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/*
*
* * Copyright 2020 New Relic Corporation. All rights reserved.
* * SPDX-License-Identifier: Apache-2.0
*
*/
package com.newrelic.agent.utilization;
import com.google.common.annotations.VisibleForTesting;
import com.newrelic.agent.Agent;
import com.newrelic.agent.config.internal.SystemEnvironmentFacade;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.text.MessageFormat;
import java.util.logging.Level;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/*
* Grabs the docker container id.
* For newer Linux systems running cgroup v2, this is taken from /proc/self/mountinfo. The line should look like:
*
* 594 576 254:1 /docker/containers/f37a7e4d17017e7bf994656b19ca4360c6cdc4951c86700a464101d0d9ce97ef/hosts /etc/hosts rw,relatime - ext4 /dev/vda1 rw,discard
*
* For older Linux systems running cgroup v1, this is taken from /proc/self/cgroup. The line should look like:
*
* +4:cpu:/docker/3ccfa00432798ff38f85839de1e396f771b4acbe9f4ddea0a761c39b9790a782
*
* We should grab the "cpu" line. The long id number is the number we want.
*
* For AWS ECS (fargate and non-fargate) we check the metadata returned from the URL defined in either the
* v3 or v4 metadata URL. These checks are only made if the metadata URL(s) are present in the target env variables.
* The docker id returned in the metadata JSON response is a 32-digit hex followed by a 10-digit number in the "DockerId" key.
*
* In either case, this is the full docker id, not the short id that appears when you run a "docker ps".
*/
public class DockerData {
private static final String FILE_WITH_CONTAINER_ID_V1 = "/proc/self/cgroup";
private static final String FILE_WITH_CONTAINER_ID_V2 = "/proc/self/mountinfo";
private static final String CPU = "cpu";
private static final String AWS_ECS_METADATA_UNVERSIONED_ENV_VAR = "ECS_CONTAINER_METADATA_URI";
private static final String AWS_ECS_METADATA_V4_ENV_VAR = "ECS_CONTAINER_METADATA_URI_V4";
private static final String FARGATE_DOCKER_ID_KEY = "DockerId";
private static final Pattern VALID_CONTAINER_ID = Pattern.compile("^[0-9a-f]{64}$");
private static final Pattern DOCKER_CONTAINER_STRING_V1 = Pattern.compile("^.*[^0-9a-f]+([0-9a-f]{64,}).*");
private static final Pattern DOCKER_CONTAINER_STRING_V2 = Pattern.compile(".*/docker/containers/([0-9a-f]{64,}).*");
public String getDockerContainerIdForEcsFargate(boolean isLinux) {
if (isLinux) {
String result;
// Try v4 ESC Fargate metadata call, then fallback to the un-versioned call
String fargateUrl = null;
try {
fargateUrl = System.getenv(AWS_ECS_METADATA_V4_ENV_VAR);
if (fargateUrl != null) {
Agent.LOG.log(Level.INFO, "Attempting to fetch ECS Fargate container id from URL (v4): {0}", fargateUrl);
result = retrieveDockerIdFromFargateMetadata(new AwsFargateMetadataFetcher(fargateUrl));
if (result != null) {
return result;
}
}
fargateUrl = System.getenv(AWS_ECS_METADATA_UNVERSIONED_ENV_VAR);
if (fargateUrl != null) {
Agent.LOG.log(Level.INFO, "Attempting to fetch ECS Fargate container id from URL (unversioned): {0}", fargateUrl);
return retrieveDockerIdFromFargateMetadata(new AwsFargateMetadataFetcher(fargateUrl));
}
} catch (MalformedURLException e) {
Agent.LOG.log(Level.FINEST, "Invalid AWS Fargate metadata URL: {0}", fargateUrl);
}
}
return null;
}
public String getDockerContainerIdFromCGroups(boolean isLinux) {
if (isLinux) {
String result;
//try to get the container id from the v2 location
File containerIdFileV2 = new File(FILE_WITH_CONTAINER_ID_V2);
result = getDockerIdFromFile(containerIdFileV2, CGroup.V2);
if (result != null) {
return result;
}
//try to get container id from the v1 location
