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feat(context-providers) Refactor to enable context providers properties
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* Add Hosted Zone Provider
* Enabling complex filter types for context provider keys
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@moofish32
moofish32 committed Oct 7, 2018
1 parent 6c523f2 commit f6c1ec2
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Showing 11 changed files with 286 additions and 127 deletions.
13 changes: 8 additions & 5 deletions packages/@aws-cdk/aws-ec2/lib/machine-image.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -25,10 +25,11 @@ export class WindowsImage implements IMachineImageSource {
* Return the image to use in the given context
*/
public getImage(parent: Construct): MachineImage {
const ssmProvider = new SSMParameterProvider(parent);
const ssmProvider = new SSMParameterProvider(parent, {
parameterName: this.imageParameterName(this.version),
});

const parameterName = this.imageParameterName(this.version);
const ami = ssmProvider.getString(parameterName);
const ami = ssmProvider.parameterValue();
return new MachineImage(ami, new WindowsOS());
}

Expand Down Expand Up @@ -98,8 +99,10 @@ export class AmazonLinuxImage implements IMachineImageSource {

const parameterName = '/aws/service/ami-amazon-linux-latest/' + parts.join('-');

const ssmProvider = new SSMParameterProvider(parent);
const ami = ssmProvider.getString(parameterName);
const ssmProvider = new SSMParameterProvider(parent, {
parameterName,
});
const ami = ssmProvider.parameterValue();
return new MachineImage(ami, new LinuxOS());
}
}
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4 changes: 2 additions & 2 deletions packages/@aws-cdk/cdk/lib/cloudformation/stack.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -65,7 +65,7 @@ export class Stack extends Construct {
* This is returned when the stack is synthesized under the 'missing' attribute
* and allows tooling to obtain the context and re-synthesize.
*/
public readonly missingContext: { [key: string]: cxapi.MissingContext } = { };
public readonly missingContext: { [key: string]: cxapi.ContextProviderProps } = { };

/**
* The environment in which this stack is deployed.
Expand Down Expand Up @@ -181,7 +181,7 @@ export class Stack extends Construct {
* @param key Key that uniquely identifies this missing context.
* @param details The set of parameters needed to obtain the context (specific to context provider).
*/
public reportMissingContext(key: string, details: cxapi.MissingContext) {
public reportMissingContext(key: string, details: cxapi.ContextProviderProps) {
this.missingContext[key] = details;
}

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174 changes: 111 additions & 63 deletions packages/@aws-cdk/cdk/lib/context.ts
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Original file line number Diff line number Diff line change
@@ -1,8 +1,10 @@
import cxapi = require('@aws-cdk/cx-api');
import { Stack } from './cloudformation/stack';
import { Construct } from './core/construct';

const AVAILABILITY_ZONES_PROVIDER = 'availability-zones';
const SSM_PARAMETER_PROVIDER = 'ssm';
const HOSTED_ZONE_PROVIDER = 'hosted-zone';

/**
* Base class for the model side of context providers
Expand All @@ -16,39 +18,56 @@ const SSM_PARAMETER_PROVIDER = 'ssm';
export class ContextProvider {

private readonly stack: Stack;
private readonly provider: string;
private readonly props: {[key: string]: any};

constructor(private context: Construct) {
constructor(private context: Construct, provider: string, props: {[key: string]: any} = {}) {
this.stack = Stack.find(context);
this.provider = provider;
this.props = props;
}

public get key(): string {
const account = this.account;
const region = this.region;
let keyStr = `${this.provider}:${account}:${region}`;
const propStrings: string[] = this.objectToString(this.props);
if (propStrings.length > 0) {
keyStr += ':';
keyStr += propStrings.join(':');
}
return keyStr;
}
/**
* Read a provider value, verifying it's a string
* @param provider The name of the context provider
* @param scope The scope (e.g. account/region) for the value
* @param args Any arguments
* @param defaultValue The value to return if there is no value defined for this context key
*/
public getStringValue(
provider: string,
scope: undefined | string[],
args: string[],
defaultValue: string): string {
public getStringValue( defaultValue: string): string {
// if scope is undefined, this is probably a test mode, so we just
// return the default value
if (!scope) {
this.context.addError(formatMissingScopeError(provider, args));
if (!this.account || !this.region) {
this.context.addError(formatMissingScopeError(this.provider, this.props));
return defaultValue;
}
const key = colonQuote([provider].concat(scope).concat(args)).join(':');
const value = this.context.getContext(key);

