elastic-apm-node/lib/apm-client/http-apm-client/container-info.js

The official Elastic APM agent for Node.js

/*
 * Copyright Elasticsearch B.V. and other contributors where applicable.
 * Licensed under the BSD 2-Clause License; you may not use this file except in
 * compliance with the BSD 2-Clause License.
 */

'use strict';

const fs = require('fs');

const uuidSource =
  '[0-9a-f]{8}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{12}';
const containerSource = '[0-9a-f]{64}';
const taskSource = '[0-9a-f]{32}';
const awsEcsSource = '[0-9a-f]{32}-[0-9]{1,10}';

const lineReg = /^(\d+):([^:]*):(.+)$/;
const podReg = new RegExp(`pod(${uuidSource})(?:.slice)?$`);
const containerReg = new RegExp(
  `(${uuidSource}|${containerSource})(?:.scope)?$`,
);
const taskReg = new RegExp(`^/ecs/(${taskSource})/.*$`);

let ecsMetadata;
resetEcsMetadata(process.env.ECS_CONTAINER_METADATA_FILE);

function resetEcsMetadata(file) {
  ecsMetadata = ecsMetadataSync(file);
}

function parseLine(line) {
  const [id, groups, path] = (line.match(lineReg) || []).slice(1);
  const data = { id, groups, path };
  const parts = path.split('/');
  const basename = parts.pop();
  const controllers = groups.split(',');
  if (controllers) data.controllers = controllers;

  const containerId = (basename.match(containerReg) || [])[1];
  if (containerId) data.containerId = containerId;

  const podId = (parts.pop().match(podReg) || [])[1];
  if (podId) data.podId = podId.replace(/_/g, '-');

  const taskId = (path.match(taskReg) || [])[1];
  if (taskId) data.taskId = taskId;

  // if we reach the end and there's still no conatinerId match
  // and there's not an ECS metadata file, try the ECS regular
  // expression in order to get a container id in fargate
  if (!containerId && !ecsMetadata) {
    if (basename.match(awsEcsSource)) {
      data.containerId = basename;
    }
  }
  return data;
}

function parse(contents) {
  const data = {
    entries: [],
  };

  for (let line of contents.split('\n')) {
    line = line.trim();
    if (line) {
      const lineData = parseLine(line);
      data.entries.push(lineData);
      if (lineData.containerId) {
        data.containerId = lineData.containerId;
      }
      if (lineData.podId) {
        data.podId = lineData.podId;
      }
      if (lineData.taskId) {
        data.taskId = lineData.taskId;
        if (ecsMetadata) {
          data.containerId = ecsMetadata.ContainerID;
        }
      }
    }
  }

  return data;
}

function containerInfo(pid = 'self') {
  return new Promise((resolve) => {
    fs.readFile(`/proc/${pid}/cgroup`, (err, data) => {
      resolve(err ? undefined : parse(data.toString()));
    });
  });
}

function containerInfoSync(pid = 'self') {
  try {
    const data = fs.readFileSync(`/proc/${pid}/cgroup`);
    return parse(data.toString());
  } catch (err) {}
}

function ecsMetadataSync(ecsMetadataFile) {
  try {
    return ecsMetadataFile && JSON.parse(fs.readFileSync(ecsMetadataFile));
  } catch (err) {}
}

module.exports = containerInfo;
containerInfo.sync = containerInfoSync;
containerInfo.parse = parse;
containerInfo.resetEcsMetadata = resetEcsMetadata; // Exported for testing-only.