greycloud 0.3.8

Reusable Google GenAI/Vertex AI Client Module

GreyCloud

A comprehensive, configurable Python package for interacting with Google's Vertex AI and GenAI services (Gemini), including authentication, content generation, batch processing, token counting, and file management.

GreyCloud wraps the lower-level google-genai client with:

• Unified authentication (API key or OAuth + optional service account impersonation)
• Resilient content generation with automatic retry and re-authentication
• Config-driven client setup via a single GreyCloudConfig dataclass
• Context caching for 75-90% cost savings on repeated queries
• Optional Vertex AI Search tools for retrieval-augmented generation
• Batch helpers for large offline jobs and GCS integration

---

1. What GreyCloud Does

GreyCloud provides four main building blocks:

• GreyCloudConfig – configuration object populated from environment variables or code
• GreyCloudClient – high-level client for content generation, streaming, token counting, and retries
• GreyCloudCache – context caching for cost-efficient repeated queries on the same content
• GreyCloudBatch – helper for batch jobs and GCS-backed workflows

High-level capabilities:

• Content generation (streaming and non-streaming) with per-request overrides
• Automatic retry with exponential backoff and authentication-aware recovery
• Context caching with 75-90% cost savings on cached input tokens
• Token counting with graceful approximation fallback
• Vertex AI Search integration via a simple flag and datastore string
• Batch processing to upload files, create jobs, monitor, and download results

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2. Why Use GreyCloud Instead of google-genai Directly?

Using google-genai directly is flexible but verbose. GreyCloud focuses on developer ergonomics and resilience:

• Unified auth helper

  • One function (create_client / GreyCloudClient) that:
    • Uses Application Default Credentials when available
    • Optionally impersonates a service account when sa_email is set
    • Falls back to gcloud auth print-access-token when needed
    • Supports API key authentication via a simple config flag
  • Clear error messages that point to:
    • gcloud auth application-default login
    • IAM role requirements for impersonation

• Config normalization

  • A single dataclass (GreyCloudConfig) encapsulates:
    • Project, location, endpoint, model
    • Auth choices (API key vs OAuth + SA impersonation)
    • Generation parameters (temperature, top_p, max_output_tokens, seed)
    • Safety settings
    • Thinking configuration
    • Vertex AI Search datastore
    • Batch/GCS bucket settings

• Resilient generation

  • GreyCloudClient.generate_with_retry(...):
    • Detects auth-related vs transient errors
    • Performs exponential backoff with jitter
    • Attempts re-authentication when appropriate (for OAuth-based flows)
    • Re-creates the underlying genai.Client as needed

• Tools & Search wiring

  • Vertex AI Search is turned on with:
    • use_vertex_ai_search=True
    • vertex_ai_search_datastore="projects/.../dataStores/...".
  • GreyCloud constructs the appropriate types.Tool and wires it into calls.

• Batch utilities

  • GreyCloudBatch wraps the more verbose raw batch APIs:
    • Handles JSONL creation
    • Manages GCS paths and result locations
    • Tries multiple model naming formats (publishers/google/models/... vs short name)

• Sync vs async

  • Same config (GreyCloudConfig) and same method names for sync and async.

  • Use GreyCloudClient for synchronous code; use GreyCloudAsyncClient for async/rate-limited usage.

  • The async client applies RPM, TPM, and concurrency limits via VertexRateLimiter; use it when you need to stay within quotas (e.g. in web backends).

  • API mapping:

    Sync (GreyCloudClient)	Async (GreyCloudAsyncClient)
    generate_content(...)	await generate_content(...)
    generate_content_stream(...)	async for x in generate_content_stream(...)
    generate_with_retry(..., streaming=False)	await generate_with_retry(...)
    generate_with_retry(..., streaming=True)	async for x in (await generate_with_retry(..., streaming=True))
    count_tokens(...)	await count_tokens(...)

  • For advanced use the underlying genai.Client is available as .client on both clients; rate-limited generation should go through the client’s methods, not raw client.aio.models.*.

