backstage

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/*
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 * Copyright 2023 The Backstage Authors
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *     http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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import { Config } from '@backstage/config';
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import { InputError } from '@backstage/errors';
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import { HumanDuration } from '@backstage/types';
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export const propsOfHumanDuration = [
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  'years',
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  'months',
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  'weeks',
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  'days',
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  'hours',
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  'minutes',
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  'seconds',
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  'milliseconds',
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];
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/**
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 * Reads a duration from a config object.
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 *
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 * @public
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 * @remarks
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 *
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 * This does not support optionality; if you want to support optional durations,
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 * you need to first check the presence of the target with `config.has(...)` and
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 * then call this function.
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 *
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 * @param config - A configuration object
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 * @param key - If specified, read the duration from the given subkey
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 *        under the config object
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 * @returns A duration object
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 */
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export function readDurationFromConfig(
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  config: Config,
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  options?: {
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    key?: string;
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  },
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): HumanDuration {
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  let root: Config;
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  let found = false;
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  const result: Record<string, number> = {};
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  try {
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    root = options?.key ? config.getConfig(options.key) : config;
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    for (const prop of propsOfHumanDuration) {
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      const value = root.getOptionalNumber(prop);
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      if (value !== undefined) {
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        result[prop] = value;
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        found = true;
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      }
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    }
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  } catch (error) {
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    // This needs no contextual key prefix since the config reader adds it to
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    // its own errors
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    throw new InputError(`Failed to read duration from config, ${error}`);
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  }
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  try {
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    if (!found) {
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      const good = propsOfHumanDuration.map(p => `'${p}'`).join(', ');
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      throw new Error(`Needs one or more of ${good}`);
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    }
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    const invalidProps = root
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      .keys()
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      .filter(prop => !propsOfHumanDuration.includes(prop));
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    if (invalidProps.length) {
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      const what = invalidProps.length === 1 ? 'property' : 'properties';
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      const bad = invalidProps.map(p => `'${p}'`).join(', ');
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      const good = propsOfHumanDuration.map(p => `'${p}'`).join(', ');
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      throw new Error(
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        `Unknown ${what} ${bad}; expected one or more of ${good}`,
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      );
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    }
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  } catch (error) {
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    // For our own errors, even though we don't know where we are anchored in
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    // the config hierarchy, we try to be helpful and at least add the subkey if
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    // we have it
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    let prefix = 'Failed to read duration from config';
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    if (options?.key) {
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      prefix += ` at '${options.key}'`;
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    }
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    throw new InputError(`${prefix}, ${error}`);
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  }
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  return result as HumanDuration;
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}
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