Financing digital transformation poses a significant problem for many enterprises we work with. It’s not because the C-suite doesn’t support it: the need to become more agile, digital, and data-driven is nearly ubiquitous in executive public pronouncements. But most large organizations look at IT investment in a way that’s ineffective for a successful digital transformation effort.  

A varied combination of  factors affect an organization’s success in the digital ecosystem, and a lack of alignment between IT and business leaders can hamper even the most digitally sophisticated organizations. Empirical research by the Apigee Institute shows clear evidence that a solid digital transformation effort, aligned across business and marketing, whose progress is carefully tied to core enterprise metrics, must be supported by an investment strategy that uses a “real options” portfolio approach.

Let’s explore ways to think about funding digital transformation.

Planning for the Unimaginable

Common IT investment strategies are focused on straight-line net present value (NPV) business case calculations, which emphasize linear solutions and impacts. These methods ignore the value of enabling a range of options and potential future use cases, which an API program, with its reusable, highly consumable digital assets, makes available for the enterprise. In addition, these methods often ignore the value of the new categories of business data generated by such programs, as well as business capabilities that were impossible to imagine before the capabilities came online.

One media company we’re working with was astounded by a project that now makes key sales provisioning available to large distribution partners within two months, when previous estimates predicted two years and many millions of dollars, each.

More importantly, that functionality will now be reused across all of their numerous current partners and sales channels, and is enabling exciting new partnerships that were too costly before. This functionality was an unexpected by-product of their original API effort—it wasn’t even the main focus of the initial project.  

There was no way that the impact of this capability or its implications on new business could have been predicted at the outset, and no way to formally model the outsized impact this functionality will have on the enterprise. Any attempts to do so would have been deemed ludicrous.

Breaking from the Status Quo

So how do you fund an API-driven digital transformation, which by nature emphasizes speed and optionality to unlock new ways of doing business, instead of the business-as-usual single-use, point-to-point integrations that perpetuate status quo thinking? For a world where the latter is the dominant paradigm and you don’t have a clear C-level mandate, here are three suggestions.

1.  Enable your web/e-commerce teams. Many such teams find their responsibilities expanded to include mobile, kiosk, and many other digital initiatives, while being trapped in the traditional web server, do-it-yourself paradigm. These teams are actually quite open to technology, and often harbour weekend hackers who love to explore the new capabilities that are expanding the digital ecosystem at light speed. Tapping this passion by funding new approaches and quickly realizing immediate projects can create first the technical, and then the business proof points that resonate with a strategy team. These capabilities must be nurtured to move out of the lab into production, where real results are created.  

2. Focus on partnerships. Opening and accelerating  your relationships with partners via APIs (read more about partner API initiatives here) is high-impact and relatively easy to model. This business area can prove out an API platform, and in our experience creates clear business value that can support future justifications for other business units. What’s best about these wins is that sales operations groups are typically very tactical and demanding, so when they see the value, these groups will send a message to the rest of the organization that APIs have business value. Further, your enterprise’s core partnerships have the focus of executive attention. Adding value here will elevate the stature of the API program in the C-suite.

3. Work on your CFO/financial organization. Using your successes in e-commerce and partnerships, you can propose a more robust investment using a real options approach that leads to treatment of APIs as products. This path is predicated on what research has proven to work: the adoption of a digital KPI target, coupled with a portfolio of programs whose net result is to achieve the target KPI.  

Building Toward the Big Vision

But what about the visions of ground-breaking business models, ubiquitous connectivity, and enablement of an ever-shifting set of opportunities on big platforms and with unlimited partnership possibilities? Yes, these are still the endpoints to work toward, and fundamentally comprise the strategic reasons to embark on a digital transformation. If your enterprise has the C-Level leadership (in the form of a CDO or CDO-like figure), supported by a well-funded, sophisticated investment approach, by all means, build that new world now.

However, should that vision be shared only within your business unit, a forward-thinking IT group, or a dedicated innovation team, the most important thing to do is to build your team’s capability—and your program’s credibility—while delivering value along the way. The approach we suggest here has been proven in many of the organizations we work with; once your organization begins working faster and at lower costs by orders of magnitude, you’ll have created enough leverage to change the way your organization invests in its API program.

