@pact-foundation/pact-core

ℹ️ Usage notice
This is a core library, designed for use in the bowels of another package. Unless you are wanting to develop tools for the pact ecosystem, you almost certainly want to install @pact-foundation/pact instead

Pact-JS Core

A wrapper for the Pact CLI Tools.

• Pact-JS Core
  • Installation
    • Do Not Track
  • Which Library/Package should I use?
  • Usage
  • Documentation
    • Set Log Level
    • Mock Servers
      • Create Mock Server
      • List Mock Servers
      • Remove All Mock Servers
      • Start a Mock Server
      • Stop a Mock server
      • Delete a Mock server
      • Check if a Mock server is running
      • Mock Server Events
    • Provider Verification
    • Pact Broker Publishing
    • Pact Broker Deployment Check
    • Stub Servers
      • Create Stub Server
    • Message Pacts
      • Create Message Pacts
        • Example
  • CLI Tools
  • Windows Issues
    • Enable Long Paths
  • Contributing
  • Testing
  • Questions?

Installation

npm install @pact-foundation/pact-core --save-dev

Do Not Track

In order to get better statistics as to who is using Pact, we have an anonymous tracking event that triggers when Pact installs for the first time. To respect your privacy, anyone can turn it off by simply adding a 'do not track' flag within their package.json file:

{
 "name": "some-project",
 ...
 "config": {
  "pact_do_not_track": true
 },
 ...
}

Which Library/Package should I use?

TL;DR - you almost always want Pact JS.

Purpose	Library	Comments
Synchronous / HTTP APIs	Pact JS
Asynchronous APIs	Pact JS
Node.js	Pact JS
Browser testing	Pact Web	You probably still want Pact JS. See Using Pact in non-Node environments *
Isomorphic testing	Pact Web	You probably still want Pact JS. See Using Pact in non-Node environments *
Publishing to Pact Broker	Pact Node	Included in Pact JS distribution

* The "I need to run it in the browser" question comes up occasionally. The question is this - for your JS code to be able to make a call to another API, is this dependent on browser-specific code? In most cases, people use tools like React/Angular which have libraries that work on the server and client side, in which case, these tests don't need to run in a browser and could instead be executed in a Node.js environment.

Usage

Simply require the library and call the create function to start the mock service

var pact = require("@pact-foundation/pact-core");
var server = pact.createServer({ port: 9999 });
server.start().then(function() {
 // Do your testing/development here
});

Or if you're using Typescript instead of plain old Javascript

import pact from "@pact-foundation/pact-core";
const server = pact.createServer({ port: 9999 });
server.start().then(() => {
 // Do your testing/development here
});

Or you can also use the CLI

$# pact mock --port 9999

To see the list commands possible with the CLI, simply ask for help $# pact --help

Documentation

Set Log Level

var pact = require("@pact-foundation/pact-core");
pact.logLevel("debug");

or you can set it via an environment variable

LOG_LEVEL=debug

Mock Servers

Mock servers are used by Pact to record interactions and create pact contracts.

Create Mock Server

var pact = require('@pact-foundation/pact-core');
var server = pact.createServer({
 ...
});

Options:

