Add contract resolution code, which checks release requirements

Change-type: minor
Signed-off-by: Cameron Diver <cameron@balena.io>

package.json

@@ -37,6 +37,7 @@
     "node": "^6.13.1"
   },
   "devDependencies": {
+    "@balena/contrato": "^0.2.1",
     "@types/bluebird": "^3.5.25",
     "@types/chai": "^4.1.7",
     "@types/common-tags": "^1.8.0",

src/lib/contracts.ts

@@ -0,0 +1,66 @@
+import * as _ from 'lodash';
+
+import { Blueprint, Contract, ContractObject } from '@balena/contrato';
+
+import constants = require('./constants');
+import { InternalInconsistencyError } from './errors';
+import * as osRelease from './os-release';
+import supervisorVersion = require('./supervisor-version');
+
+export async function containerContractsFulfilled(
+	containers: ContractObject[],
+): Promise<boolean> {
+	const osContract = new Contract({
+		slug: 'balenaOS',
+		type: 'sw.os',
+		name: 'balenaOS',
+		version: await osRelease.getOSSemver(constants.hostOSVersionPath),
+	});
+
+	const supervisorContract = new Contract({
+		slug: 'balena-supervisor',
+		type: 'sw.supervisor',
+		name: 'balena-supervisor',
+		version: supervisorVersion,
+	});
+
+	const blueprint = new Blueprint(
+		{
+			'sw.os': 1,
+			'sw.supervisor': 1,
+			'sw.container': '1+',
+		},
+		{
+			type: 'sw.runnable.configuration',
+			slug: '{{children.sw.container.slug}}',
+		},
+	);
+
+	const universe = new Contract({
+		type: 'meta.universe',
+	});
+
+	universe.addChildren(
+		[osContract, supervisorContract].concat(
+			containers.map(c => new Contract(c)),
+		),
+	);
+
+	const solution = blueprint.reproduce(universe);
+
+	if (solution.length > 1) {
+		throw new InternalInconsistencyError(
+			'More than one solution available for container contracts when only one is expected!',
+		);
+	}
+	if (solution.length === 0) {
+		return false;
+	}
+
+	// Detect how many containers are present in the resulting
+	// solution
+	const children = solution[0].getChildren({
+		types: new Set(['sw.container']),
+	});
+	return children.length === containers.length;
+}

test/24-contracts.ts

@@ -0,0 +1,212 @@
+import { assert, expect } from 'chai';
+
+import * as semver from 'balena-semver';
+
+import * as constants from '../src/lib/constants';
+import { containerContractsFulfilled } from '../src/lib/contracts';
+import * as osRelease from '../src/lib/os-release';
+import supervisorVersion = require('../src/lib/supervisor-version');
+
+describe('Container contracts', () => {
+	// Because the supervisor version will change whenever the
+	// package.json will, we generate values which are above
+	// and below the current value, and use these to reason
+	// about the contract engine results
+	const supervisorVersionGreater = `${semver.major(supervisorVersion)! +
+		1}.0.0`;
+	const supervisorVersionLesser = `${semver.major(supervisorVersion)! - 1}.0.0`;
+
+	before(async () => {
+		// We ensure that the versions we're using for testing
+		// are the same as the time of implementation, otherwise
+		// these tests could fail or succeed when they shouldn't
+		expect(await osRelease.getOSSemver(constants.hostOSVersionPath)).to.equal(
+			'2.0.6',
+		);
+		assert(semver.gt(supervisorVersionGreater, supervisorVersion));
+		assert(semver.lt(supervisorVersionLesser, supervisorVersion));
+	});
+
+	it('Should correctly run containers with no requirements', async () => {
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container',
+				},
+			]),
+		).to.equal(true);
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container1',
+				},
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container2',
+				},
+			]),
+		).to.equal(true);
+	});
+
+	it('should correctly run containers whose requirements are satisfied', async () => {
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container',
+					requires: [
+						{
+							type: 'sw.os',
+							version: '>2.0.0',
+						},
+					],
+				},
+			]),
+		).to.equal(true);
+
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `<${supervisorVersionGreater}`,
+						},
+					],
+				},
+			]),
+		).to.equal(true);
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `>${supervisorVersionLesser}`,
+						},
+					],
+				},
+			]),
+		).to.equal(true);
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `>${supervisorVersionLesser}`,
+						},
+						{
+							type: 'sw.os',
+							version: '<3.0.0',
+						},
+					],
+				},
+			]),
+		).to.equal(true);
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container1',
+					slug: 'user-container1',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `>${supervisorVersionLesser}`,
+						},
+					],
+				},
+				{
+					type: 'sw.container',
+					name: 'user-container1',
+					slug: 'user-container1',
+					requires: [
+						{
+							type: 'sw.os',
+							version: '<3.0.0',
+						},
+					],
+				},
+			]),
+		).to.equal(true);
+	});
+
+	it('Should refuse to run containers whose requirements are not satisfied', async () => {
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container',
+					slug: 'user-container',
+					requires: [
+						{
+							type: 'sw.os',
+							version: '>=3.0.0',
+						},
+					],
+				},
+			]),
+		).to.equal(false);
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container2',
+					slug: 'user-container2',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `>=${supervisorVersionLesser}`,
+						},
+						{
+							type: 'sw.os',
+							version: '>3.0.0',
+						},
+					],
+				},
+			]),
+		).to.equal(false);
+		expect(
+			await containerContractsFulfilled([
+				{
+					type: 'sw.container',
+					name: 'user-container1',
+					slug: 'user-container1',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `>=${supervisorVersionLesser}`,
+						},
+					],
+				},
+				{
+					type: 'sw.container',
+					name: 'user-container2',
+					slug: 'user-container2',
+					requires: [
+						{
+							type: 'sw.supervisor',
+							version: `<=${supervisorVersionLesser}`,
+						},
+					],
+				},
+			]),
+		).to.equal(false);
+	});
+});

test/data/etc/os-release

@@ -1,2 +1,3 @@
-PRETTY_NAME="Resin OS 2.0.6 (fake)"
+PRETTY_NAME="balenaOS 2.0.6 (fake)"
 VARIANT_ID="dev"
+VERSION="2.0.6"

test/data/etc/os-release-novariant

@@ -1 +1,2 @@
-PRETTY_NAME="Resin OS 2.0.6 (fake)"
+PRETTY_NAME="balenaOS 2.0.6 (fake)"
+VERSION="2.0.6"