7 files changed, 542 insertions, 0 deletions
diff --git a/shared/logger/src/base.ts b/shared/logger/src/base.ts
new file mode 100644
index 0000000..1f6df0b
--- /dev/null
+++ b/shared/logger/src/base.ts
@@ -0,0 +1,67 @@
+import type { Level, Logger } from './types';
+
+export abstract class BaseLogger<Args extends unknown[] = unknown[]>
+    implements Logger<Args>
+{
+    constructor(protected readonly name: string) {}
+
+    /**
+     * Log a debug level message.
+     * Appropriate for verbose logging that explains steps/details of the inner state of
+     * a code unit.
+     *
+     * Example uses include in a size-constrain datastructure, logging when the size
+     * exceeds the threshold and elements are removed, or in a virtual scrolling
+     * component logging when a scroll event causes a new page of elements to be loaded.
+     *
+     * @param args Arguments to log (same as console.debug)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    debug(...args: Args): string {
+        return this.log('debug', ...args);
+    }
+
+    /**
+     * Log an info level message.
+     * Appropriate for informational messages that may be relevant to consumers of a code
+     * unit.
+     *
+     * Example uses include a router logging when transitions occur or a button logging
+     * clicks.
+     *
+     * @param args Arguments to log (same as console.info)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    info(...args: Args): string {
+        return this.log('info', ...args);
+    }
+
+    /**
+     * Log a warn level message.
+     * Appropriate for situations where state has been (or likely will be) corrupted or
+     * invariants have been broken.
+     *
+     * Example uses include a data structure warning when it is used before being fully
+     * initialized.
+     *
+     * @param args Arguments to log (same as console.warn)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    warn(...args: Args): string {
+        return this.log('warn', ...args);
+    }
+
+    /**
+     * Log an error message.
+     * Appropriate for thrown errors or situations where the apps breaks or has to
+     * engage in fallback behavior to avoid a more catastrophic failure.
+     *
+     * @param args Arguments to log (same as console.error)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    error(...args: Args): string {
+        return this.log('error', ...args);
+    }
+
+    protected abstract log(method: Level, ...args: Args): string;
+}
diff --git a/shared/logger/src/composite.ts b/shared/logger/src/composite.ts
new file mode 100644
index 0000000..a3c4d69
--- /dev/null
+++ b/shared/logger/src/composite.ts
@@ -0,0 +1,92 @@
+import type { LoggerFactory, Logger } from './types';
+
+export class CompositeLoggerFactory implements LoggerFactory {
+    private readonly factories: LoggerFactory[];
+
+    constructor(factories: LoggerFactory[]) {
+        this.factories = factories;
+    }
+
+    loggerFor(name: string): Logger {
+        return new CompositeLogger(
+            this.factories.map((factory) => factory.loggerFor(name)),
+        );
+    }
+}
+
+export class CompositeLogger implements Logger {
+    private readonly loggers: Logger[];
+
+    constructor(loggers: Logger[]) {
+        this.loggers = loggers;
+    }
+
+    /**
+     * Log a debug level message.
+     * Appropriate for verbose logging that explains steps/details of the inner state of
+     * a code unit.
+     *
+     * Example uses include in a size-constrain datastructure, logging when the size
+     * exceeds the threshold and elements are removed, or in a virtual scrolling
+     * component logging when a scroll event causes a new page of elements to be loaded.
+     *
+     * @param args Arguments to log (same as console.debug)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    debug(...args: unknown[]): string {
+        return this.callAll('debug', args);
+    }
+
+    /**
+     * Log an info level message.
+     * Appropriate for informational messages that may be relevant to consumers of a code
+     * unit.
+     *
+     * Example uses include a router logging when transitions occur or a button logging
+     * clicks.
+     *
+     * @param args Arguments to log (same as console.info)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    info(...args: unknown[]): string {
+        return this.callAll('info', args);
+    }
+
+    /**
+     * Log a warn level message.
+     * Appropriate for situations where state has been (or likely will be) corrupted or
+     * invariants have been broken.
+     *
+     * Example uses include a data structure warning when it is used before being fully
+     * initialized.
+     *
+     * @param args Arguments to log (same as console.warn)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    warn(...args: unknown[]): string {
+        return this.callAll('warn', args);
+    }
+
+    /**
+     * Log an error message.
+     * Appropriate for thrown errors or situations where the apps breaks or has to
+     * engage in fallback behavior to avoid a more catastrophic failure.