Parameter	Required?	Type	Description
port	false	number	Port number that the server runs on, defaults to random available port
host	false	string	Host on which to bind the server on, defaults to 'localhost'. Supports '0.0.0.0' to bind on all IPv4 addresses on the local machine.
log	false	string	File to log output on relative to current working directory, defaults to none
logLevel	false	LogLevel (string)	Log level to pass to the pact core. One of "DEBUG", "ERROR", "WARN", "INFO", can be set by LOG_LEVEL env var
ssl	false	boolean	Create a self-signed SSL cert to run the server over HTTPS , defaults to false
sslcert	false	string	Path to a custom self-signed SSL cert file, 'ssl' option must be set to true to use this option, defaults to none
sslkey	false	string	Path a custom key and self-signed SSL cert key file, 'ssl' option must be set to true to use this, defaults to none
cors	false	boolean	Allow CORS OPTION requests to be accepted, defaults to 'false'
dir	false	string	Directory to write the pact contracts relative to the current working directory, defaults to none
spec	false	number	The pact specification version to use when writing pact contracts, defaults to '1'
consumer	false	string	The name of the consumer to be written to the pact contracts, defaults to none
provider	false	string	The name of the provider to be written to the pact contracts, defaults to none
pactFileWriteMode	false	overwrite OR update OR merge	Control how the pact file is created. Defaults to "overwrite"
format	false	json OR xml	Format to write the results as, either in JSON or XML, defaults to JSON
out	false	string	Write output to a file instead of returning it in the promise, defaults to none
timeout	false	number	How long to wait for the mock server to start up (in milliseconds). Defaults to 30000 (30 seconds)

List Mock Servers

If you ever need to see which servers are currently created.

var pact = require("@pact-foundation/pact-core");
var servers = pact.listServers();
console.log(JSON.stringify(servers));

Remove All Mock Servers

Remove all servers once you're done with them in one fell swoop.

var pact = require("@pact-foundation/pact-core");
pact.removeAllServers();

Start a Mock Server

Start the current server.

var pact = require("@pact-foundation/pact-core");
pact.createServer()
 .start()
 .then(function() {
  // Do something after it started
 });

Stop a Mock server

Stop the current server.

var pact = require("@pact-foundation/pact-core");
pact.createServer()
 .stop()
 .then(function() {
  // Do something after it stopped
 });

Delete a Mock server

Stop the current server and deletes it from the list.

var pact = require("@pact-foundation/pact-core");
pact.createServer()
 .delete()
 .then(function() {
  // Do something after it was killed
 });

Check if a Mock server is running

var pact = require("@pact-foundation/pact-core");
pact.createServer().running;

Mock Server Events

There's 3 different events available, 'start', 'stop' and 'delete'. They can be listened to the same way as an EventEmitter.

var pact = require("@pact-foundation/pact-core");
var server = pact.createServer();
server.on("start", function() {
 console.log("started");
});
server.on("stop", function() {
 console.log("stopped");
});
server.on("delete", function() {
 console.log("deleted");
});

Provider Verification

Read more about Verify Pacts.

var pact = require('@pact-foundation/pact-core');

pact.verifyPacts({
 ...
});

Options:

Parameter	Required?	Type	Description
providerBaseUrl	true	string	Running API provider host endpoint.
pactBrokerUrl	false	string	Base URL of the Pact Broker from which to retrieve the pacts. Required if pactUrls not given.
provider	false	string	Name of the provider if fetching from a Broker
consumerVersionSelectors	false	ConsumerVersionSelector|array	Use Selectors to is a way we specify which pacticipants and versions we want to use when configuring verifications.
consumerVersionTags	false	string|array	Retrieve the latest pacts with given tag(s)
providerVersionTags	false	string|array	Tag(s) to apply to the provider application
includeWipPactsSince	false	string	Includes pact marked as WIP since this date. String in the format %Y-%m-%d or %Y-%m-%dT%H:%M:%S.000%:z
pactUrls	false	array	Array of local pact file paths or HTTP-based URLs. Required if not using a Pact Broker.
providerStatesSetupUrl	false	string	URL to send PUT requests to setup a given provider state
pactBrokerUsername	false	string	Username for Pact Broker basic authentication
pactBrokerPassword	false	string	Password for Pact Broker basic authentication
pactBrokerToken	false	string	Bearer token for Pact Broker authentication
publishVerificationResult	false	boolean	Publish verification result to Broker (NOTE: you should only enable this during CI builds)
providerVersion	false	string	Provider version, required to publish verification result to Broker. Optional otherwise.
enablePending	false	boolean	Enable the pending pacts feature.
timeout	false	number	The duration in ms we should wait to confirm verification process was successful. Defaults to 30000.
logLevel	false	LogLevel (string)	Log level. One of "TRACE", "DEBUG", "ERROR", "WARN", "INFO", can be set by LOG_LEVEL env var

