# In this How-To we explain how you setup IntelliJ IDEA

First of all you can download IntelliJ here: https://lp.jetbrains.com/intellij-idea-promo/

# Basic steps

```
git clone git@github.com:atlarge-research/opendc
```

Check if you have a compatible java version available. Make sure to have one of these versions available: [19, 20, 21]

If not install a supported version!

On a MAC

```
/usr/libexec/java_home -V
```

On Debian

```
update-alternatives --list java
```

On Redhat/Centos

```
yum list installed | grep java
```


Open the project in IntelliJ

![Intellij Open Project](img/intellij_open_project.png)

Now fix the settings so that you use the correct java version. (In the example the java version is set to "21")
Navigation path in the settings pannel: "Build, Execution, Deployment" -> "Build Tools" -> "Gradle"

![Intellij Settings](img/intellij_settings.png)

Now navigate in the file menu to and open the file: "gradle"/"libs.versions.toml"

Make sure the java version is set to the same version as previously cofigured in the settings.

![Intellij Libs Versions Toml](img/intellij_libs_versions_toml.png)


Now open the Gradle panel on the right-hand side of the editor (1) and hit the refresh button at the top of the panel (2).

![Intellij Gradle Panel](img/intellij_gradle_panel.png)


# Setup your first experiment and run it from source


Create a directory where you are going to put the files for your first experiment.

File structure:

![Experiment File Structure](img/experiment_file_structure.png)

You can download the example workload trace (bitbrains-small-9d2e576e6684ddc57c767a6161e66963.zip) [here](https://atlarge-research.github.io/opendc/assets/files/bitbrains-small-9d2e576e6684ddc57c767a6161e66963.zip)

Now unzip the trace.

The content of "topology.json"

```
{
    "clusters":
    [
        {
            "name": "C01",
            "hosts" :
            [
                {
                    "name": "H01",
                    "cpu":
                    {
                        "coreCount": 32,
                        "coreSpeed": 3200
                    },
                    "memory": {
                        "memorySize": 256000
                    }
                }
            ]
        },
        {
            "name": "C02",
            "hosts" :
            [
                {
                    "name": "H02",
                    "count": 6,
                    "cpu":
                    {
                        "coreCount": 8,
                        "coreSpeed": 2930
                    },
                    "memory": {
                        "memorySize": 64000
                    }
                }
            ]
        },
        {
            "name": "C03",
            "hosts" :
            [
                {
                    "name": "H03",
                    "count": 2,
                    "cpu":
                    {
                        "coreCount": 16,
                        "coreSpeed": 3200
                    },
                    "memory": {
                        "memorySize": 128000
                    }
                }
            ]
        }
    ]
}
```

The content of "experiment.json"

The paths in the "experiment.json" file are relative to the "working directory" which is configured next.


```
{
    "name": "simple",
    "topologies": [{
        "pathToFile": "topology.json"
	}],
    "workloads": [{
        "pathToFile": "bitbrains-small",
        "type": "ComputeWorkload"
    }]
}
```

In the project file structure on the left open the following file:

"opendc-experiments"/"opendc-experiments-base"/"src"/"main"/"kotlin"/"org.opendc.experiment.base"/"runner"/"ExperimentCLi.kt"

![Intellij Experimentcli](img/Intellij_experimentcli.png)

Now open the "Run/Debug" configuration (top right).

![Intellij Open Run Config](img/intellij_open_run_config.png)

We need to edit two settings:

"Program arguments": --experiment-path experiment.json

"Working Directory": a path where you have put the experiment files

![Intellij Edit The Run Config](img/intellij_edit_the_run_config.png)

Now you can click "Run" and start your first experiment.

In the working directory a "output" direcotry is created with the results of the experiment.