+     *
+     * @param args Arguments to log (same as console.error)
+     * @return empty string (for use in brackets {} in svelte components)
+     */
+    error(...args: unknown[]): string {
+        return this.callAll('error', args);
+    }
+
+    private callAll(
+        method: 'debug' | 'info' | 'warn' | 'error',
+        args: unknown[],
+    ): string {
+        for (const logger of this.loggers) {
+            logger[method](...args);
+        }
+
+        return '';
+    }
+}
diff --git a/shared/logger/src/console.ts b/shared/logger/src/console.ts
new file mode 100644
index 0000000..408002b
--- /dev/null
+++ b/shared/logger/src/console.ts
@@ -0,0 +1,29 @@
+import { BaseLogger } from './base';
+import type { Level, LoggerFactory, Logger } from './types';
+import { shouldLog } from './local-storage-filter';
+
+export class ConsoleLoggerFactory implements LoggerFactory {
+    loggerFor(name: string): Logger {
+        return new ConsoleLogger(name);
+    }
+}
+
+export class ConsoleLogger extends BaseLogger {
+    protected log(method: Level, ...args: unknown[]): string {
+        if (!shouldLog(this.name, method)) {
+            return '';
+        }
+
+        const log = console[method];
+        const prefix = `[${this.name}]`;
+        const [firstArg, ...rest] = args;
+
+        if (typeof firstArg === 'string') {
+            log(`${prefix} ${firstArg}`, ...rest);
+        } else {
+            log(prefix, ...args);
+        }
+
+        return '';
+    }
+}
diff --git a/shared/logger/src/errorkit/errorkit-logger.ts b/shared/logger/src/errorkit/errorkit-logger.ts
new file mode 100644
index 0000000..1290c41
--- /dev/null
+++ b/shared/logger/src/errorkit/errorkit-logger.ts
@@ -0,0 +1,93 @@
+import type { ErrorHub, ValueOf } from './types';
+import type { LoggerFactory, Logger } from '../types';
+
+/**
+ * Determines the level of logs to send to sentry.
+ *
+ */
+export const ERROR_REPORT_LEVEL = {
+    error: 'error',
+    error_warn: 'error_warn',
+} as const;
+
+type ReportLevel = ValueOf<typeof ERROR_REPORT_LEVEL>;
+
+export class ErrorKitLoggerFactory implements LoggerFactory {
+    private readonly errorKit: ErrorHub;
+    private readonly reportLevel: ReportLevel;
+    constructor(errorKit: ErrorHub, reportLevel?: ReportLevel) {
+        this.errorKit = errorKit;
+        this.reportLevel = reportLevel ?? ERROR_REPORT_LEVEL.error;
+    }
+    loggerFor(name: string): Logger {
+        return new ErrorKitLogger(name, this.errorKit, this.reportLevel);
+    }
+}
+
+interface HasToString {
+    toString(): string;
+}
+
+export class ErrorKitLogger implements Logger {
+    private readonly name: string;
+    private readonly errorKit: ErrorHub;
+    private readonly reportLevel: ReportLevel;
+    constructor(name: string, errorKit: ErrorHub, reportLevel: ReportLevel) {
+        this.name = name;
+        this.errorKit = errorKit;
+        this.reportLevel = reportLevel;
+    }
+
+    private stringifyConsoleArgs(...args: unknown[]): string {
+        return args.reduce((acc: string, val: unknown) => {
+            let tempVal: HasToString;
+            switch (true) {
+                case val instanceof Error: {
+                    tempVal = (val as unknown as InstanceType<typeof Error>)
+                        .message;
+                    break;
+                }
+                case typeof val === 'object': {
+                    try {
+                        tempVal = JSON.stringify(val);
+                    } catch (e) {
+                        tempVal = `failed to stringify ${val}`;
+                    }
+                    break;
+                }
+                case typeof val === 'undefined' || val === null: {
+                    tempVal = `${val}`;
+                    break;
+                }
+                default: {
+                    tempVal = val as HasToString;
+                }
+            }
+
+            return `${acc} ${tempVal.toString()}`;
+        }, `[${this.name}]`) as string;
+    }
+
+    debug(..._args: unknown[]): string {
+        return '';
+    }
+    info(..._args: unknown[]): string {
+        return '';
+    }
+    warn(...args: unknown[]): string {
+        if (this.reportLevel === ERROR_REPORT_LEVEL.error_warn) {
+            this.errorKit.captureMessage(this.stringifyConsoleArgs(...args));
+        }
+        return '';
+    }
+    error(...args: unknown[]): string {
+        const errors = args.filter((item) => item instanceof Error) as Error[];
+        const message = this.stringifyConsoleArgs(...args);
+
+        const error = errors.length === 0 ? new Error(message) : errors[0];
+        error.message = message;
+
+        this.errorKit.captureException(error);
+        return '';
+    }
+}
diff --git a/shared/logger/src/errorkit/errorkit.ts b/shared/logger/src/errorkit/errorkit.ts
new file mode 100644
index 0000000..dd40e26
--- /dev/null
+++ b/shared/logger/src/errorkit/errorkit.ts
@@ -0,0 +1,108 @@
+import { Severity } from '@sentry/types';
+import type { Logger, LoggerFactory } from '../types';