The consumer version selector looks like this:

ConsumerVersionSelector {
  tag?: string;
  latest?: boolean;
  consumer?: string;
  deployedOrReleased?: boolean;
  deployed?: boolean; 
  released?: boolean; 
  environment?: string;
  fallbackTag?: string;
  branch?: string;
  mainBranch?: boolean;
  matchingBranch?: boolean;
}

See the Pact Broker documentation on selectors for more information.

Pact Broker Publishing

var pact = require('@pact-foundation/pact-core');
var opts = {
 ...
};

pact.publishPacts(opts).then(function () {
 // do something
});

Options:

Parameter	Required?	Type	Description
pactFilesOrDirs	true	array	Array of local Pact files or directories containing them. Required.
pactBroker	true	string	URL of the Pact Broker to publish pacts to. Required.
consumerVersion	true	string	A string containing a semver-style version e.g. 1.0.0. Required.
pactBrokerUsername	false	string	Username for Pact Broker basic authentication. Optional
pactBrokerPassword	false	string	Password for Pact Broker basic authentication. Optional
pactBrokerToken	false	string	Bearer token for Pact Broker authentication. Optional
tags	false	array	An array of Strings to tag the Pacts being published. Optional
branch	false	string	The branch to associate with the published pacts. Optional but recommended
autoDetectVersionProperties	false	boolean	Automatically detect the repository branch from known CI environment variables or git CLI. Supports Buildkite, Circle CI, Travis CI, GitHub Actions, Jenkins, Hudson, AppVeyor, GitLab, CodeShip, Bitbucket and Azure DevOps. Optional
buildUrl	false	string	The build URL that created the pact. Optional
verbose	false	boolean	Enables verbose output for underlying pact binary.

Pact Broker Deployment Check

var pact = require('@pact-foundation/pact-core');
var opts = {
 ...
};

pact.canDeploy(opts)
 .then(function (result) {
  // You can deploy this
    // If output is not specified or is json, result describes the result of the check.
    // If outout is 'table', it is the human readable string returned by the check
 })
 .catch(function(error) {
  // You can't deploy this
    // if output is not specified, or is json, error will be an object describing
    // the result of the check (if the check failed),
    // if output is 'table', then the error will be a string describing the output from the binary,

    // In both cases, `error` will be an Error object if something went wrong during the check.
 });

Options:

Parameter	Required?	Type	Description
pacticipants	true	[]objects	An array of version selectors in the form `{ name: String, latest?: string
			specify a tag, use the tagname with latest. Specify one of these per pacticipant
			that you want to deploy
pactBroker	true	string	URL of the Pact Broker to query about deployment. Required.
pactBrokerUsername	false	string	Username for Pact Broker basic authentication. Optional
pactBrokerPassword	false	string	Password for Pact Broker basic authentication. Optional
pactBrokerToken	false	string	Bearer token for Pact Broker authentication. Optional
output	false	json,table	Specify output to show, json or table. Optional, Defaults to json.
verbose	false	boolean	Enables verbose output for underlying pact binary.
retryWhileUnknown	false	number	The number of times to retry while there is an unknown verification result. Optional
retryInterval	false	number	The time between retries in seconds, use with retryWhileUnknown. Optional
to	false	string	The tag that you want to deploy to (eg, 'prod')

Stub Servers

Stub servers create runnable APIs from existing pact files.

The interface is comparable to the Mock Server API.

