localhost:11434", // default value
+});
+```
+
+Ollama [model parameters](https://github.com/jmorganca/ollama/blob/main/docs/modelfile.md#valid-parameters-and-values) are also supported:
+
+```typescript
+import { OllamaEmbeddings } from "langchain/embeddings/ollama";
+
+const embeddings = new OllamaEmbeddings({
+  model: "llama2", // default value
+  baseUrl: "http://localhost:11434", // default value
+  requestOptions: {
+    useMMap: true, // use_mmap 1
+    numThreads: 6, // num_thread 6
+    numGpu: 1, // num_gpu 1
+  },
+});
+```
+
+# Example usage:
+
+```typescript
+import { OllamaEmbeddings } from "langchain/embeddings/ollama";
+
+const embeddings = new OllamaEmbeddings({
+  model: "llama2", // default value
+  baseUrl: "http://localhost:11434", // default value
+  requestOptions: {
+    useMMap: true,
+    numThreads: 6,
+    numGpu: 1,
+  },
+});
+
+const documents = ["Hello World!", "Bye Bye"];
+
+const documentEmbeddings = await embeddings.embedDocuments(documents);
+```

langchain/.gitignore

@@ -70,6 +70,9 @@ embeddings/cache_backed.d.ts
 embeddings/fake.cjs
 embeddings/fake.js
 embeddings/fake.d.ts
+embeddings/ollama.cjs
+embeddings/ollama.js
+embeddings/ollama.d.ts
 embeddings/openai.cjs
 embeddings/openai.js
 embeddings/openai.d.ts

langchain/package.json

@@ -82,6 +82,9 @@
     "embeddings/fake.cjs",
     "embeddings/fake.js",
     "embeddings/fake.d.ts",
+    "embeddings/ollama.cjs",
+    "embeddings/ollama.js",
+    "embeddings/ollama.d.ts",
     "embeddings/openai.cjs",
     "embeddings/openai.js",
     "embeddings/openai.d.ts",
@@ -1229,6 +1232,11 @@
       "import": "./embeddings/fake.js",
       "require": "./embeddings/fake.cjs"
     },
+    "./embeddings/ollama": {
+      "types": "./embeddings/ollama.d.ts",
+      "import": "./embeddings/ollama.js",
+      "require": "./embeddings/ollama.cjs"
+    },
     "./embeddings/openai": {
       "types": "./embeddings/openai.d.ts",
       "import": "./embeddings/openai.js",

langchain/scripts/create-entrypoints.js

@@ -37,6 +37,7 @@ const entrypoints = {
   "embeddings/base": "embeddings/base",
   "embeddings/cache_backed": "embeddings/cache_backed",
   "embeddings/fake": "embeddings/fake",
+  "embeddings/ollama": "embeddings/ollama",
   "embeddings/openai": "embeddings/openai",
   "embeddings/cohere": "embeddings/cohere",
   "embeddings/tensorflow": "embeddings/tensorflow",
@@ -225,7 +226,7 @@ const entrypoints = {
   "storage/in_memory": "storage/in_memory",
   "storage/ioredis": "storage/ioredis",
   // hub
-  "hub": "hub",
+  hub: "hub",
   // utilities
   "util/math": "util/math",
   // experimental
@@ -235,7 +236,8 @@ const entrypoints = {
   "experimental/plan_and_execute": "experimental/plan_and_execute/index",
   "experimental/multimodal_embeddings/googlevertexai":
     "experimental/multimodal_embeddings/googlevertexai",
-  "experimental/chat_models/anthropic_functions": "experimental/chat_models/anthropic_functions",
+  "experimental/chat_models/anthropic_functions":
+    "experimental/chat_models/anthropic_functions",
   // evaluation
   evaluation: "evaluation/index",
 };

