File size: 16,464 Bytes
e0aa230
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
"""

Embedding Generator Module



This module is responsible for generating vector embeddings for text chunks

using Gemini Embedding v3 with complete API integration.



Technology: Gemini Embedding v3 (gemini-embedding-exp-03-07)

"""

import logging
import os
import time
import hashlib
from datetime import datetime, timedelta
from typing import Dict, List, Any, Optional, Union
import json

# Import Gemini API and caching libraries
try:
    import google.generativeai as genai
    from cachetools import TTLCache
except ImportError as e:
    logging.warning(f"Some embedding libraries are not installed: {e}")

from utils.error_handler import EmbeddingError, error_handler, ErrorType


class EmbeddingGenerator:
    """

    Generates vector embeddings for text chunks using Gemini Embedding v3 with full functionality.



    Features:

    - Gemini Embedding v3 API integration

    - Batch processing with rate limiting

    - Intelligent retry logic with exponential backoff

    - Embedding caching mechanism

    - Cost optimization

    """

    def __init__(self, config: Optional[Dict[str, Any]] = None):
        """

        Initialize the EmbeddingGenerator with configuration.



        Args:

            config: Configuration dictionary with API parameters

        """
        self.config = config or {}
        self.logger = logging.getLogger(__name__)

        # API Configuration
        self.api_key = self.config.get("api_key", os.environ.get("GEMINI_API_KEY"))
        self.model = self.config.get("model", "gemini-embedding-exp-03-07")
        self.batch_size = self.config.get("batch_size", 5)
        self.max_retries = self.config.get("max_retries", 3)
        self.retry_delay = self.config.get("retry_delay", 1)

        # Performance settings
        self.rate_limit_delay = self.config.get("rate_limit_delay", 0.1)
        self.max_text_length = self.config.get(
            "max_text_length", 8192
        )  # ✨ 8K token limit for latest model
        self.enable_caching = self.config.get("enable_caching", True)
        self.cache_ttl = self.config.get("cache_ttl", 3600)  # 1 hour

        # Statistics tracking
        self.stats = {
            "total_requests": 0,
            "successful_requests": 0,
            "failed_requests": 0,
            "cache_hits": 0,
            "total_tokens_processed": 0,
            "start_time": datetime.now(),
        }

        # Initialize cache
        if self.enable_caching:
            self.cache = TTLCache(maxsize=1000, ttl=self.cache_ttl)
        else:
            self.cache = None

        # Validate and initialize API client
        self._initialize_client()

    def _initialize_client(self):
        """Initialize Gemini API client with validation."""
        if not self.api_key:
            self.logger.warning(
                "No Gemini API key provided. Embeddings will not be generated."
            )
            self.client = None
            return

        try:
            # Configure Gemini API
            genai.configure(api_key=self.api_key)

            # Test API connection
            self._test_api_connection()

            self.client = genai
            self.logger.info("Gemini API client initialized successfully")

        except Exception as e:
            self.logger.error(f"Failed to initialize Gemini API client: {str(e)}")
            self.client = None

    def _test_api_connection(self):
        """Test API connection with a simple request."""
        try:
            # Test with a simple embedding request
            test_result = genai.embed_content(
                model=self.model,
                content="test connection",
                task_type="retrieval_document",
            )

            if not test_result.get("embedding"):
                raise Exception("No embedding returned from test request")

            self.logger.info("API connection test successful")

        except Exception as e:
            raise EmbeddingError(f"API connection test failed: {str(e)}")

    @error_handler(ErrorType.EMBEDDING_GENERATION)
    def generate_embeddings(self, texts: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
        """

        Generate embeddings for a list of text chunks with full functionality.