“Cloud Wisdom Weekly: for tech companies and startups” is a new blog series we’re running this fall to answer common questions our tech and startup customers ask us about how to build apps faster, smarter, and cheaper. In this installment, Google Cloud Product Manager Rachel Tsao explores how to save on compute costs with modern container platforms.

Many tech companies and startups are built to operate under a certain degree of pressure and to efficiently manage costs and resources. These pressures have only increased with inflation, geopolitical shifts, and supply chain concerns, however, creating urgency for companies to find ways to preserve capital while increasing flexibility. The right approach to containers can be crucial to navigating these challenges.

In the last few years, development teams have shifted from virtual machines (VMs) to containers, drawn to the latter because they are faster, more lightweight, and easier to manage and automate. Containers also consume fewer resources than VMs, by leveraging shared operating systems. Perhaps most importantly, containers enable portability, letting developers put an application and all its dependencies into a single package that can run almost anywhere.

Containers are central to an organization’s agility, and in our conversations with customers about why they choose Google Cloud, we hear frequently that services like Google Kubernetes Engine (GKE) and Cloud Run help tech companies and startups to not only go to market quickly, but also save money. In this article, we’ll explore five ways to help your business quickly and easily reduce compute costs with containers.

5 ways to control compute costs with containers

Whether your company is an established player that is modernizing its business or a startup building its first product, managed containerized products can help you reduce costs, optimize development, and innovate. The following tips will help you to evaluate core features you should expect of container services and include specific advice for GKE and Cloud Run.

1. Identify opportunities to reduce cluster administration

Most companies want to dedicate resources to innovation, not infrastructure curation. If your team has existing Kubernetes knowledge or runs workloads that need to leverage machine types or graphics processing units (GPUs), you may be able to simplify provisioning with GKE Autopilot. GKE Autopilot provisions and manages the cluster’s underlying infrastructure, all while you pay for only the workload, not 24/7 access to the underlying node-pool compute VMs. In this way, it can reduce cluster administration while saving you money and giving you hardened security best practices by default.

2. Consider serverless to maximize developer productivity

Serverless platforms continue the theme of empowering your technical talent to focus on the most impactful work. Such platforms can promote productivity by abstracting away aspects of infrastructure creation, letting developers work on projects that drive the business while the platform provider oversees hardware and scalability, aspects of security, and more.

For a broad range of workloads that don’t need machine types or GPUs, going serverless with Cloud Run is a great option for building applications, APIs, internal services, and even real-time data pipelines. Analyst research supports that Cloud Run customers achieve faster deployments with less time spent monitoring services, resulting in reinvested productivity that lets these customers do more with fewer resources.

Designed with high scalability in mind, and an emphasis on the portability of containers, Cloud Run also supports a wide range of stateless workloads, including jobs that run to completion. Moreover, it lets you maximize the skills of your existing team, as it does not require cluster management, a Kubernetes skillset or prior infrastructure experience. Additionally, Cloud Run leverages the Knative spec and a container image as a deployment artifact, enabling an easy migration to GKE if your workload needs change.

With Cloud Run, gone are the days of infrastructure overprovisioning! The platform scales down to zero automatically, meaning your services always have the capacity to meet demand, but do not incur costs if there is no traffic.

3. Save with committed use discounts

Committed use discounts provide discounted pricing in exchange for committing to a minimal level of usage in a region for a specified term. If you are able to reliably predict your resource needs, for instance, you can get a 17% discount for Cloud Run (for either one year or three years), and either a 20% discount (for one year) or a 45% discount (for three years) on GKE Autopilot.

4. Leverage cost management features

Minimum and maximum instances are useful for ensuring your services are ready to receive requests but do not cause cost overages. For Google Cloud customers, best practices for cost management include building your container with Cloud Build, which offers pay-for-use pricing and can be more cost efficient than steady-state build farms.

