Java tutorial
package io.fathom.cloud.compute.services; import io.fathom.cloud.compute.scheduler.SchedulerHost; import io.fathom.cloud.protobuf.CloudModel.HostData; import io.fathom.cloud.protobuf.CloudModel.HostGroupData; import io.fathom.cloud.protobuf.CloudModel.HostGroupSecretData; import io.fathom.cloud.protobuf.CloudModel.HostGroupType; import java.io.IOException; import java.net.URI; import java.text.ParseException; import java.util.Date; import com.amazonaws.AmazonClientException; import com.amazonaws.auth.AWSCredentials; import com.amazonaws.auth.BasicAWSCredentials; import com.amazonaws.auth.BasicSessionCredentials; import com.amazonaws.auth.InstanceProfileCredentialsProvider; import com.amazonaws.internal.EC2MetadataClient; import com.amazonaws.services.ec2.AmazonEC2Client; import com.amazonaws.util.DateUtils; import com.amazonaws.util.json.JSONException; import com.amazonaws.util.json.JSONObject; import com.google.common.base.Strings; public class Ec2DatacenterManager implements DatacenterManager { final HostGroupData hostGroupData; AmazonEC2Client ec2Client; public Ec2DatacenterManager(HostGroupData hostGroupData, HostGroupSecretData secretData) { this.hostGroupData = hostGroupData; if (hostGroupData.getHostGroupType() != HostGroupType.HOST_GROUP_TYPE_AMAZON_EC2) { throw new IllegalStateException(); } if (secretData.hasUsername()) { String accessKey = secretData.getUsername(); String secretKey = secretData.getPassword(); AWSCredentials awsCredentials = new BasicAWSCredentials(accessKey, secretKey); ec2Client = new AmazonEC2Client(awsCredentials); } } public AmazonEC2Client getEc2Client(SchedulerHost host) { if (this.ec2Client != null) { return this.ec2Client; } CredentialsProvider credentialsProvider = new CredentialsProvider(host); AmazonEC2Client ec2Client = new AmazonEC2Client(credentialsProvider); return ec2Client; } /** * Borrowed from AWS SDK (Apache licensed) * InstanceProfileCredentialsProvider */ class CredentialsProvider extends InstanceProfileCredentialsProvider { private final SchedulerHost host; protected volatile AWSCredentials credentials; protected volatile Date credentialsExpiration; public CredentialsProvider(SchedulerHost host) { this.host = host; } @Override public AWSCredentials getCredentials() { if (needsToLoadCredentials()) { loadCredentials(); } if (expired()) { throw new AmazonClientException( "The credentials received from the Amazon EC2 metadata service have expired"); } return credentials; } private boolean expired() { if (credentialsExpiration != null) { if (credentialsExpiration.getTime() < System.currentTimeMillis()) { return true; } } return false; } private synchronized void loadCredentials() { if (needsToLoadCredentials()) { try { // String credentialsResponse = new // EC2MetadataClient().getDefaultCredentials(); String credentialsResponse = getDefaultCredentials(); JSONObject jsonObject = new JSONObject(credentialsResponse); if (jsonObject.has("Token")) { credentials = new BasicSessionCredentials(jsonObject.getString("AccessKeyId"), jsonObject.getString("SecretAccessKey"), jsonObject.getString("Token")); } else { credentials = new BasicAWSCredentials(jsonObject.getString("AccessKeyId"), jsonObject.getString("SecretAccessKey")); } if (jsonObject.has("Expiration")) { /* * TODO: The expiration string comes in a different * format than what we deal with in other parts of the * SDK, so we have to convert it to the ISO8601 syntax * we expect. */ String expiration = jsonObject.getString("Expiration"); expiration = expiration.replaceAll("\\+0000$", "Z"); credentialsExpiration = new DateUtils().parseIso8601Date(expiration); } } catch (IOException e) { throw new AmazonClientException("Unable to load credentials from Amazon EC2 metadata service", e); } catch (JSONException e) { throw new AmazonClientException("Unable to parse credentials from Amazon EC2 metadata service", e); } catch (ParseException e) { throw new AmazonClientException( "Unable to parse credentials expiration date from Amazon EC2 metadata service", e); } } } private String getDefaultCredentials() throws IOException { String securityCredentialsList = readResource(EC2MetadataClient.SECURITY_CREDENTIALS_RESOURCE); securityCredentialsList = securityCredentialsList.trim(); String[] securityCredentials = securityCredentialsList.split("\n"); if (securityCredentials.length == 0) { return null; } String securityCredentialsName = securityCredentials[0]; return readResource(EC2MetadataClient.SECURITY_CREDENTIALS_RESOURCE + securityCredentialsName); } private String readResource(String resourcePath) throws IOException { String url = "http://169.254.169.254" + resourcePath; URI uri = URI.create(url); return host.fetchUrl(uri); } } public String findHost(SchedulerHost host) { HostData hostData = host.getHostData(); if (hostData.getHostGroup() != hostGroupData.getId()) { throw new IllegalStateException(); } String providerId = hostData.getProviderId(); if (Strings.isNullOrEmpty(providerId)) { throw new IllegalStateException(); } return providerId; } }