const value = this.context.getContext(this.key);

if (value != null) {
if (typeof value !== 'string') {
throw new TypeError(`Expected context parameter '${key}' to be a string, but got '${value}'`);
throw new TypeError(`Expected context parameter '${this.key}' to be a string, but got '${value}'`);
}
return value;
}

this.stack.reportMissingContext(key, { provider, scope, args });
this.stack.reportMissingContext(this.key, {
provider: this.provider,
account: this.account,
region: this.region,
props: this.props,
});
return defaultValue;
}

Expand All @@ -60,50 +79,65 @@ export class ContextProvider {
* @param defaultValue The value to return if there is no value defined for this context key
*/
public getStringListValue(
provider: string,
scope: undefined | string[],
args: string[],
defaultValue: string[]): string[] {
// if scope is undefined, this is probably a test mode, so we just
// return the default value and report an error so this in not accidentally used
// in the toolkit
if (!scope) {
// tslint:disable-next-line:max-line-length
this.context.addError(formatMissingScopeError(provider, args));
return defaultValue;
}
// if scope is undefined, this is probably a test mode, so we just
// return the default value and report an error so this in not accidentally used
// in the toolkit
if (!this.account || !this.region) {
this.context.addError(formatMissingScopeError(this.provider, this.props));
return defaultValue;
}

const key = colonQuote([provider].concat(scope).concat(args)).join(':');
const value = this.context.getContext(key);
const value = this.context.getContext(this.key);

if (value != null) {
if (!value.map) {
throw new Error(`Context value '${key}' is supposed to be a list, got '${value}'`);
if (value != null) {
if (!value.map) {
throw new Error(`Context value '${this.key}' is supposed to be a list, got '${value}'`);
}
return value;
}
return value;
}

this.stack.reportMissingContext(key, { provider, scope, args });
return defaultValue;
}
this.stack.reportMissingContext(this.key, {
provider: this.provider,
account: this.account,
region: this.region,
props: this.props,
});

/**
* Helper function to wrap up account and region into a scope tuple
*/
public accountRegionScope(providerDescription: string): undefined | string[] {
const stack = Stack.find(this.context);
if (!stack) {
throw new Error(`${providerDescription}: construct must be in a stack`);
return defaultValue;
}

const account = stack.env.account;
const region = stack.env.region;

if (account == null || region == null) {
return undefined;
private objectToString(obj: any): string[] {
const objStr: string[] = [];
const keys = Object.keys(obj);
keys.sort();
for (const key of keys) {
switch (typeof obj[key]) {
case 'object': {
const childObjStrs = this.objectToString(obj[key]);
const qualifiedChildStr = childObjStrs.map( child => (`${key}${child}`)).join(':');
objStr.push(qualifiedChildStr);
break;
}
case 'string': {
objStr.push(`${key}=${colonQuote(obj[key])}`);
break;
}
default: {
objStr.push(`${key}=${JSON.stringify(obj[key])}`);
break;
}
}
}
return objStr;
}

return [account, region];
private get account(): string | undefined {
return this.stack.env.account;
}

private get region(): string | undefined {
return this.stack.env.region;
}
}

Expand All @@ -113,8 +147,8 @@ export class ContextProvider {
* We'll use $ as a quoting character, for no particularly good reason other
* than that \ is going to lead to quoting hell when the keys are stored in JSON.
*/
function colonQuote(xs: string[]): string[] {
return xs.map(x => x.replace('$', '$$').replace(':', '$:'));
function colonQuote(xs: string): string {
return xs.replace('$', '$$').replace(':', '$:');
}

