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package io.github.jshipit;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
public class ContainerManager {
private String containerName;
private String containerRepo;
private String containerImage;
private String containerTag;
private String containerApiRepo;
private String containerCommand;
private OCIDataStore dataStore;
public ContainerManager(String containerName, String containerImage, String containerTag, String containerApiRepo, String containerRepo, OCIDataStore dataStore) {
this.containerName = containerName;
this.containerImage = containerImage;
this.containerTag = containerTag;
this.containerApiRepo = containerApiRepo;
this.containerRepo = containerRepo;
this.dataStore = dataStore;
}
public ContainerManager(String containerName, String containerCommand, OCIDataStore dataStore) {
this.containerName = containerName;
this.containerImage = dataStore.getContainerImage(containerName);
this.containerTag = dataStore.getContainerTag(containerName);
this.containerApiRepo = dataStore.getContainerApiRepo(containerName);
this.containerRepo = dataStore.getContainerRepo(containerName);
this.containerCommand = containerCommand;
this.dataStore = dataStore;
}
/*
* Create a container directory
*/
public void createContainer() {
System.out.println("Creating container");
if (dataStore.containerExists(this.containerName)) {
System.out.println("Container already exists");
return;
}
if (!Files.isDirectory(Paths.get(dataStore.getPath() + "/" + this.containerImage + "/" + this.containerTag))) {
System.out.println("Image does not exist");
return;
}
String containerDirectory = dataStore.createContainerDirectory(this.containerImage, this.containerTag, this.containerName, this.containerApiRepo, this.containerRepo);
new File(containerDirectory + "/containerOverlay").mkdirs(); // The upper directory of the overlay mount, user data and any changes to root will be stored here
new File(containerDirectory + "/root").mkdirs(); // The root directory of the overlay mount
new File(containerDirectory+"/work").mkdirs(); // The work directory of the overlay mount
}
/*
* Start a container
*
* @param getCommand: If true, return the command to run the container
*
* @return: The command to run the container. If getCommand is false, return null
*/
public String startContainer(boolean getCommand) {
String containerDirectory = dataStore.getContainerPath(this.containerName);
List<String> content = null;
try {
content = Files.readAllLines(Paths.get(this.dataStore.getPath() + "/" + this.containerImage + "/" + this.containerTag + "/layers"));
} catch (IOException e) {
throw new RuntimeException(e);
}
assert content != null; // assert my beloved
// We parse the layers file to get the layers of the image
List<String> layers = new ArrayList<>();
for (String line : content) {
layers.add(this.dataStore.getPath() + "/blobs/" + line.replace("sha256:", ""));
}
assert layers.size() > 0;
SysUtils sysUtils = new SysUtils();
String[] diffs = layers.toArray(new String[0]);
// Depending on getCommand we either directly mount the layers or return the command to mount the layers
return sysUtils.overlayMount(diffs, containerDirectory + "/containerOverlay", containerDirectory + "/root", containerDirectory + "/work", !getCommand);
}
/*
* Run a command in a container
*/
public void runCommand() {
String containerDirectory = dataStore.getContainerPath(this.containerName);
String dataStorePath = dataStore.getPath();
File configPath = new File(dataStorePath + "/" + this.containerImage + "/" + this.containerTag + "/config"); // Path to the config file of the image
String content = null;
try {
content = Files.readAllLines(Paths.get(configPath.getAbsolutePath())).toString();
} catch (IOException e) {
throw new RuntimeException(e);
}
ObjectMapper mapper = new ObjectMapper();
List<String> env = new ArrayList<>();
String cmd = null;
String hostname = null;
try {
JsonNode config = mapper.readTree(content.toString()).get(0).get("config");
config.get("Env").forEach((JsonNode envVar) -> { // Get the environment variables specified in the config file
env.add(envVar.asText());
});
cmd = config.get("Cmd").get(0).asText(); // Get the command specified in the config file
hostname = config.get("Hostname").asText(); // Get the hostname specified in the config file
} catch (JsonProcessingException e) {
throw new RuntimeException(e);
}
// why would these be null? I don't know, but I won't bother handling this better
assert hostname != null;
assert cmd != null;
List<String> bwrapCommand = new ArrayList<>();
for(String envVar : env) {
bwrapCommand.add("--setenv "+envVar.split("=")[0]+" "+envVar.split("=")[1]); // Create the flags for bwrap to set the environment variables
}
bwrapCommand.add("--bind "+containerDirectory+"/root / --chdir /"); // Bind the root to / inside the bwrap namespace
bwrapCommand.add("--share-net"); // Share the network namespace
bwrapCommand.add("--unshare-uts --hostname "+ (!hostname.isBlank() ? hostname : this.containerName+"-"+this.containerImage)); // Unshare the UTS namespace and set the hostname
bwrapCommand.add("/bin/sh -c '"+(this.containerCommand != null ? this.containerCommand : cmd)+"'"); // Run the command specified in the config file or the command specified in the constructor
SysUtils sysUtils = new SysUtils();
String bwrapCMD = sysUtils.execInBwrap(bwrapCommand.toArray(new String[0]), false);
String mountCMD = startContainer(true);
String CMD = "unshare --user --map-root-user --mount bash -c \""+mountCMD+";"+bwrapCMD+"\""; // I am starting to realize that this project was not a good idea
ProcessBuilder pb = new ProcessBuilder("bash", "-c", CMD);
pb.inheritIO();
try {
Process p = pb.start();
p.waitFor();
} catch (IOException | InterruptedException e) {
throw new RuntimeException(e);
}
}
/*
* Delete a container
*/
public void deleteContainer() {
String containerDirectory = dataStore.getContainerPath(this.containerName);
try {
Files.delete(Paths.get(containerDirectory + "/containerOverlay"));
Files.delete(Paths.get(containerDirectory + "/root"));
Files.delete(Paths.get(containerDirectory + "/work"));
Files.delete(Paths.get(containerDirectory));
} catch (IOException e) {
throw new RuntimeException(e);
}
dataStore.deleteContainerFromDatabase(this.containerName);
}
}
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