Relatedly, if you choose to leverage serverless containers with Cloud Run, you can set minimum instances to avoid the lag (i.e., the cold start) when a new container instance is starting up from zero. Minimum instances are billed at one-tenth of the general Cloud Run cost. Likewise, if you are testing and want to avoid costs spiraling, you can set a maximum number of instances to ensure your containers do not scale beyond a certain threshold. These settings can be turned off anytime, resulting in no costs when your service is not processing traffic. To have better oversight of costs, you can also view built-in billing reports and set budget alerts on Cloud Billing.

5. Match workload needs to pricing models

GKE Autopilot is great for running highly reliable workloads thanks to its Pod-level SLA. But if you have workloads that do not need a high level of reliability (e.g., fault tolerant batch workloads, dev/test clusters), you can leverage spot pricing to receive a discount of 60% to 91% compared to regularly-priced pods. Spot Pods run on spare Google Cloud compute capacity as long as resources are available. GKE will evict your Spot Pod with a grace period of 25 seconds during times of high resource demand, but you can automatically redeploy as soon as there is available capability. This can result in significant savings for workloads that are a fit.

Innovation requires balance

Put into practice, these tips can help you and your business to get the most out of containers while controlling management and resource costs. That said, it is worth noting that while managing cloud costs is important, the relationship between “cloud” and “cost” is often complex. If you are adopting cloud computing with only the primary goal of saving money, you may soon run into other challenges. Cloud services can save your business money in many ways, but they can also help you get the most value for your money. This balance between cost efficiency and absolute cost is important to keep in mind so that even in challenging economic landscapes, your tech company or startup can continue growing and innovating.

Beyond cost savings, many tech and startup companies are seeking improved business agility, which is the ability to deploy new products and features frequently and with high quality. With deployment best practices built into GKE Autopilot and Cloud Run, you can transform the way your team operates while maximizing productivity with every new deployment.

You can learn if your existing workloads are appropriate for containers with this fit assessment and these guides for migrating to containers. For new workloads, you can leverage these guides for GKE Autopilot and Cloud Run. And for more tips on cost optimization, check out our Architecture Framework for compute, containers, and serverless.

If you want to learn more about how Google Cloud can help your startup, visit our page here to get more information about our program and apply for our Google for Startups Cloud Program, and sign up for our communications to get a look at our community activities, digital events, special offers, and more.

This post shows how to build an image search utility using natural language queries. Our aim is to use different GCP services to demonstrate this. At the core of our project is OpenAI’s CLIP model. It makes use of two encoders – one for images and one for texts. Each encoder is trained to learn representations such that similar images and text embeddings are projected as close as possible.

We will first create a Flask-based REST API capable of handling natural language queries and matching them against relevant images. We will then demonstrate the use of the API through a Flutter-based web and mobile application. Figure 1 shows how our final application would look like:

All the code shown in this post is available as a GitHub repository. Let’s dive in. 

Application at a high-level

Our application will take two queries from the user:

• Tag or keyword query. This is needed in order to pull a set of images of interest from Pixabay. You can use any other image repositories for this purpose. But we found Pixabay’s API to be easier to work with. We will cache these images to optimize the user experience. Suppose we wanted to find images that are similar to this query: “horses amidst flowers”. For this, we’d first pull in a few “horse” images and then run another utility to find out the images that best match our query.  
• Longer or semantic query that we will use to retrieve the images from the pool created in the step above. These images should be semantically similar to this query. 

Note: Instead of two queries, we could have only taken a single long query and run named-entity extraction to determine the most likely important keywords to run the initial search with. For this post, we won’t be using this approach. 

Figure 2 below depicts the architecture design of our application and the technical stack used for each of the components.

Figure 2 also presents the core logic of the API we will develop in bits and pieces in this post. We will deploy this API on a Kubernetes cluster using the Google Kubernetes Engine (GKE). The following presents a brief directory structure of our application code-base:

Next, we will walk through the code and other related components for building our image search API. For various machine learning-related utilities, we will be using PyTorch. 