+import type {
+    captureException,
+    captureMessage,
+    addBreadcrumb,
+    ErrorHub,
+    ErrorKitConfig,
+} from './types';
+
+type PartialSentryModule = {
+    captureException: typeof captureException;
+    captureMessage: typeof captureMessage;
+    addBreadcrumb: typeof addBreadcrumb;
+};
+
+export type ErrorKitInstance = InstanceType<typeof ErrorKit>;
+
+export const setupErrorKit = (
+    config: ErrorKitConfig,
+    loggerFactory: LoggerFactory,
+): ErrorKitInstance | undefined => {
+    if (typeof window === 'undefined') return;
+    const log = loggerFactory.loggerFor('errorkit');
+    const isMultiDev = window.location.href.includes('multidev');
+    const BUILD_ENV = process.env.NODE_ENV;
+    const isErrorKitEnabled = BUILD_ENV === 'production' && !isMultiDev;
+
+    const initializeErrorKit =
+        async (): Promise<PartialSentryModule | null> => {
+            let sentry: PartialSentryModule | null = null;
+
+            if (isErrorKitEnabled) {
+                try {
+                    const { createSentryConfig } = await import(
+                        '@amp-metrics/sentrykit'
+                    );
+                    const Sentry = await import('@sentry/browser');
+                    Sentry.init(createSentryConfig(config));
+
+                    sentry = {
+                        addBreadcrumb: Sentry.addBreadcrumb,
+                        captureException: Sentry.captureException,
+                        captureMessage: Sentry.captureMessage,
+                    };
+                } catch (e) {
+                    log.error('something went wrong setting up errorKit', e);
+                }
+            }
+
+            return sentry;
+        };
+
+    return new ErrorKit(initializeErrorKit(), log, isErrorKitEnabled);
+};
+
+class ErrorKit implements ErrorHub {
+    private readonly sentry: Promise<PartialSentryModule | null>;
+    private readonly logger: Logger;
+    private readonly isErrorKitEnabled: boolean;
+    constructor(
+        sentry: Promise<PartialSentryModule | null>,
+        log: Logger,
+        isErrorKitEnabled: boolean,
+    ) {
+        this.sentry = sentry;
+        this.logger = log;
+        this.isErrorKitEnabled = isErrorKitEnabled;
+
+        if (!isErrorKitEnabled) {
+            log.debug('errorkit is disabled');
+        }
+    }
+
+    async captureMessage(message: string) {
+        if (!this.isErrorKitEnabled) return;
+        const sentry = await this.sentry;
+
+        if (sentry) {
+            sentry.addBreadcrumb({
+                category: 'log.warn',
+                level: Severity.Warning,
+            });
+            sentry.captureMessage(message, Severity.Warning);
+        } else {
+            this.logger.warn(`${message} was not sent to errorKit`);
+        }
+    }
+
+    async captureException(exception: Error) {
+        if (!this.isErrorKitEnabled) return;
+        const sentry = await this.sentry;
+
+        if (sentry) {
+            sentry.addBreadcrumb({
+                type: 'error',
+                category: 'error',
+                level: Severity.Error,
+            });
+            sentry.captureException(exception);
+        } else {
+            this.logger.warn(
+                `The following exception was not sent to errorKit:`,
+                exception,
+            );
+        }
+    }
+}
diff --git a/shared/logger/src/index.ts b/shared/logger/src/index.ts
new file mode 100644
index 0000000..dc786e3
--- /dev/null
+++ b/shared/logger/src/index.ts
@@ -0,0 +1,31 @@
+import { getContext } from 'svelte';
+import type { Logger, LoggerFactory } from './types';
+
+export * from './composite';
+export * from './console';
+export * from './deferred';
+export * from './recording';
+export * from './sampled';
+export * from './types';
+export * from './void';
+
+const CONTEXT_NAME = 'loggerFactory';
+
+export function setContext(
+    context: Map<string, unknown>,
+    factory: LoggerFactory,
+): void {
+    context.set(CONTEXT_NAME, factory);
+}
+
+export function loggerFor(subject: string): Logger {
+    const factory = getContext(CONTEXT_NAME) as LoggerFactory | undefined;
+
+    if (!factory) {
+        throw new Error(
+            'loggerFor called before setContext or outside of svelte component init',
+        );
+    }
+
+    return factory.loggerFor(subject);
+}
diff --git a/shared/logger/src/local-storage-filter.ts b/shared/logger/src/local-storage-filter.ts
new file mode 100644
index 0000000..18a42fa
--- /dev/null
+++ b/shared/logger/src/local-storage-filter.ts
@@ -0,0 +1,122 @@
+export type Level = 'debug' | 'info' | 'warn' | 'error';
+// Numbers correspond to the levels above, with 0 meaning "no level"
+type LevelNum = 4 | 3 | 2 | 1 | 0;
+
+interface Rules {
+    named?: Record<string, LevelNum>;
+    defaultLevel?: LevelNum;
+}
+
+const LEVEL_TO_NUM: Record<Level | 'off' | '*' | '', LevelNum> = {
+    '*': 4,
+    debug: 4,
+    info: 3,
+    warn: 2,
+    error: 1,
+    off: 0,
+    '': 0,
+};
+
+/**
+ * Parses log filtering instructions from localStorage.onyxLog.
