BuildPythonBase.java

import com.wannaverse.ignition.sdk.Ignition;
import com.wannaverse.ignition.sdk.SnapshotHandle;
import com.wannaverse.ignition.sdk.Vm;
import com.wannaverse.ignition.sdk.VmImage;

import java.nio.file.Files;
import java.nio.file.Path;
import java.time.Duration;

/** Run using: ignitionctl create BuildPythonBase.java */
void main() throws Exception {
    /** Build the Python image */
    Ignition ignition = Ignition.connect();
    Duration installBudget = Duration.ofMinutes(10);
    Vm builder = ignition.run("python-builder");
    builder.execChecked(installBudget, "apt-get", "update");
    builder.aptInstall(installBudget, "python3");
    String version = builder.exec("python3", "--version").stdout().strip();
    builder.kill();
    builder.commit("python-base");
    builder.remove();

    /** Add our application to the new python image */
    Path index = Files.writeString(Files.createTempDirectory("python-app").resolve("index.html"),"<h1>served by " + version + " in a microVM</h1>\n");
    VmImage app = ignition.deploy("python-hello", index)
            .base("python-base")
            .entrypoint("python3 -m http.server 8080 --directory /opt/app")
            .create();

    /** Create a python vm */
    Vm warmup = ignition.run("python-hello-warmup", app);
    IO.println("Python app booted at http://" + warmup.ipAddress() + ":8080/");

    /** Run our "hot" path a few times to warm it up */
    for (int i = 0; i < 5; i++) {
        warmup.execChecked(Duration.ofSeconds(10), "curl", "-sf", "-o", "/dev/null", "http://127.0.0.1:8080/index.html");
    }

    /** Snapshot the warm image and remove the running vm  */
    SnapshotHandle warm = warmup.snapshot("python-hello-warm");
    warmup.remove();

    // Later we can do: ignitionctl run --snapshot python-hello-warm --name python-hello-N
}