/**
Expand All @@ -124,45 +158,59 @@ export class AvailabilityZoneProvider {
private provider: ContextProvider;

constructor(context: Construct) {
this.provider = new ContextProvider(context);
this.provider = new ContextProvider(context, AVAILABILITY_ZONES_PROVIDER);
}

/**
* Return the list of AZs for the current account and region
*/
public get availabilityZones(): string[] {
return this.provider.getStringListValue(AVAILABILITY_ZONES_PROVIDER,
this.provider.accountRegionScope('AvailabilityZoneProvider'),
[],
['dummy1a', 'dummy1b', 'dummy1c']);

return this.provider.getStringListValue(['dummy1a', 'dummy1b', 'dummy1c']);
}
}

export interface SSMParameterProviderProps {
parameterName: string;
}
/**
* Context provider that will read values from the SSM parameter store in the indicated account and region
*/
export class SSMParameterProvider {
private provider: ContextProvider;

constructor(context: Construct) {
this.provider = new ContextProvider(context);
constructor(context: Construct, props: SSMParameterProviderProps) {
this.provider = new ContextProvider(context, SSM_PARAMETER_PROVIDER, props);
}

/**
* Return the SSM parameter string with the indicated key
*/
public getString(parameterName: string): any {
const scope = this.provider.accountRegionScope('SSMParameterProvider');
return this.provider.getStringValue(SSM_PARAMETER_PROVIDER, scope, [parameterName], 'dummy');
public parameterValue(): any {
return this.provider.getStringValue('dummy');
}
}

function formatMissingScopeError(provider: string, args: string[]) {
let s = `Cannot determine scope for context provider ${provider}`;
if (args.length > 0) {
s += JSON.stringify(args);
/**
* Context provider that will lookup the Hosted Zone ID for the given arguments
*/
export class HostedZoneProvider {
private provider: ContextProvider;
constructor(context: Construct, props: cxapi.HostedZoneProviderProps) {
this.provider = new ContextProvider(context, HOSTED_ZONE_PROVIDER, props);
}
/**
* Return the hosted zone meeting the filter
*/
public zoneId(): string {
return this.provider.getStringValue('dummy-zone');
}
s += '.';
}

function formatMissingScopeError(provider: string, props: {[key: string]: string}) {
let s = `Cannot determine scope for context provider ${provider}`;
const propsString = Object.keys(props).map( key => (`${key}=${props[key]}`));
s += ` with props: ${propsString}.`;
s += '\n';
s += 'This usually happens when AWS credentials are not available and the default account/region cannot be determined.';
return s;
Expand Down
48 changes: 21 additions & 27 deletions packages/@aws-cdk/cdk/test/test.app.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -254,16 +254,20 @@ export = {
super(parent, name, props);

this.reportMissingContext('missing-context-key', {
provider: 'ctx-provider',
args: [ 'arg1', 'arg2' ],
scope: [ 'scope1', 'scope2' ]
});
provider: 'fake',
account: '12345689012',
region: 'ab-north-1',
props: {},
},
);

this.reportMissingContext('missing-context-key-2', {
provider: 'ctx-provider',
args: [ 'arg1', 'arg2' ],
scope: [ 'scope1', 'scope2' ]
});
provider: 'fake2',
account: '12345689012',
region: 'ab-south-1',
props: {foo: 'bar'},
},
);
}
}

Expand All @@ -275,27 +279,17 @@ export = {

test.deepEqual(response.stacks[0].missing, {
"missing-context-key": {
provider: "ctx-provider",
args: [
"arg1",
"arg2"
],
scope: [
"scope1",
"scope2"
]
provider: 'fake',
account: '12345689012',
region: 'ab-north-1',
props: {},
},
"missing-context-key-2": {
provider: "ctx-provider",
args: [
"arg1",
"arg2"
],
scope: [
"scope1",
"scope2"
]
}
provider: 'fake2',
account: '12345689012',
region: 'ab-south-1',
props: {foo: 'bar'},
},
});

test.done();
Expand Down
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