Create Stub Server

var pact = require('@pact-foundation/pact-core');
var server = pact.createStub({
 ...
});

Options:

Parameter	Required?	Type	Description
pactUrls	true	array	List of local Pact files to create the stub service from
port	false	number	Port number that the server runs on, defaults to random available port
host	false	string	Host on which to bind the server on, defaults to 'localhost'. Supports '0.0.0.0' to bind on all IPv4 addresses on the local machine.
log	false	string	File to log output on relative to current working directory, defaults to none
logLevel	false	LogLevel (string)	Log level to pass to the pact core. One of "DEBUG", "ERROR", "WARN", "INFO", can be set by LOG_LEVEL env var
ssl	false	boolean	Create a self-signed SSL cert to run the server over HTTPS , defaults to 'false'
sslcert	false	string	Path to a custom self-signed SSL cert file, 'ssl' option must be set to true to use this option. Defaults false
sslkey	false	string	Path a custom key and self-signed SSL cert key file, 'ssl' option must be set to true to use this option false. Defaults to none
cors	false	boolean	Allow CORS OPTION requests to be accepted, defaults to 'false'
timeout	false	number	How long to wait for the stub server to start up (in milliseconds). Defaults to 30000 (30 seconds)

Message Pacts

Create Message Pacts

var pact = require('@pact-foundation/pact-core');
var message = pact.createMessage({
 ...
});

Options:

Parameter	Required?	Type	Description
dir	true	string	Directory to write the pact contracts relative to the current working directory, defaults to none
consumer	true	string	The name of the consumer to be written to the pact contracts, defaults to none
provider	true	string	The name of the provider to be written to the pact contracts, defaults to none
pactFileWriteMode	false	`"overwrite"	"update"

Example

const messageFactory = messageFactory({
 consumer: "consumer",
 provider: "provider",
 dir: dirname(`${__filename}/pacts`),
 content: `{
  "description": "a test mesage",
  "content": {
   "name": "Mary"
  }
 }`
});

messageFactory.createMessage();

CLI Tools

This package also comes with the Pact Standalone Tools available as linked binaries in the standard NPM installation directory (e..g. ./node_modules/.bin).

This means you may call them direct from scripts in your package json, for example:

"scripts": {
  "pactPublish": "pact-broker publish ./pacts --consumer-app-version=$\(git describe\) --broker-base-url=$BROKER_BASE_URL --broker-username=$BROKER_USERNAME --broker-password=BROKER_PASSWORD"`
}
These are available in circumstances where `pact-core` has not yet implemented a feature or access via JavaScript APIs is not desirable. To run the binaries is as simple as the following:

*Example can-i-deploy check*:
```sh
./node_modules/.bin/pact-broker can-i-deploy --pacticipant "Banana Service" --broker-base-url https://test.pact.dius.com.au --latest --broker-username dXfltyFMgNOFZAxr8io9wJ37iUpY42M --broker-password O5AIZWxelWbLvqMd8PkAVycBJh2Psyg1

Computer says no ¯\_(ツ)_/¯

CONSUMER       | C.VERSION | PROVIDER       | P.VERSION | SUCCESS?
---------------|-----------|----------------|-----------|---------
Banana Service | 1.0.0     | Fofana Service | 1.0.0     | false

The verification between the latest version of Banana Service (1.0.0) and version 1.0.0 of Fofana Service failed

The following are the binaries currently made available:

• pact-mock-service
• pact-broker
• pact-stub-service
• pact-message
• pact-provider-verifier
• pact

Windows Issues

Enable Long Paths

Windows has a default path length limit of 260 causing issues with projects that are nested deep inside several directory and with how npm handles node_modules directory structures. To fix this issue, please enable Windows Long Paths in the registry by running regedit.exe, find the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled and change the value from 0 to 1, then reboot your computer. Pact should now work as it should, if not, please raise an issue on github.

Contributing

To develop this project, simply install the dependencies with npm install --ignore-scripts, and run npm run watch to for continual development, linting and testing when a source file changes.

Testing

Running npm test will execute the tests that has the *.spec.js pattern.

Questions?

Please search for potential answers or post question on our official Pact StackOverflow.