Building the backend API with Flask

First, we’d need to fetch a set of images with respect to user-provided tags/keywords before performing the natural language image search. The utility below from the pixabay_utils.py script can do this for us:

  def fetch_images_tag(pixabay_search_keyword, num_images):
    """
    Fetches images from Pixabay w.r.t a keyword.
    :param pixabay_search_keyword: Keyword to perform the search on Pixabay.
    :param num_images: Number of images to retrieve.
    :return: List of PIL images.
    :return: List of image URLs.
    """
    query = (
        PIXABAY_API
        + "&q="
        + pixabay_search_keyword.lower()
        + "&image_type=photo&safesearch=true&per_page="
        + str(num_images)
    )
    
    response = requests.get(query)
    output = response.json()

    all_images = []
    all_image_urls = []

    for each in output["hits"]:
        imageurl = each["webformatURL"]
        response = requests.get(imageurl)
        image = Image.open(BytesIO(response.content)).convert("RGB")
        all_images.append(image)
        all_image_urls.append(imageurl)

    return (all_images, all_image_urls)

Note that all the API utilities are logging relevant information. But for brevity, we have omitted the lines of code responsible for that. Next, we will see how to invoke the CLIP model and select the images that would best match a given query semantically.  For this, we’ll be using Hugging Face, an easy-to-use Python library offering state-of-the-art NLP capabilities. We’ll collate all the logic related to this search inside a SimilarityUtil class:

  class SimilarityUtil:
    def __init__(self):
        self.model = CLIPModel.from_pretrained(CLIP_MODEL)
        self.processor = CLIPProcessor.from_pretrained(CLIP_PREPROCESSOR)
        self.device = "cuda" if torch.cuda.is_available() else "cpu"

    def perform_sim_search(self, images, query_phrase, top_k=3):
        """
        Performs similarity search between the images and query.
        :param images: A list of PIL images initially retrieved with
        respect to some entity e.g. Tiger.
        :param query_phrase: A list containing a single text query,
        e.g. "Tiger drinking water".
        :param top_k: Number of top images to return from `images`.
        :return: Top-k indices matching the query semantically and
        their similarity scores.
        """
        model = self.model.to(self.device)
        # Obtain the text-image similarity scores
        with torch.no_grad():
            inputs = self.processor(
                text=[query_phrase], images=images, return_tensors="pt", padding=True
            )
            inputs = inputs.to(self.device)
            outputs = model(**inputs)

        # Image-text similarity scores
        logits_per_image = outputs.logits_per_image.cpu()
        (top_indices, top_scores) = self.sort_scores(logits_per_image, top_k)

        return (top_indices, top_scores)

    def sort_scores(self, scores, top_k):
        """
        Sorts the scores in a descending manner.
        :param scores: Scores to sort through.
        :param top_k: Number of top scores to return.
        :return: Top-k scores and their indices.
        """
        values, indices = scores.squeeze().topk(top_k)
        top_indices, top_scores = [], []

        for score, index in zip(values, indices):
            top_indices.append(int(index.numpy()))
            score = score.numpy().tolist()
            top_scores.append(round(score, 3))

        return (top_indices, top_scores)

CLIP_MODEL uses a ViT-base model to encode the images for generating meaningful embeddings with respect to the provided query. The text-based query is also encoded using A Transformers-based model for generating the embeddings. These two embeddings are matched with one another during inference. To know more about the particular methods we are using for the CLIP model please refer to this documentation from Hugging Face. 

In the code above, we are first invoking the CLIP model with images and the natural language query. This gives us a vector (logits_per_image) that contains the similarity scores between each of the images and the query. We then sort the vector in a descending manner. Note that we are initializing the CLIP model while instantiating the SimilarityUtil to save us the model loading time. This is the meat of our application and we have tackled it already. If you want to interact with this utility in a live manner you can check out this Colab Notebook. 

Now, we need to collate our utilities for fetching images from Pixabay and for performing the natural language image search inside a single script – perform_search.py. Following is the main class of that script:

  class Searcher:
    def __init__(self):
        self.similarity_model = SimilarityUtil()

    def get_similar_images(self, keyword, semantic_query, pixabay_max, top_k):
        """
        Finds semantically similar images.
        :param keyword: Keyword to search with on Pixabay.
        :param semantic_query: Query to find semantically similar images retrieved from Pixabay.
        :param pixabay_max: Number of maximum images to retrieve from Pixabay.
        :param top_k: Top-k images to return.
        :return: Tuple of top_k URLs and the similarity scores of the images present inside the URLs.
        """
        images_redis_key = keyword + "_images"
        urls_redis_key = keyword + "_urls"

        if redis_client.exists(images_redis_key) and redis_client.exists(
            urls_redis_key
        ):
            keyword_images = redis_client.get(images_redis_key)
            keyword_image_urls = redis_client.get(urls_redis_key)
        else:
            (keyword_images, keyword_image_urls) = fetch_images_tag(
                keyword, pixabay_max
            )
            redis_client.set(images_redis_key, keyword_images)
            redis_client.set(urls_redis_key, keyword_image_urls)