---

3. Installation

Basic Installation

pip install greycloud

Development Installation

git clone https://github.com/jbff/greycloud.git
cd greycloud
pip install -e ".[dev]"

4. Quick Start: Basic Client and Single Call

from greycloud import GreyCloudConfig, GreyCloudClient
from google.genai import types

# Create configuration (override defaults as needed)
config = GreyCloudConfig(
    project_id="your-project-id",
    location="us-central1",
    # Default model is a Gemini 3 flash model; you can override if desired.
    model="gemini-3-flash-preview",
)

# Create client
client = GreyCloudClient(config)

# Generate content
contents = [
    types.Content(
        role="user",
        parts=[types.Part.from_text(text="Hello, how are you?")]
    )
]

response = client.generate_content(contents)
print(response.text)

---

5. Detailed Examples

5.1 Creating a Client from Environment Only

Environment:

export PROJECT_ID="your-project-id"
export LOCATION="us-central1"

Code:

from greycloud import GreyCloudClient
from google.genai import types

client = GreyCloudClient()  # GreyCloudConfig is created from env

contents = [
    types.Content(
        role="user",
        parts=[types.Part.from_text(text="Summarize the benefits of Vertex AI.")]
    )
]

response = client.generate_content(contents)
print(response.text)

5.2 Per-Request Overrides

response = client.generate_content(
    contents,
    temperature=0.7,
    max_output_tokens=1024,
    system_instruction="You are a concise technical assistant.",
)

5.3 Streaming Generation

By default, streaming yields plain text strings representing the generated content chunks:

for chunk in client.generate_content_stream(contents):
    print(chunk, end="", flush=True)

If you need access to candidate metadata, usage metrics, or safety ratings, you can pass return_chunks=True to yield the raw GenerateContentResponse chunk objects instead of strings:

for chunk in client.generate_content_stream(contents, return_chunks=True):
    # chunk is a google.genai.types.GenerateContentResponse object
    print(chunk.text, end="", flush=True)

5.4 Automatic Retry & Auth Recovery

from google.genai import types

contents = [
    types.Content(
        role="user",
        parts=[types.Part.from_text(text="Give me a short creative story about a robot therapist.")]
    )
]

response = client.generate_with_retry(
    contents,
    max_retries=5,
    streaming=False,
)

print(response.text)

For streaming with retry:

for chunk in client.generate_with_retry(
    contents,
    max_retries=5,
    streaming=True,
):
    print(chunk, end="", flush=True)

To stream raw response chunk objects with retry logic, pass return_chunks=True:

for chunk in client.generate_with_retry(
    contents,
    max_retries=5,
    streaming=True,
    return_chunks=True,
):
    print(chunk.text, end="", flush=True)

5.5 Token Counting with Fallback

from google.genai import types

contents = [
    types.Content(
        role="user",
        parts=[types.Part.from_text(text="Count the tokens in this example message.")]
    )
]

token_count = client.count_tokens(
    contents,
    system_instruction="You are a helpful assistant.",
)

print(f"Total tokens: {token_count}")

If the underlying API is unavailable, GreyCloud falls back to an approximate character-based count.

5.6 Context Caching for Cost Savings

Context caching allows you to cache large content (documents, code, media) and reuse it across multiple requests without re-sending tokens each time. This provides significant cost savings:

• Cached token discount: 75-90% off input token costs (depending on model)
• Storage cost: $1.00 per million tokens per hour (prorated by minute)

from greycloud import GreyCloudConfig, GreyCloudCache

config = GreyCloudConfig(project_id="your-project-id")
cache_client = GreyCloudCache(config)

# Cache a large document (must meet minimum token threshold: 1,024-4,096 tokens)
large_document = "..." # Your large content here

cache = cache_client.create_cache_from_text(
    text=large_document,
    display_name="my-document-cache",
    system_instruction="You are a helpful document analyst.",
    ttl_seconds=3600,  # 1 hour
)

print(f"Cache created: {cache.name}")
print(f"Cached tokens: {cache.usage_metadata.total_token_count}")

# Query the cache multiple times (each query uses cached tokens at discounted rate)
questions = [
    "Summarize the main points",
    "What are the key findings?",
    "List any recommendations",
]

for question in questions:
    response = cache_client.generate_with_cache(
        cache_name=cache.name,
        prompt=question,
    )
    print(f"Q: {question}")
    print(f"A: {response.text}\n")

# IMPORTANT: Delete cache when done to stop storage charges
cache_client.delete_cache(cache.name)

You can also cache GCS files:

cache = cache_client.create_cache_from_files(
    file_uris=[
        "gs://your-bucket/document1.pdf",
        "gs://your-bucket/document2.txt",
    ],
    display_name="multi-file-cache",
    ttl_seconds=7200,  # 2 hours
)

Cache management:

# List all caches
for cached_content in cache_client.list_caches():
    info = cache_client.get_cache_info(cached_content)
    print(f"{info['name']}: {info.get('total_token_count', 'N/A')} tokens")

# Extend cache TTL before it expires
cache_client.update_cache_ttl(cache.name, ttl_seconds=7200)

# Delete all caches with a specific display name
cache_client.delete_all_caches(display_name_filter="my-document-cache")

Note: Context caching is a paid feature and not available in the free tier.