+ * The instructions are a series of comma separated directives that restrict
+ * logging. Restrictions indicate the highest log level that a named logger
+ * will emit. The name of the logger is the string passed to
+ * LoggerFactory.loggerFor.
+ *
+ * By default (ex. empty rule string), no logs will be emitted.
+ *
+ * The format of the directives is NAME=LEVEL. LEVEL can be one of:
+ *
+ *   - * - all levels are logged (debug, info, warn, error)
+ *   - debug - same as above
+ *   - info - everything but debug is logged
+ *   - warn - everything but info and debug is logged
+ *   - error - only errors are logged
+ *   - off (or empty string, ex. "MyClass=") - nothing will be logged
+ *
+ * Some examples:
+ *
+ *   - '*=*' will emit all log levels from all loggers
+ *   - '*=info,Foo=off' will emit everything but debug except or logs from
+ *     the named logger Foo (which will be entirely suppressed)
+ *   - 'Bar=error,Baz=warn' will emit errors from Bar and Baz and warnings from
+ *     Baz
+ *
+ * NOTE: Keep this in sync with README.md!
+ */
+function parseRules(): Rules {
+    const onyxLog: string = (() => {
+        try {
+            // The typeof check is for SSR
+            return (
+                (typeof window !== 'undefined'
+                    ? window.localStorage.onyxLog
+                    : '') || ''
+            );
+        } catch {
+            // window.localStorage will throw when referenced (at all) when
+            // Chrome has it disabled
+            // See: rdar://93367396 (Guard localStorage and sessionStorage use)
+            return '';
+        }
+    })();
+
+    const PRODUCTION_DEFAULT = {}; // no logs unless specified
+    const DEV_DEFAULT = {
+        defaultLevel: LEVEL_TO_NUM['*'], // All logs unless specified
+    };
+    const isDevelopment = (() => {
+        // This is a little tricky. The ENV var is not real. It's replaced by
+        // rollup-plugin-replace. Thus, we can't do the usual of testing for
+        // the existence of `process` and then doing `process?.env` etc.
+        // Instead, we just try the whole thing and try/catch. This way,
+        // rollup-plugin-replace sees that entire string verbatim and can
+        // replace it with the proper environment.
+        try {
+            // @ts-ignore
+            return process.env.NODE_ENV !== 'production';
+        } catch {
+            return false;
+        }
+    })();
+    const defaultRules = isDevelopment ? DEV_DEFAULT : PRODUCTION_DEFAULT;
+
+    // If the localStorage is specified, start from a clean slate. Otherwise,
+    // use the environment default
+    const rules: Rules = onyxLog.length > 0 ? {} : defaultRules;
+
+    for (const directive of onyxLog.split(',').filter((v) => v)) {
+        // Invalid directive, must be of the form 'name=level'
+        const parts = directive.split('=');
+        if (parts.length !== 2) {
+            continue;
+        }
+
+        const [name, maxLevelName] = parts;
+        const maxLevel =
+            LEVEL_TO_NUM[maxLevelName as keyof typeof LEVEL_TO_NUM];
+
+        // Invalid level
+        if (typeof maxLevel === 'undefined') {
+            continue;
+        }
+
+        if (name === '*') {
+            rules.defaultLevel = maxLevel;
+        } else {
+            rules.named = rules.named ?? {};
+            rules.named[name] = maxLevel;
+        }
+    }
+
+    return rules;
+}
+
+export function shouldLog(name: string, level: Level): boolean {
+    const rules = parseRules();
+
+    // Rules for the named logger take precedence over the default
+    const maxLevel = (rules.named || {})[name] ?? rules.defaultLevel ?? 0;
+    return LEVEL_TO_NUM[level] <= maxLevel;
+}