        (top_indices, top_scores) = self.similarity_model.perform_sim_search(
            keyword_images, semantic_query, top_k
        )

        top_urls = [keyword_image_urls[index] for index in top_indices]

        return (top_urls, top_scores)

Here, we are just calling the utilities we had previously developed to return the URLs of the most similar images and their scores. What is even more important here is the caching capability. For that, we combined GCP’s MemoryStore and a Python library called direct-redis. More on setting up MemoryStore later. 

MemoryStore provides a fully managed and low-cost platform for hosting Redis instances. Redis databases are in memory and light-weight making them an ideal candidate for caching. In the code above, we are caching the images fetched from Pixabay and their URLs. So, in the event of a cache hit, we won’t need to call the CLIP model and this will tremendously improve the response time of our API. 

Other options for caching

We can cache other elements of our application. For example, the natural language query. When searching through the cached entries to determine if it’s a cache hit, we can compare two queries for semantic similarity and return results accordingly. 

Consider that a user had entered the following natural language query: “mountains with dark skies”. After performing the search, we’d cache the embeddings of this query. Now, consider that another user entered another query: “mountains with gloomy ambiance”. We’d compute its embeddings and run a similarity search with the cached embeddings. We’d then compare the similarity scores with respect to a threshold and parse the most similar queries and their corresponding results. In case of a cache miss, we’d just call the image search utilities we developed above. 

When working on real-time applications we often need to consider these different aspects and decide what enhances the user experience and maximizes business at the same time. 

All that’s left now for the backend is our Flask application – main.py:

  @app.route("/search", methods=["GET"])
def get_images():
    tag = request.args.get("t").lower()
    query = request.args.get("s_query").lower()
    top_k = request.args.get("k")

    (top_urls, top_scores) = searcher.get_similar_images(
        tag, query, MAX_PIXABAY_SEARCH, int(top_k)
    )

    return jsonify({"top_urls": top_urls, "top_scores": top_scores})

Here we are first parsing the query parameters from the request payload of our search API.  We are then just calling the appropriate function from perform_search.py to handle the request. This Flask application is also capable of handling CORS. We do this via the flask_cors library:

  cors = CORS(
    app,
    resources={
        r"/search/*": {"origin": "*"},
        r"/test/*": {"origin": "*"},
    },
)

And this is it! Our API is now ready for deployment. 

Deployment with Compute Engine and GKE

The reason why we wanted to deploy our API on Kubernetes is because of the flexibility Kubernetes offers for managing deployments. When operating at scale, auto scalability and load balancing are very important. With the comes the requirement of security — we’d not want to expose the utilities for interacting with any internal services such as databases. With Kubernetes, we can achieve all these easily and efficiently. 

GKE provides secured and fully managed functionalities for operationalizing Kubernetes clusters. Here are the steps to deploy the API on GKE at a glance:

• We first build a Docker image for our API and then push it to the Google Container Registry (GCR).
• We then create a Kubernetes cluster on GKE and initialize a deployment.
• We then add scalability options.
• If any public exposure is needed for the API, we then tackle it. 