5.7 Using Cached Content with GreyCloudClient

You can also use cached content directly with GreyCloudClient by passing the cached_content parameter:

from greycloud import GreyCloudConfig, GreyCloudClient, GreyCloudCache
from google.genai import types

config = GreyCloudConfig(project_id="your-project-id")

# Create cache
cache_client = GreyCloudCache(config)
cache = cache_client.create_cache_from_text(
    text=large_document,
    display_name="my-cache",
    ttl_seconds=3600,
)

# Use with GreyCloudClient
client = GreyCloudClient(config)

contents = [
    types.Content(
        role="user",
        parts=[types.Part.from_text(text="Summarize the document")]
    )
]

response = client.generate_content(
    contents,
    cached_content=cache.name,  # Use the cache
)

# Streaming also works with cached content
for chunk in client.generate_content_stream(
    contents,
    cached_content=cache.name,
):
    print(chunk, end="", flush=True)

# Clean up
cache_client.delete_cache(cache.name)

5.8 Vertex AI Search as a Tool

from greycloud import GreyCloudConfig, GreyCloudClient
from google.genai import types

config = GreyCloudConfig(
    project_id="your-project-id",
    location="us-central1",
    use_vertex_ai_search=True,
    vertex_ai_search_datastore=(
        "projects/PROJECT_ID/locations/LOCATION/"
        "collections/default_collection/dataStores/DATASTORE_ID"
    ),
)

client = GreyCloudClient(config)

contents = [
    types.Content(
        role="user",
        parts=[types.Part.from_text(text="Using the knowledge base, explain the diagnostic steps for adult ASD.")]
    )
]

response = client.generate_content(contents)
print(response.text)

5.9 Batch Processing with GCS

Batch jobs use a GCS bucket for request input and result output. Set batch_gcs_bucket (and optionally gcs_bucket for general uploads). The batch API expects JSONL input following the Vertex AI REST GenerateContentRequest schema: one line per request, each line a JSON object with a request key containing model, contents, and optional generationConfig, systemInstruction, and safetySettings (all camelCase). Note: InlinedRequest.metadata is not forwarded to batch JSONL because Vertex rejects numeric string values in proto label fields — use prompt-embedded ID tags (e.g. [SLICE_ID:...]) for request matching. Results are written by Vertex to predictions.jsonl under the job's destination prefix; download_batch_results finds and downloads that file.

from greycloud import GreyCloudConfig, GreyCloudBatch
from google.genai import types
import json

config = GreyCloudConfig(
    project_id="your-project-id",
    batch_gcs_bucket="your-project-batch-jobs",  # Must exist; used for batch I/O
)

batch = GreyCloudBatch(config)

# Upload a couple of JSON docs (use same bucket via bucket_name)
files = [
    {"name": "data1.json", "content": json.dumps({"key": "value"})},
    {"name": "data2.json", "content": json.dumps({"key2": "value2"})},
]

file_uris = batch.upload_files_to_gcs(files, bucket_name=config.batch_gcs_bucket)

batch_requests = []
for filename, gcs_uri in file_uris.items():
    batch_requests.append(
        types.InlinedRequest(
            model=config.model,
            contents=[
                {
                    "role": "user",
                    "parts": [
                        {"text": f"Analyze {filename}: "},
                        {"file_data": {"file_uri": gcs_uri, "mime_type": "application/json"}},
                    ],
                }
            ],
            config=types.GenerateContentConfig(
                temperature=0.2,
                max_output_tokens=65535,
            ),
        )
    )

batch_job = batch.create_batch_job(batch_requests)
batch_job = batch.monitor_batch_job(batch_job)

output_file = batch.download_batch_results(batch_job, "results.jsonl")
print(f"Batch results saved to: {output_file}")

5.10 Custom Auth (Advanced)

from greycloud.auth import create_client

client = create_client(
    project_id="your-project-id",
    location="us-central1",
    sa_email="[e-mail]",  # Optional
    use_api_key=False,
)

---

Documentation

All usage and configuration details are documented in this README.md. For additional examples, see:

• examples/simple.py – minimal content-generation script.
• examples/caching.py – context caching for cost-efficient repeated queries.

Requirements

• Python 3.10+
• Google Cloud Project with Vertex AI enabled
• google-genai package (installed with greycloud)
• google-auth package (installed with greycloud, for OAuth)
• google-cloud-storage package (installed with greycloud; only needed if you use batch/GCS helpers)

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Testing

Run the test suite:

pytest

Run with coverage:

pytest --cov=greycloud --cov-report=html

License

MIT License (see LICENSE file).

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.