Awsome Doctor

A browser-based tool that helps you to trouble shoot your AWS environment.

Features

• YAML format workflow file.
  • You don't need to have web/frontend skills to create a new workflow.
  • By using the built-in editor, you don't need to learn YAML. All you need is programming with JavaScript.
• Markdown format output.
  • External links, titles, styled fonts, codes, etc.
• Custom HTTP request powered by axios.
• Modularization.

Write a Workflow

File Structure

The built-in editor is preferred to generate or edit workflow files, so you don't have to learn how to write YAML files.

A workflow consists of those parts in a yaml file:

title: Can't ping EC2 instance from the Internet.

description: "" # markdown

# you can define data that you need to use across steps
# or accept user input
data:
  instanceId: "" # format: `key: default value`

input:
  - label: Instance ID
    placeholder: i-01234567891234567
    # this input will be stored in the data named `instanceId`
    store: instanceId
    # currently supported input type: text/password/file
    type: text

steps:
  - name: Instance status check.
    js: | # multiline string
      $.ok = "OK"

Eval the Code

The js code in steps is a JavaScript async function body wrapped by a try-catch block. The content will be run by:

try {
  await eval(`
    (async () => {
      ${step.js}
    })()
  `);
} catch (e) {
  $.err = e;
}

Which means you can:

• Use return to stop running the current step.
• Use await inside the code block.
• Throw exceptions, or ignore exceptions if you don't plan to handle them.

Examples:

// call async function
// and ignore exceptions since we don't plan to handle them
let res = await $.axios.get("https://example.com");

if (!res.data) return; // stop running the current step

// process res
// ...

Context

You can access a context variable $ in your JavaScript code. The context variable contains the following members:

let $ = {
  AWS, // aws sdk v2, see https://github.com/aws/aws-sdk-js
  aws, // aws helper, see examples below

  // The data you defined in your workflow file.
  data: {},

  // Json path, see https://github.com/dchester/jsonpath
  jp,

  // js-yaml, see https://github.com/nodeca/js-yaml
  yaml,

  // HTTP client, see https://github.com/axios/axios
  axios,

  // GET a file from CDN then eval
  import(url) {},

  // output, see the document below
  err: "",
  info: "",
  ok: "",
  panic(msg) {},
  done(msg) {},

  // stop executing remaining steps
  stop: false,
};

Examples:

// call AWS
let ec2 = new $.AWS.EC2();
let res = await ec2
  .describeInstanceStatus({
    InstanceIds: [$.data.instanceId],
  })
  .promise();

// call AWS with helper
let res = await $.aws.ec2.describeInstanceStatus({
  InstanceIds: [$.data.instanceId],
});

// wrap existing AWS client using helper
let _ec2 = new $.AWS.EC2(config);
let ec2 = $.aws.wrap(_ec2);
let res = await ec2.describeInstanceStatus({
  InstanceIds: [$.data.instanceId],
});

// http request
let res = await $.axios.get("https://examples.com");

// dump object as YAML
$.yaml.dump(res);

// using json path
let publicIps = $.jp.query(res, "$..PrivateIpAddresses..PublicIp");

// output
$.err += "error";
$.info += "info";
$.ok += "ok";

// stop workflow
$.stop = true;

Output

• ok means users don't need to check this step's output.
• info means users need to check the output manually.
• err means there must be something wrong.

The output is rendered using result.err || result.ok || result.info, which means if your $.err is not empty, the output will not contain $.ok and $.info.

The output is rendered as Markdown if your output starts with /md\n:

// use multiline string
$.ok = `/md
# title

## subtitle

> Ref.

**Bold**, *italic*, \`inline code\`, [external link](https://aws.amazon.com).

\`\`\`js
// code block
let a = 1;
console.log(123);
\`\`\`
`;

// use normal string
$.ok = "/md\n# Markdown";

$.panic(msg)/$.done(msg) is a syntactic sugar for $.err = msg; return;/$.ok = msg; return;. $.panic/$.done will throw an exception with class StepStopper, which will stop the current step and be handled by the workflow executor properly.

With $.panic/$.done, you can also stop your workflow in nested functions, e.g.:

[0].map((e) => {
  $.panic("msg");
});

Modularization

External workflows might be dangerous since your AK/SK can be retrieved through await $.AWS.config.credentials.

There are some approaches to reuse external or 3rd party code:

// use helper, which will GET a file and eval it
await $.import("https://unpkg.com/:package@:version/:file");

// use http request to retrieve 3rd party code
let res = await $.axios.get("https://unpkg.com/:package@:version/:file");
eval(res.data);

// use awsome-doctor-utils
await $.import("https://unpkg.com/awsome-doctor-utils/dist/bundle.js");

// use steps from other workflow
let res = await $.axios.get("https://example.com/some-workflow.yml");
let workflow = $.yaml.load(res.data);
await eval(`
  (async () => {
    ${workflow.steps[0]}
  })()
`);

Multi-region or Multi-account

// retrieve current credentials
let credentials = $.AWS.config.credentials;

// construct config with new credentials or region code
let config = {
  credentials,
  region: "us-east-2",
};

// create your own service client
let ec2 = new $.AWS.EC2(config);

Related Projects

• awsome-doctor
• awsome-doctor-view
• awsome-doctor-core
• awsome-doctor-utils