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Sample Real-Time App (Svelte)​

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Introduction​

🪄 Dive into the world of realtime subscriptions and see how seamlessly Keploy integrates with SSE and MongoDB Buckle up, it's gonna be a fun ride! 🎢

🛠️ Platform-Specific Requirements for Keploy​

Below is a table summarizing the tools needed for both native and Docker installations of Keploy on macOS, Windows, and Linux:

Operating SystemWithout DockerDocker InstallationPrerequisites
macOS macOSSupported Native, Apple Silicon (Go, Node, Python, Java)GuideNative: nothing to install — no Docker, no Lima, no sudo.
Only if you choose a container route: Docker Desktop 4.25.2+, or Lima (which is also the route on an Intel Mac).
Windows WindowsSupported Native, x86‑64 (Go, Node, Python, Java)GuideNative: nothing to install — no WSL, no Docker, no Administrator.
Only if you choose a container route: WSL (wsl --install, Windows 10 2004+/build 19041+ or Windows 11 — also the route on Windows/ARM), or Docker Desktop 4.25.2+.
Linux LinuxSupportedSupportedLinux kernel 5.10 or higher

Keploy runs natively on macOS (Apple Silicon / arm64) and Windows (x86‑64) — neither has eBPF, so it intercepts traffic in userspace on both, and neither needs sudo or Administrator. Natively on macOS and Windows, Keploy understands HTTP/HTTPS, MySQL and MongoDB calls; calls to other services — PostgreSQL, Redis, Kafka, gRPC and the like — are captured only as raw bytes and usually don't replay, so for an app that runs in containers or depends on them, use Docker. Docker, Lima (macOS) and WSL (Windows) remain supported alternatives, and WSL is the route on Windows on ARM. On an Intel Mac use Lima: the Docker route on macOS still runs the native CLI on the host, so it is Apple Silicon only too.

Low-latency recording (keploy record --low-latency, or a Kubernetes Sidecar with low_latency_mode) and the Kubernetes DaemonSet agent capture with eBPF hooks that arm64 kernels support only from 6.4 (x86-64 kernels from 5.10). On an older arm64 kernel, record without low latency, and use Sidecar mode without low_latency_mode in Kubernetes.

Podman​

On Linux, Keploy records and tests applications that run in Podman as well as in Docker. In a keploy record or keploy test command, use podman run (or podman compose) where these docs use docker run (or docker compose). Run every other container command they give, such as creating the network, building the image or starting a database with docker run -d, as sudo podman ..., so that it is in the rootful Podman Keploy uses. See the Podman tab under Linux in Installing Keploy for the commands.

  • Rootful Podman. Keploy's agent loads eBPF, which a rootless Podman can't grant, so Keploy drives the rootful Podman and runs as root (it re-runs itself with sudo when it needs to). Images and containers you created with Podman without sudo aren't visible to it: build or pull your app's image with sudo podman.
  • Podman's API. Keploy talks to Podman's Docker-compatible API. If the rootful podman.socket is enabled (sudo systemctl enable --now podman.socket) it uses that; otherwise it starts Podman's API service for the run and stops it when Keploy exits.
  • Compose. podman compose (Podman 4.7 or later; Keploy is tested with Podman 5) works with Docker Compose v2 or later (docker-compose) as its compose provider, on a host that runs systemd: Podman runs healthchecks with systemd timers, and your app's service waits for the healthcheck of Keploy's agent service. podman-compose isn't supported.
  • Local Podman on Linux only. A Podman set up as a podman-remote client (for example with CONTAINER_HOST, CONTAINER_CONNECTION, or remote = true in containers.conf) runs containers in another Podman service, but Keploy's agent runs in the local rootful Podman, so Keploy refuses it. On macOS and Windows, including Podman machine, Keploy refuses Podman commands: its agent uses Linux's eBPF.
  • Which Keploy. Podman support is in the Keploy that curl --silent -O -L https://keploy.io/install.sh && source install.sh installs (free with an account), from v3.8.60. A keploy built from the open-source repository refuses Podman commands and says where to get it.

Installation Overview​

The install is the same whatever your plan. You need a free Keploy account to record and replay: the first keploy record or keploy test signs you in, and your plan decides which additional features are available.

Quick Installation Using CLI​

On Linux and macOS (Apple Silicon), install Keploy with:

 curl --silent -O -L https://keploy.io/install.sh && source install.sh

You should see something like this:

       ▓██▓▄
    ▓▓▓▓██▓█▓▄
     ████████▓▒
          ▀▓▓███▄      ▄▄   ▄               ▌
         ▄▌▌▓▓████▄    ██ ▓█▀  ▄▌▀▄  ▓▓▌▄   ▓█  ▄▌▓▓▌▄ ▌▌   ▓
       ▓█████████▌▓▓   ██▓█▄  ▓█▄▓▓ ▐█▌  ██ ▓█  █▌  ██  █▌ █▓
      ▓▓▓▓▀▀▀▀▓▓▓▓▓▓▌  ██  █▓  ▓▌▄▄ ▐█▓▄▓█▀ █▓█ ▀█▄▄█▀   █▓█
       ▓▌                           ▐█▌                   █▌
        ▓

Keploy CLI

Available Commands:
  example           Example to record and test via keploy
  config --generate generate the keploy configuration file
  record            record the keploy testcases from the API calls
  test              run the recorded testcases and execute assertions
  update            Update Keploy

Flags:
      --debug     Run in debug mode
  -h, --help      help for keploy
  -v, --version   version for keploy

Use "keploy [command] --help" for more information about a command.