We can assimilate all the above into a shell script – k8s_deploy.sh:

  ## Docker build and push ## 
# We are inside the `server` directory
docker build -t gcr.io/${PROJECT_ID}/search_service .
docker push gcr.io/${PROJECT_ID}/search_service

## Deploy on a GKE cluster ##
# Configure the Docker command-line tool to authenticate to Container Registry
gcloud auth configure-docker

# Create a Kubernetes cluster
gcloud container clusters create image-search-nlp 

# Create a deployment
kubectl create deployment clip-search --image=gcr.io/${PROJECT_ID}/search_service

# Number of worker replicas
kubectl scale deployment clip-search --replicas=3

# HorizontalPodAutoscaler resource
kubectl autoscale deployment clip-search --cpu-percent=80 --min=1 --max=5

# Expose deployment
kubectl  expose deployment clip-search --name=clip-search-service --type=LoadBalancer --port 80 --target-port 8080

These steps are well explained in this tutorial that you might want to refer to for more details. We can configure all the dependencies on our local machine and execute the shell script above. We can also use the GCP Console to execute it since a terminal on the GCP Console is pre-configured with the system-level dependencies we’d need. In reality, the Kubernetes cluster should only be created once and different deployment versions should be created under it. 

After the above shell script is run successfully, we can run kubectl get service to know the external IP address of the service we just deployed:

  NAME                       CLUSTER-IP    EXTERNAL-IP     PORT(S)          AGE
clip-search-service      10.3.251.122    203.0.113.0     80:30877/TCP     10s

We can now consume this API with the following base URI: http://203.0.113.0/. If we wanted to deal with only http-based API requests, then we are done here. But secured communication is often a requirement in order for applications to operate reliably. In the following section, we are to discuss how to configure the additional items to allow our Kubernetes cluster to allow https requests.  

Configurations for handling https requests with GKE

A secure connection is almost often a  must-have requirement in modern client/server applications. The front-end Flutter application would be hosted on GitHub Pages for this project, and it requires https-based connection as well. Even if configuring https connection particularly for a GKE-based cluster can be considered a chore, its setup might seem daunting at first.

There are six steps to configure https connection in the GKE environment: 

1. You need to have a domain name, and there are a lot of inexpensive options that you can buy. For instance, mlgde.com domain for this project is acquired via Gabia which is a Korean service provider.
2. A reserved (static) external IP address has to be acquired via gcloud command or GCP console. 
3. You need to bind the domain name with the acquired external IP address. This is a platform-specific configuration that issued the domain name to you. 
4. There is a special ManagedCertificate resource which is specific to the GKE environment. ManagedCertificate resource specifies the domain that the SSL certificate will be created for, so you need this. 
5. An Ingress resource should be created by listing the static external IP address, ManagedCertificate resource, and the service name and port which the incoming traffic will be routed to. The Service resource could remain the same as in the above section with only changes from LoadBalancer to ClusterIP. 
6. Last but not least, you need to modify the existing Flask application and Deployment resource to support liveness and readiness probes which are used to check the health status of the Deployment. The Flask application side can be simply modified with the flask-healthz Python package, and you only need to add livenessProbe and readinessProbe sections in the Deployment resource. In the code example below, the livenessProbe and readinessProbe are checked via /alive and /ready endpoints respectively.

  from flask_healthz import healthz
from flask_healthz import HealthError


app = Flask(__name__)
app.register_blueprint(healthz, url_prefix="/")


def printok():
   print("Everything is fine")


def liveness():
   try:
       printok()
   except Exception:
       raise HealthError("Can't connect to the file")


def readiness():
   try:
       printok()
   except Exception:
       raise HealthError("Can't connect to the file")


app.config.update(
   HEALTHZ = {
       "alive": "main.liveness",
       "ready": "main.readiness",
   }
)

One thing to be careful of is the initialDelaySeconds attribute of the probes. It is uncommon to configure this attribute with a big number, but it could be bigger than 90 – 120 seconds depending on the size of the model to be used. For this project, it is configured in 90 seconds in order to wait until the CLIP model is fully loaded into memory (full YAML script here).

  livenessProbe:
 httpGet:
   path: /alive
   port: 8080
 initialDelaySeconds: 90
 periodSeconds: 10

readinessProbe:
 httpGet:
   path: /ready
   port: 8080
 initialDelaySeconds: 90
 periodSeconds: 10

Again, these steps may seem daunting at first, but it will become clear when you have done it once. Here is the official document for Using Google-managed SSL certificates You can find all the GKE-related resources used in this project here. 

