io.fabric8.maven.docker.access.DockerConnectionDetector Maven / Gradle / Ivy
package io.fabric8.maven.docker.access;
import java.io.*;
import java.util.*;
import io.fabric8.maven.docker.access.util.LocalSocketUtil;
import io.fabric8.maven.docker.util.*;
/**
* Detector for determining the Docker access mechanism
*/
public class DockerConnectionDetector {
final List dockerHostProviders;
public DockerConnectionDetector(List externalProviders) {
dockerHostProviders = new ArrayList<>();
dockerHostProviders.addAll(getDefaultEnvProviders());
if (externalProviders != null) {
dockerHostProviders.addAll(externalProviders);
}
Collections.sort(dockerHostProviders,new DockerHostProvider.Comparator());
}
private Collection getDefaultEnvProviders() {
return Arrays.asList(new EnvDockerHostProvider(),
new UnixSocketDockerHostProvider(),
new WindowsPipeDockerHostProvider());
}
/**
* Provider of environment variables like 'DOCKER_HOST'
*/
public interface DockerHostProvider {
/**
* Get value of the docker host as detected by this provider. Return null if it couldn't be detected.
*
* @return the docker host parameter or null
* @param certPath
*/
ConnectionParameter getConnectionParameter(String certPath) throws IOException;
/**
* Get the priority of the env provider. A priority of -1 means, this is a 'fallback' called
* as last resort.
*
* @return priority, the higher, the earlier the provider is called.
* The highest priority of internal providers are not larger than 100.
*/
int getPriority();
class Comparator implements java.util.Comparator {
@Override
public int compare(DockerHostProvider o1, DockerHostProvider o2) {
return o2.getPriority() - o1.getPriority();
}
}
}
/**
* Get the docker host url.
*
* - From <dockerHost> configuration
* - From <machine> configuration
* - From DOCKER_HOST environment variable
* - Default to /var/run/docker.sock
*
* @param dockerHost The dockerHost configuration setting
* @return The docker host url
* @throws IOException when URL handling fails
*/
public ConnectionParameter detectConnectionParameter(String dockerHost, String certPath) throws IOException {
if (dockerHost != null) {
return new ConnectionParameter(dockerHost, certPath);
}
for (DockerHostProvider provider : dockerHostProviders) {
ConnectionParameter value = provider.getConnectionParameter(certPath);
if (value != null) {
return value;
}
}
throw new IllegalArgumentException("No given, no DOCKER_HOST environment variable, " +
"no read/writable '/var/run/docker.sock' or '//./pipe/docker_engine' " +
"and no external provider like Docker machine configured");
}
// ====================================================================================================
// Lookup from the enviroment
class EnvDockerHostProvider implements DockerHostProvider {
@Override
public ConnectionParameter getConnectionParameter(String certPath) throws IOException {
String connect = System.getenv("DOCKER_HOST");
return connect != null ? new ConnectionParameter(connect, certPath) : null;
}
@Override
public int getPriority() {
return 100;
}
}
// Check for a unix socket
class UnixSocketDockerHostProvider implements DockerHostProvider {
@Override
public ConnectionParameter getConnectionParameter(String certPath) throws IOException {
File unixSocket = new File("/var/run/docker.sock");
if (unixSocket.exists() && unixSocket.canRead() && unixSocket.canWrite() && LocalSocketUtil.canConnectUnixSocket(unixSocket)) {
return new ConnectionParameter("unix:///var/run/docker.sock", certPath);
} else {
return null;
}
}
@Override
public int getPriority() {
return 55;
}
}
// Check for a windows pipe
class WindowsPipeDockerHostProvider implements DockerHostProvider {
@Override
public ConnectionParameter getConnectionParameter(String certPath) throws IOException {
File windowsPipe = new File("//./pipe/docker_engine");
if (windowsPipe.exists()) {
return new ConnectionParameter("npipe:////./pipe/docker_engine", certPath);
} else {
return null;
}
}
@Override
public int getPriority() {
return 50;
}
}
public static class ConnectionParameter {
private final String url;
private String certPath;
public ConnectionParameter(String url, String certPath) throws IOException {
this.url = url != null ? EnvUtil.convertTcpToHttpUrl(url) : null;
initCertPath(certPath);
}
public String getUrl() {
return url;
}
public String getCertPath() {
return certPath;
}
/**
* Get the docker certificate location
*
* - From <certPath> a given cert config argument
* - From DOCKER_CERT_PATH environment variable
* - Default to ${user.home}/.docker
*
* @param certPath the configured certification path which is used directly if set
*/
private void initCertPath(String certPath) throws IOException {
this.certPath = certPath != null ? certPath : System.getenv("DOCKER_CERT_PATH");
// Try default locations as last resort
if (this.certPath == null) {
File dockerHome = new File(System.getProperty("user.home") + "/.docker");
if (dockerHome.isDirectory()) {
String[] entries = dockerHome.list(SuffixFileFilter.PEM_FILTER);
if (entries == null) {
throw new IOException("Can not read directory " + dockerHome + ". Please check file permissions.");
}
if (entries.length > 0) {
this.certPath = dockerHome.getAbsolutePath();
}
}
}
}
}
}