# Time Freezing

> Freeze time during Keploy test runs to handle JWT tokens and time-sensitive data — ensure consistent, reliable test results.

## Why Time Freezing? ❄️

While making tests, **time-sensitive objects like JWT tokens are a challenge** as they expire, leading to test failures. This increases the maintenance effort of test suites and also impacts reliability.

## What is Time Freezing? ⏳

With Keploy Cloud users will be able to **freeze/rollback the time in every test run, back to when the test case was recorded.**

This allows developers to ensure time-sensitive objects don’t expire or change, **making tests consistent and more reliable.**

## Usage 🛠️

### Running on Linux or Windows(WSL) 🐧💻

For native Linux, Windows(WSL) environments, simply **add the `--freezeTime` flag** when running your tests, like so:

```bash
keploy test -c "<appCmd>" --freezeTime
```

Voila! Your tests will now run with time freezing enabled.

### Running on Docker 🐳

For Docker-based applications, you'll need to make a few adjustments to your Dockerfile to utilize this feature:

1. First, check your system architecture

```sh
uname -a
```

2. Download the appropriate time freeze agent for your architecture & set the `LD_PRELOAD` Environment Variable in your Dockerfile

### For Golang(Go) Applications -

> Note: Time freezing works on every Go version that supports the `faketime` build tag, i.e. all currently supported Go releases. The mechanism is build-time (the `-tags=faketime` flag swaps Go's `time` package to read from a runtime agent file instead of the OS clock), so it's not tied to any specific Go version.

#### amd64/x86_64 🖥️

```Dockerfile
# Download the time freeze agent
ADD https://keployenterprise.blob.core.windows.net/releases/latest/assets/go_freeze_time_amd64 /lib/keploy/go_freeze_time_amd64

# set suitable permissions
RUN chmod +x /lib/keploy/go_freeze_time_amd64

# run the binary
RUN /lib/keploy/go_freeze_time_amd64

# build your binary with fake time (during test mode)
RUN go build -tags=faketime <your_main_file>

```

OR

#### arm64/aarch64 📱

```Dockerfile
# Download the time freeze agent

ADD https://keployenterprise.blob.core.windows.net/releases/latest/assets/go_freeze_time_arm64 /lib/keploy/go_freeze_time_arm64

# set suitable permissions
RUN chmod +x /lib/keploy/go_freeze_time_arm64

# run the binary
RUN /lib/keploy/go_freeze_time_arm64

# build your binary with fake time (during test mode)
RUN go build -tags=faketime <your_main_file>
```

3. Only Add `faketime` tag to your build script during **Test MODE**

4. Re-Build your Docker image.
5. Now **add the `--freeze-time` flag** when running your tests with Keploy, like so:

```bash
keploy test -c "<appCmd>" --freeze-time
```

Voila! Your tests will now run with time freezing enabled.

### For Node/Java/Python Applications -

#### amd64/x86_64 🖥️

```Dockerfile
# Download the time freeze agent
ADD https://keployenterprise.blob.core.windows.net/releases/latest/assets/freeze_time_amd64.so /lib/keploy/freeze_time_amd64.so

#set suitable permissions
RUN chmod +x /lib/keploy/freeze_time_amd64.so

# Set LD_PRELOAD environment variable to use freeze_time_amd64.so
ENV LD_PRELOAD=/lib/keploy/freeze_time_amd64.so
```

OR

#### arm64/aarch64 📱

```Dockerfile
# Download the time freeze agent
ADD https://keployenterprise.blob.core.windows.net/releases/latest/assets/freeze_time_arm64.so /lib/keploy/freeze_time_arm64.so

#set suitable permissions
RUN chmod +x /lib/keploy/freeze_time_arm64.so

# Set LD_PRELOAD environment variable to use freeze_time_arm64.so
ENV LD_PRELOAD=/lib/keploy/freeze_time_arm64.so
```

3. Re-Build your Docker image.
4. Now **add the `--freeze-time` flag** when running your tests with Keploy, like so:

```bash
keploy test -c "<appCmd>" --freeze-time
```

Voila! Your tests will now run with time freezing enabled.