Once every step is completed you should be able to see your server application running on the GKE environment. Please make sure to run kubectl apply command whenever you create Kubernetes resources such as Deployment, Service, Ingress, and ManagedCertificate, and it is important to wait for more than 10 minutes until the ManagedCertifcate provisioning is done. 

You can run gcloud compute addresses list command to find out the static external IP address that you have configured.

  NAME  ADDRESS/RANGE  TYPE      PURPOSE  NETWORK  REGION  SUBNET  STATUS
gde      34.149.231.34       EXTERNAL                                                                    IN_USE

Then, the IP address has to be mapped to the domain. Figure 3 is a screenshot of a dashboard from where we got the mlgde.com domain. It clearly shows mlgde.com is mapped to the static external IP address configured in GCP.

In case you’re wondering why we didn’t deploy this application on App Engine, well that is because of the compute needed to execute the CLIP model. App Engine instance won’t fit in that regime. We could have also incorporated compute-heavy capabilities via a VPC Connector. That is a design choice that you and your team would need to consider. In our experiments, we found the GKE deployment to be easier and suitable for our needs. 

Infrastructure for the CLIP model

As mentioned earlier, at the core of our application is the CLIP model. It is computationally a bit more expensive than the regular deep learning models. This is why it makes sense to have the hardware infrastructure set up accordingly to execute it. We ran a small benchmark in order to see how a GPU-based environment could be beneficial here. 

We ran the CLIP on a Tesla P100-based machine and also on a standard CPU-only machine 1000 times. The code snippet below is the meat of what we executed:

  DEVICE = "cuda" if torch.cuda.is_available() else "cpu"

start_time = time.time()
for _ in range(1000):
    with torch.no_grad():
        model = model.to(DEVICE)
        inputs = processor(text=[semantic_search_phrase], 
                        images=all_images, return_tensors="pt", padding=True)
        inputs = inputs.to(DEVICE)
        outputs = model(**inputs)
end_time = time.time() - start_time
print(f"Total time: {end_time:.3f} seconds.")

As somewhat expected, with the GPU, the code took 13 minutes to complete execution. With no GPU, it took about 157 minutes.

It is uncommon to leverage GPUs for model prediction because of cost restrictions, but sometimes we have to access GPUs for deploying a big model like CLIP. We configured a GPU-based cluster on GKE and compared the performance differences with and without it. It took about 1 second to handle a request with GPU and MemoryStore cache while it took more than 4 seconds with MemoryStore only (without the GPUs). 

For the purposes of this post, we used a CPU-based cluster on Kubernetes. But It is easy to configure GPU usage in a GKE cluster. This document shows you how to do so. For a short summary, there are two steps. First, a node should be configured with GPUs when creating a GKE cluster. Second, GPU drivers should be installed in GKE nodes. You don’t need to visit and manually install GPU drivers for each node by yourself. Rather you can simply apply the DaemonSet resource to GKE as described here.

Setting up MemoryStore

In this project, we first query the general concept of images to Pixabay, then we filter the images with a semantic query using CLIP. It means we can cache the initially retrieved images from Pixabay for the next specific semantic query. For instance, you may want to search with “gentleman wearing tie” at first, then you may want to retry searching for “gentleman wearing glass”. In this case, the base images remain all the same, so they could be stored in a cache server like Redis. 

MemoryStore is a GCP service wrapping the Redis which is an in-memory data store, so you can simply use a standard Redis Python package for accessing it. The only thing to be careful about when provisioning a MemoryStore Redis instance is to make sure it is in the same region where your GKE cluster or Compute Engine instance is.

The code snippet below shows how to make a connection to the Redis instance in Python. Nothing specific to GCP, but you only need to be aware of the usage of the standard redis-py package. 

  # REDISHOST is the IP address to the MemoryStore instance
redis_host = os.environ.get("REDISHOST", "localhost")
redis_port = int(os.environ.get("REDISPORT", 6379))
redis_client = redis.StrictRedis(host=redis_host, port=redis_port)

After creating a connection, you can store and retrieve data from MemoryStore. There are more advanced use cases of Redis, but we only used exists, get, and set methods for the demonstration purpose. These methods should be very familiar if you know maps, dictionaries, or other similar data structures. For the code portion that uses Redis-related utilities, please refer to the Searcher Python class we discussed in an earlier section. 