File containerIdFileV1 = new File(FILE_WITH_CONTAINER_ID_V1);
result = getDockerIdFromFile(containerIdFileV1, CGroup.V1);
if (result != null) {
return result;
}
}
return null;
}
String getDockerIdFromFile(File mountInfoFile, CGroup cgroup) {
if (mountInfoFile.exists() && mountInfoFile.canRead()) {
try {
return readFile(new FileReader(mountInfoFile), cgroup);
} catch (FileNotFoundException e) {
}
}
return null;
}
String readFile(Reader reader, CGroup cgroup) {
try (BufferedReader bReader = new BufferedReader(reader)) {
String line;
StringBuilder resultGoesHere = new StringBuilder();
while ((line = bReader.readLine()) != null) {
if (checkLineAndGetResult(line, resultGoesHere, cgroup)) {
String value = resultGoesHere.toString().trim();
if (isInvalidDockerValue(value)) {
Agent.LOG.log(Level.WARNING, MessageFormat.format("Failed to validate Docker value {0}", value));
return null;
}
return value;
}
}
} catch (Throwable e) {
Agent.LOG.log(Level.FINEST, e, "Exception occurred when reading docker file.");
}
return null;
}
boolean checkLineAndGetResult(String line, StringBuilder resultGoesHere, CGroup cgroup) {
if (cgroup == CGroup.V1) {
return checkLineAndGetResultV1(line, resultGoesHere);
} else if (cgroup == CGroup.V2) {
return checkLineAndGetResultV2(line, resultGoesHere);
}
return false;
}
private boolean checkLineAndGetResultV1(String line, StringBuilder resultGoesHere) {
String[] parts = line.split(":");
if (parts.length == 3 && validCpuLine(parts[1])) {
String mayContainId = parts[2];
if (checkAndGetMatch(DOCKER_CONTAINER_STRING_V1, resultGoesHere, mayContainId)) {
return true;
} else if (!mayContainId.equals("/")) {
Agent.LOG.log(Level.FINE, "Docker Data: Ignoring unrecognized cgroup ID format: {0}", mayContainId);
}
}
return false;
}
private boolean checkLineAndGetResultV2(String line, StringBuilder resultGoesHere) {
String[] parts = line.split(" ");
if (parts.length >= 4 ) {
String mayContainId = parts[3];
if (checkAndGetMatch(DOCKER_CONTAINER_STRING_V2, resultGoesHere, mayContainId)) {
return true;
}
}
return false;
}
boolean isInvalidDockerValue(String value) {
/*
* Value should be exactly 64 characters.
*
* Value is expected to include only [0-9a-f]
*/
return (value == null) || (!VALID_CONTAINER_ID.matcher(value).matches());
}
private boolean validCpuLine(String segment) {
if (segment != null) {
String[] parts = segment.split(",");
for (String current : parts) {
if (current.equals(CPU)) {
return true;
}
}
}
return false;
}
/*
* Get the match for the capture group of a single-capture-group regex expression.
*/
private boolean checkAndGetMatch(Pattern p, StringBuilder result, String segment) {
Matcher m = p.matcher(segment);
if (m.matches() && m.groupCount() == 1) {
result.append(m.group(1));
return true;
}
return false;
}
@VisibleForTesting
String retrieveDockerIdFromFargateMetadata(AwsFargateMetadataFetcher awsFargateMetadataFetcher) {
String dockerId = null;
StringBuilder jsonBlob = new StringBuilder();
try {
try (BufferedReader reader = new BufferedReader(new InputStreamReader(awsFargateMetadataFetcher.openStream()))) {
String line;
while ((line = reader.readLine()) != null) {
jsonBlob.append(line);
}
}
JSONObject jsonObject = (JSONObject) new JSONParser().parse(jsonBlob.toString());
dockerId = (String) jsonObject.get(FARGATE_DOCKER_ID_KEY);
Agent.LOG.log(Level.INFO, "ECS Fargate container id: {0} ", dockerId);
} catch (IOException e) {
Agent.LOG.log(Level.WARNING, "Error opening input stream retrieving AWS Fargate metadata");
} catch (ParseException e) {
Agent.LOG.log(Level.WARNING, "Error parsing JSON blob for AWS Fargate metadata");
}
return dockerId;
}
}
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