        Args:

            texts: List of dictionaries containing text chunks and metadata

                Each dict should have 'content' and 'metadata' keys



        Returns:

            List of dictionaries with original content, metadata, and embeddings

        """
        if not self.client or not texts:
            self.logger.warning("No API client or empty text list")
            return texts

        self.logger.info(f"Generating embeddings for {len(texts)} text chunks")
        start_time = time.time()

        # Filter and validate texts
        valid_texts = self._validate_texts(texts)
        if not valid_texts:
            self.logger.warning("No valid texts to process")
            return texts

        # Process in batches to respect API limits
        results = []
        total_batches = (len(valid_texts) + self.batch_size - 1) // self.batch_size

        for i in range(0, len(valid_texts), self.batch_size):
            batch_num = (i // self.batch_size) + 1
            batch = valid_texts[i : i + self.batch_size]

            self.logger.info(
                f"Processing batch {batch_num}/{total_batches} ({len(batch)} items)"
            )

            try:
                batch_results = self._process_batch(batch)
                results.extend(batch_results)

                # Rate limiting between batches
                if i + self.batch_size < len(valid_texts):
                    time.sleep(self.rate_limit_delay)

            except Exception as e:
                self.logger.error(f"Batch {batch_num} failed: {str(e)}")
                # Add original items without embeddings
                for item in batch:
                    item_copy = item.copy()
                    item_copy["embedding"] = []
                    item_copy["embedding_error"] = str(e)
                    results.append(item_copy)

        # Update statistics
        processing_time = time.time() - start_time
        self.logger.info(f"Embedding generation completed in {processing_time:.2f}s")

        return results

    def _validate_texts(self, texts: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
        """

        Validate and filter text inputs.



        Args:

            texts: List of text dictionaries



        Returns:

            List of valid text dictionaries

        """
        valid_texts = []

        for i, item in enumerate(texts):
            if not isinstance(item, dict) or "content" not in item:
                self.logger.warning(f"Invalid item at index {i}: missing 'content' key")
                continue

            content = item["content"]
            if not content or not isinstance(content, str):
                self.logger.warning(
                    f"Invalid content at index {i}: empty or non-string"
                )
                continue

            # Truncate if too long
            if len(content) > self.max_text_length:
                self.logger.warning(
                    f"Truncating text at index {i}: {len(content)} -> {self.max_text_length} chars"
                )
                item = item.copy()
                item["content"] = content[: self.max_text_length]
                item["metadata"] = item.get("metadata", {})
                item["metadata"]["truncated"] = True
                item["metadata"]["original_length"] = len(content)

            valid_texts.append(item)

        return valid_texts

    def _process_batch(self, batch: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
        """

        Process a batch of text chunks to generate embeddings.



        Args:

            batch: List of dictionaries containing text chunks and metadata



        Returns:

            List of dictionaries with original content, metadata, and embeddings

        """
        # Extract content and check cache
        contents = []
        cache_results = {}

        for i, item in enumerate(batch):
            content = item["content"]

            # Check cache first
            if self.cache is not None:
                cache_key = self._get_cache_key(content)
                if cache_key in self.cache:
                    cache_results[i] = self.cache[cache_key]
                    self.stats["cache_hits"] += 1
                    continue

            contents.append((i, content))

        # Generate embeddings for non-cached content
        embeddings_map = {}
        if contents:
            content_texts = [content for _, content in contents]
            embeddings = self._generate_with_retry(content_texts)

            # Map embeddings back to indices
            for j, (original_index, content) in enumerate(contents):
                if j < len(embeddings):
                    embedding = embeddings[j]
                    embeddings_map[original_index] = embedding

                    # Cache the result
                    if self.cache is not None:
                        cache_key = self._get_cache_key(content)
                        self.cache[cache_key] = embedding

        # πŸ”— Combine results
        results = []
        for i, item in enumerate(batch):
            result = item.copy()

            # Add embedding from cache or new generation
            if i in cache_results:
                result["embedding"] = cache_results[i]
                result["embedding_source"] = "cache"
            elif i in embeddings_map:
                result["embedding"] = embeddings_map[i]
                result["embedding_source"] = "api"
            else:
                result["embedding"] = []
                result["embedding_source"] = "failed"
                self.logger.warning(f"Missing embedding for batch item {i}")

            # Add embedding metadata
            if result["embedding"]:
                result["metadata"] = result.get("metadata", {})
                result["metadata"].update(
                    {
                        "embedding_model": self.model,
                        "embedding_dimension": len(result["embedding"]),
                        "embedding_generated_at": datetime.now().isoformat(),
                    }
                )

            results.append(result)

        return results

    def _generate_with_retry(self, texts: List[str]) -> List[List[float]]:
        """

        Generate embeddings with intelligent retry logic.