🎉 Wohoo! You are all set to use Keploy.

On Windows (x86-64), Keploy is a single keploy.exe, installed from PowerShell without Administrator — see Run Keploy natively on Windows.

Other Installation Methods​

Install using Docker

Downloading and running Keploy in Docker

With this method your application and Keploy's agent run in Docker, but the keploy CLI — which starts them both — runs on your machine. Use it when your app runs in containers, or on macOS and Windows when your app depends on services beyond HTTP/HTTPS, MySQL and MongoDB: natively there, calls to other services — PostgreSQL, Redis, Kafka, gRPC and the like — are captured only as raw bytes and usually don't replay.

  1. Open up a terminal window.

  2. Create a bridge network in Docker using the following docker network create command:

docker network create keploy-network
  1. Install Keploy: on Linux and macOS with the command below, on Windows with the PowerShell steps. On macOS the CLI is Apple Silicon (arm64) only — on an Intel Mac, run Keploy with Lima instead.
 curl --silent -O -L https://keploy.io/install.sh && source install.sh

Examples:​

Record:

keploy record -c "docker run -p <appPort>:<hostPort> --name <containerName> --network keploy-network <applicationImage>" --container-name "<containerName>" --buildDelay 60

Test:

keploy test --c "docker run -p <appPort>:<hostPort>  --name <containerName> --network keploy-network <applicationImage>" --delay 10
Install using Podman (Linux)

Keploy also records and tests applications that run in rootful Podman on Linux, started with podman run or podman compose: see the Podman tab under Linux in Installing Keploy.

Install Manually

Downloading the Keploy binary yourself

These download the same keploy binary the install command above installs.

On Linux​

Prerequisite: Linux kernel 5.10 or higher (uname -r shows yours). This picks the build for your architecture:

case "$(uname -m)" in
  x86_64) ARCH=amd64 ;;
  aarch64 | arm64) ARCH=arm64 ;;
  *) echo "unsupported architecture: $(uname -m)" >&2; false ;;
esac &&
  curl --fail --silent --show-error --location -o /tmp/keploy \
    "https://keploy.io/ent/dl/latest/enterprise_linux_${ARCH}" &&
  sudo install -m 0755 /tmp/keploy /usr/local/bin/keploy

The same steps work inside WSL on Windows and inside a Lima VM on macOS.

On macOS (Apple Silicon)​

mkdir -p ~/.keploy/bin &&
  curl --fail --silent --show-error --location -o ~/.keploy/bin/keploy \
    "https://keploy.io/ent/dl/latest/enterprise_darwin_arm64" &&
  chmod +x ~/.keploy/bin/keploy
export PATH="$HOME/.keploy/bin:$PATH"   # add this line to your ~/.zshrc too

There is no Intel macOS build: on an Intel Mac, use the Linux steps inside Lima.

On Windows (x86-64)​

Follow the PowerShell steps. On Windows on ARM, use the Linux steps inside WSL.

If you run Keploy inside WSL with Docker: setting up Docker Desktop for WSL 2

  1. Install Docker Desktop for Windows from here.

When developing on Windows with Docker Desktop and WSL 2, it's crucial to configure Docker Desktop to allow WSL 2 distributions to access the Docker daemon. This setup enables seamless integration between your Windows environment, WSL 2 Linux distros, and Docker.

By default, Docker Desktop may not be configured to work with all WSL 2 distros out of the box. Proper configuration ensures that you can run Docker commands from within your WSL 2 environment, allowing for a more native Linux development experience while leveraging the power of Windows.

This setup is essential for Keploy to function correctly in a WSL 2 environment, as it needs to interact with the Docker daemon to manage containers and networks effectively. For detailed instructions on how to configure Docker Desktop for WSL 2, please refer to the official Docker documentation.

Installation 📥​

Ways you can run this sample application.

Installation Setup​

This runs natively on Linux, macOS (Apple Silicon) and Windows (x86-64) — see Installing Keploy.

Server​

git clone https://github.com/keploy/samples-go.git && cd samples-go/sse-svelte
go mod download

Start MongoDB Instance​

Using the docker-compose file we will start our mongodb instance:-

# Start MongoDB
docker-compose up mongo

Build Application Binary​

Now, we will create the binary of our application:-

go build -cover

Once we have our applicaiton binary ready, we will start the application with keploy to start capturing the testcases.

Capture the test cases​

sudo -E keploy record -c "./sse-mongo"

sudo -E is needed on Linux (and WSL) only — on macOS and Windows, run keploy record -c "./sse-mongo" without it (on Windows, use .\sse-mongo.exe in place of ./sse-mongo, here and in keploy test below).

Start the UI​

We will capture our test from the UI written in Svelte.js

cd svelte-app && npm install && npm run dev

Now let's click on GetTime button to trigger the event. We would notice that keploy will capture those calls : - Testcases

Run the Testcases​

Now let's run the test mode :-

keploy test -c "./sse-mongo" --delay 10 --goCoverage

Output should look like : -

Testrun

So no need to setup fake database/apis like Postgres or write mocks for them. Keploy automatically mocks them and, The application thinks it's talking to MongoDb 😄. And with just few clicks we were able to get 42% code coverage of our go backend application.