In the URLs below, you can find side-by-side comparisons of using MemoryStore:

• Without MemoryStore: https://youtu.be/7B88Eyrd-4s
• With MemoryStore (1st try): https://youtu.be/LE6xeEIRuMM
• With MemoryStore (2nd try): https://youtu.be/rRfK17sdk84 

Putting everything together

All that’s left now is to collate the different components we developed in the sections above and deploy our application with a frontend. All the frontend-related code is present here. 

• The front-end application is written in the Flutter development kit. The main screen contains two text fields for queries to Pixabay and CLIP model respectively. When you click the “Send Query” button, it will send out a RestAPI request to the server. After receiving the result back from the server, the retrieved images from the semantic query will be displayed at the bottom section of the screen. 
  • Please note that a Flutter application can be deployed to various environments including desktop, web, iOS, and Android. In order to keep as simple as possible, we chose to deploy the application to the GitHub Pages. Whenever there is any change to a client-side source directory, the GitHub Action will be triggered to build a web page and deploy the latest version to the GitHub Pages. 

Our final application is deployed here and it looks like so:

Note that due to constraints, the above-mentioned URL will only be live for one or two months.  

It is also possible to redeploy the back-end application with a GitHub Action. 

• The very first step is to craft a Dockerfile like below. Since Python is a scripting language, and there are lots of heavy packages that the application is dependent on, it is important to cache the steps. For instance, installing the dependencies should be separated from other commands.

  FROM pytorch/pytorch:latest
WORKDIR /app

# install the dependencies
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt

COPY . .  

# set up environment variables
ENV PIXABAY_API_KEY="..."
ENV REDIS_IN_USE="true"
ENV REDISHOST="..."

# expose port that Flask app is listening on
EXPOSE 8080

# run the Flask app
CMD [ "python3", "main.py" ]

• With the Dockerfile defined, we can use a GitHub Action like this for automatic deployment. 

Edge cases

Since the CLIP model is pre-trained on a large corpus of image and text pairs it’s likely that it may not generalize well to every natural language query we throw at it. Also, because we are limiting the number of images on which the CLIP model can operate, this somehow restricts the expressivity of the model.

We may be able to improve the performance for the second situation by increasing the number of images to be pre-fetched and by indexing them into a low-cost and high-performance database like Datastore. 

Costs

In this section, we wanted to provide the readers a breakdown of the costs they might incur in order to consume the various services used throughout the application. 

• Frontend hosting
  • The front-end application is hosted on GitHub Pages, so there is no expenditure for this.
• Compute Engine
  • With an e2-standard-2 instance type without GPUs, the cost is around $48.92 per month. In case you want to add a GPU (NVIDIA K80), the cost goes up to $229.95 per month.
• MemoryStore
  • The cost for MemoryStore depends on the size. With 1GB of space, the cost is around $35.77 per month, and whenever you add more GBs the cost will be doubled.
• Google Kubernetes Engine
  • The monthly cost for a 3 node GKE cluster with n2-standard-2 (vCPUs: 2, RAM: 8GB without GPUs) is about $170.19. If you add one GPU (NVIDIA K80) to the cluster, the cost goes up to $835.48.

While you may think that is a lot cost-wise, it is good to know that Google gives away free $300 credits when you create a new GCP account. It is still not enough for leveraging GPUs, but it is enough to learn and experiment with GKE and MemoryStore usage.

Conclusion

In this post, we walked through the components needed to build a basic image search utility for natural language queries. We discussed how these different components are connected to each other. Our image search API is able to utilize caching and was deployed on a Kubernetes cluster using GKE. These elements are essential when building a similar service to cater to a much bigger workload. We hope this post will serve as a good starting point for that purpose. Below are some references on similar areas of work that you can explore:

• Building a real-time embeddings similarity matching system
• Detecting image similarity using Spark, LSH and TensorFlow

Acknowledgments: We are grateful to the Google Developers Experts program for supporting us with GCP credits. Thanks to Karl Weinmeister and Soonson Kwon of Google for reviewing the initial draft of this post.