langchain/src/embeddings/ollama.ts

@@ -0,0 +1,135 @@
+import { OllamaInput, OllamaRequestParams } from "../util/ollama.js";
+import { Embeddings, EmbeddingsParams } from "./base.js";
+
+type CamelCasedRequestOptions = Omit<OllamaInput, "baseUrl" | "model">;
+
+/**
+ * Interface for OllamaEmbeddings parameters. Extends EmbeddingsParams and
+ * defines additional parameters specific to the OllamaEmbeddings class.
+ */
+interface OllamaEmbeddingsParams extends EmbeddingsParams {
+  /** The Ollama model to use, e.g: "llama2:13b" */
+  model?: string;
+
+  /** Base URL of the Ollama server, defaults to "http://localhost:11434" */
+  baseUrl?: string;
+
+  /** Advanced Ollama API request parameters in camelCase, see
+   * https://github.com/jmorganca/ollama/blob/main/docs/modelfile.md#valid-parameters-and-values
+   * for details of the available parameters.
+   */
+  requestOptions?: CamelCasedRequestOptions;
+}
+
+export class OllamaEmbeddings extends Embeddings {
+  model = "llama2";
+
+  baseUrl = "http://localhost:11434";
+
+  requestOptions?: OllamaRequestParams["options"];
+
+  constructor(params?: OllamaEmbeddingsParams) {
+    super(params || {});
+
+    if (params?.model) {
+      this.model = params.model;
+    }
+
+    if (params?.baseUrl) {
+      this.baseUrl = params.baseUrl;
+    }
+
+    if (params?.requestOptions) {
+      this.requestOptions = this._convertOptions(params.requestOptions);
+    }
+  }
+
+  /** convert camelCased Ollama request options like "useMMap" to
+   * the snake_cased equivalent which the ollama API actually uses.
+   * Used only for consistency with the llms/Ollama and chatModels/Ollama classes
+   */
+  _convertOptions(requestOptions: CamelCasedRequestOptions) {
+    const snakeCasedOptions: Record<string, unknown> = {};
+    const mapping: Record<keyof CamelCasedRequestOptions, string> = {
+      embeddingOnly: "embedding_only",
+      f16KV: "f16_kv",
+      frequencyPenalty: "frequency_penalty",
+      logitsAll: "logits_all",
+      lowVram: "low_vram",
+      mainGpu: "main_gpu",
+      mirostat: "mirostat",
+      mirostatEta: "mirostat_eta",
+      mirostatTau: "mirostat_tau",
+      numBatch: "num_batch",
+      numCtx: "num_ctx",
+      numGpu: "num_gpu",
+      numGqa: "num_gqa",
+      numKeep: "num_keep",
+      numThread: "num_thread",
+      penalizeNewline: "penalize_newline",
+      presencePenalty: "presence_penalty",
+      repeatLastN: "repeat_last_n",
+      repeatPenalty: "repeat_penalty",
+      ropeFrequencyBase: "rope_frequency_base",
+      ropeFrequencyScale: "rope_frequency_scale",
+      temperature: "temperature",
+      stop: "stop",
+      tfsZ: "tfs_z",
+      topK: "top_k",
+      topP: "top_p",
+      typicalP: "typical_p",
+      useMLock: "use_mlock",
+      useMMap: "use_mmap",
+      vocabOnly: "vocab_only",
+    };
+
+    for (const [key, value] of Object.entries(requestOptions)) {
+      const snakeCasedOption = mapping[key as keyof CamelCasedRequestOptions];
+      if (snakeCasedOption) {
+        snakeCasedOptions[snakeCasedOption] = value;
+      }
+    }
+    return snakeCasedOptions;
+  }
+
+  async _request(prompt: string): Promise<number[]> {
+    const { model, baseUrl, requestOptions } = this;
+
+    const response = await fetch(`${baseUrl}/api/embeddings`, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({
+        prompt,
+        model,
+        options: requestOptions,
+      }),
+    });
+    if (!response.ok) {
+      throw new Error(
+        `Request to Ollama server failed: ${response.status} ${response.statusText}`
+      );
+    }
+
+    const json = await response.json();
+    return json.embedding;
+  }
+
+  async _embed(strings: string[]): Promise<number[][]> {
+    const embeddings: number[][] = [];
+
+    for await (const prompt of strings) {
+      const embedding = await this.caller.call(() => this._request(prompt));
+      embeddings.push(embedding);
+    }
+
+    return embeddings;
+  }
+
+  async embedDocuments(documents: string[]) {
+    return this._embed(documents);
+  }
+
+  async embedQuery(document: string) {
+    return (await this.embedDocuments([document]))[0];
+  }
+}

langchain/src/embeddings/tests/ollama.int.test.ts

@@ -0,0 +1,16 @@
+import { test, expect } from "@jest/globals";
+import { OllamaEmbeddings } from "../ollama.js";
+
+test("Test OllamaEmbeddings.embedQuery", async () => {
+  const embeddings = new OllamaEmbeddings();
+  const res = await embeddings.embedQuery("Hello world");
+  expect(typeof res[0]).toBe("number");
+});
+
+test("Test OllamaEmbeddings.embedDocuments", async () => {
+  const embeddings = new OllamaEmbeddings();
+  const res = await embeddings.embedDocuments(["Hello world", "Bye bye"]);
+  expect(res).toHaveLength(2);
+  expect(typeof res[0][0]).toBe("number");
+  expect(typeof res[1][0]).toBe("number");
+});

langchain/src/load/import_map.ts

@@ -10,6 +10,7 @@ export * as chains__openai_functions from "../chains/openai_functions/index.js";
 export * as embeddings__base from "../embeddings/base.js";
 export * as embeddings__cache_backed from "../embeddings/cache_backed.js";
 export * as embeddings__fake from "../embeddings/fake.js";
+export * as embeddings__ollama from "../embeddings/ollama.js";
 export * as embeddings__openai from "../embeddings/openai.js";
 export * as embeddings__minimax from "../embeddings/minimax.js";
 export * as llms__base from "../llms/base.js";

langchain/tsconfig.json

@@ -4,11 +4,7 @@
     "outDir": "../dist",
     "rootDir": "./src",
     "target": "ES2021",
-    "lib": [
-      "ES2021",
-      "ES2022.Object",
-      "DOM"
-    ],
+    "lib": ["ES2021", "ES2022.Object", "DOM"],
     "module": "ES2020",
     "moduleResolution": "nodenext",
     "esModuleInterop": true,
@@ -22,14 +18,8 @@
     "allowJs": true,
     "strict": true
   },
-  "include": [
-    "src/**/*"
-  ],
-  "exclude": [
-    "node_modules",
-    "dist",
-    "docs"
-  ],
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "docs"],
   "typedocOptions": {
     "entryPoints": [
       "src/load/index.ts",
@@ -55,6 +45,7 @@
       "src/embeddings/base.ts",
       "src/embeddings/cache_backed.ts",
       "src/embeddings/fake.ts",
+      "src/embeddings/ollama.ts",
       "src/embeddings/openai.ts",
       "src/embeddings/cohere.ts",
       "src/embeddings/tensorflow.ts",