        Args:

            texts: List of text strings to embed



        Returns:

            List of embedding vectors (each is a list of floats)

        """
        for attempt in range(self.max_retries):
            try:
                self.stats["total_requests"] += 1

                # Generate embeddings using Gemini API
                embeddings = []

                for text in texts:
                    try:
                        # Track tokens
                        self.stats["total_tokens_processed"] += len(text.split())

                        # Call Gemini API
                        result = self.client.embed_content(
                            model=self.model,
                            content=text,
                            task_type="retrieval_document",
                            title="Document chunk for RAG system",
                        )

                        if result and "embedding" in result:
                            embeddings.append(result["embedding"])
                        else:
                            self.logger.warning(
                                f"No embedding in API response for text: {text[:50]}..."
                            )
                            embeddings.append([])

                    except Exception as e:
                        self.logger.warning(
                            f"Failed to embed individual text: {str(e)}"
                        )
                        embeddings.append([])

                self.stats["successful_requests"] += 1
                return embeddings

            except Exception as e:
                self.stats["failed_requests"] += 1
                self.logger.warning(
                    f"Embedding generation failed (attempt {attempt+1}/{self.max_retries}): {str(e)}"
                )

                if attempt < self.max_retries - 1:
                    # Exponential backoff with jitter
                    delay = self.retry_delay * (2**attempt) + (time.time() % 1)
                    self.logger.info(f"Retrying in {delay:.1f} seconds...")
                    time.sleep(delay)

        # All retries failed
        self.logger.error("All embedding generation attempts failed")
        return [[] for _ in texts]

    @error_handler(ErrorType.EMBEDDING_GENERATION)
    def generate_query_embedding(self, query: str) -> List[float]:
        """

        Generate embedding for a single query string.



        Args:

            query: Query text to embed



        Returns:

            Embedding vector as a list of floats

        """
        if not self.client or not query:
            return []

        self.logger.info(f"Generating embedding for query: {query[:50]}...")

        # Check cache first
        if self.cache is not None:
            cache_key = self._get_cache_key(query, "query")
            if cache_key in self.cache:
                self.stats["cache_hits"] += 1
                return self.cache[cache_key]

        # Generate embedding
        embeddings = self._generate_with_retry([query])
        embedding = embeddings[0] if embeddings else []

        # Cache the result
        if embedding and self.cache is not None:
            cache_key = self._get_cache_key(query, "query")
            self.cache[cache_key] = embedding

        return embedding

    def _get_cache_key(self, text: str, prefix: str = "doc") -> str:
        """

        Generate cache key for text.



        Args:

            text: Text content

            prefix: Key prefix



        Returns:

            Cache key string

        """
        # πŸ” Create hash of text + model for unique key
        content_hash = hashlib.md5(f"{self.model}:{text}".encode()).hexdigest()
        return f"{prefix}:{content_hash}"

    def get_statistics(self) -> Dict[str, Any]:
        """

        Get embedding generation statistics.



        Returns:

            Dictionary with statistics

        """
        runtime = datetime.now() - self.stats["start_time"]

        return {
            **self.stats,
            "runtime_seconds": runtime.total_seconds(),
            "cache_hit_rate": (
                self.stats["cache_hits"] / max(1, self.stats["total_requests"]) * 100
            ),
            "success_rate": (
                self.stats["successful_requests"]
                / max(1, self.stats["total_requests"])
                * 100
            ),
            "avg_tokens_per_request": (
                self.stats["total_tokens_processed"]
                / max(1, self.stats["total_requests"])
            ),
            "cache_size": len(self.cache) if self.cache else 0,
            "model": self.model,
            "batch_size": self.batch_size,
        }

    def clear_cache(self):
        """Clear the embedding cache."""
        if self.cache:
            self.cache.clear()
            self.logger.info("Embedding cache cleared")

    def warm_up_cache(self, sample_texts: List[str]):
        """

        πŸ”₯ Warm up the cache with sample texts.



        Args:

            sample_texts: List of sample texts to pre-generate embeddings

        """
        if not sample_texts:
            return

        self.logger.info(f"πŸ”₯ Warming up cache with {len(sample_texts)} sample texts")

        sample_items = [{"content": text, "metadata": {}} for text in sample_texts]
        self.generate_embeddings(sample_items)

        self.logger.info("Cache warm-up completed")