Files
pictshare/storage-controllers/s3/Aws/EndpointDiscovery/ConfigurationProvider.php
2020-01-05 03:11:41 +01:00

334 lines
11 KiB
PHP

<?php
namespace Aws\EndpointDiscovery;
use Aws\CacheInterface;
use Aws\EndpointDiscovery\Exception\ConfigurationException;
use GuzzleHttp\Promise;
use GuzzleHttp\Promise\PromiseInterface;
/**
* A configuration provider is a function that returns a promise that is
* fulfilled with a {@see \Aws\EndpointDiscovery\ConfigurationInterface}
* or rejected with an {@see \Aws\EndpointDiscovery\Exception\ConfigurationException}.
*
* <code>
* use Aws\EndpointDiscovery\ConfigurationProvider;
* $provider = ConfigurationProvider::defaultProvider();
* // Returns a ConfigurationInterface or throws.
* $config = $provider()->wait();
* </code>
*
* Configuration providers can be composed to create configuration using
* conditional logic that can create different configurations in different
* environments. You can compose multiple providers into a single provider using
* {@see Aws\EndpointDiscovery\ConfigurationProvider::chain}. This function
* accepts providers as variadic arguments and returns a new function that will
* invoke each provider until a successful configuration is returned.
*
* <code>
* // First try an INI file at this location.
* $a = ConfigurationProvider::ini(null, '/path/to/file.ini');
* // Then try an INI file at this location.
* $b = ConfigurationProvider::ini(null, '/path/to/other-file.ini');
* // Then try loading from environment variables.
* $c = ConfigurationProvider::env();
* // Combine the three providers together.
* $composed = ConfigurationProvider::chain($a, $b, $c);
* // Returns a promise that is fulfilled with a configuration or throws.
* $promise = $composed();
* // Wait on the configuration to resolve.
* $config = $promise->wait();
* </code>
*/
class ConfigurationProvider
{
const CACHE_KEY = 'aws_cached_endpoint_discovery_config';
const DEFAULT_ENABLED = false;
const DEFAULT_CACHE_LIMIT = 1000;
const ENV_ENABLED = 'AWS_ENDPOINT_DISCOVERY_ENABLED';
const ENV_ENABLED_ALT = 'AWS_ENABLE_ENDPOINT_DISCOVERY';
const ENV_PROFILE = 'AWS_PROFILE';
/**
* Wraps a config provider and saves provided configuration in an
* instance of Aws\CacheInterface. Forwards calls when no config found
* in cache and updates cache with the results.
*
* @param callable $provider Configuration provider function to wrap
* @param CacheInterface $cache Cache to store credentials
* @param string|null $cacheKey (optional) Cache key to use
*
* @return callable
*/
public static function cache(
callable $provider,
CacheInterface $cache,
$cacheKey = null
) {
$cacheKey = $cacheKey ?: self::CACHE_KEY;
return function () use ($provider, $cache, $cacheKey) {
$found = $cache->get($cacheKey);
if ($found instanceof ConfigurationInterface) {
return Promise\promise_for($found);
}
return $provider()
->then(function (ConfigurationInterface $config) use (
$cache,
$cacheKey
) {
$cache->set($cacheKey, $config);
return $config;
});
};
}
/**
* Creates an aggregate credentials provider that invokes the provided
* variadic providers one after the other until a provider returns
* credentials.
*
* @return callable
*/
public static function chain()
{
$links = func_get_args();
if (empty($links)) {
throw new \InvalidArgumentException('No providers in chain');
}
return function () use ($links) {
/** @var callable $parent */
$parent = array_shift($links);
$promise = $parent();
while ($next = array_shift($links)) {
$promise = $promise->otherwise($next);
}
return $promise;
};
}
/**
* Create a default config provider that first checks for environment
* variables, then checks for a specified profile in ~/.aws/config, then
* checks for the "default" profile in ~/.aws/config, and failing those uses
* a default fallback set of configuration options.
*
* This provider is automatically wrapped in a memoize function that caches
* previously provided config options.
*
* @param array $config Optional array of ecs/instance profile credentials
* provider options.
*
* @return callable
*/
public static function defaultProvider(array $config = [])
{
$configProviders = [
self::env(),
self::ini(),
self::fallback()
];
$memo = self::memoize(
call_user_func_array('self::chain', $configProviders)
);
if (isset($config['endpoint_discovery'])
&& $config['endpoint_discovery'] instanceof CacheInterface
) {
return self::cache($memo, $config['endpoint_discovery'], self::CACHE_KEY);
}
return $memo;
}
/**
* Provider that creates config from environment variables.
*
* @param $cacheLimit
* @return callable
*/
public static function env($cacheLimit = self::DEFAULT_CACHE_LIMIT)
{
return function () use ($cacheLimit) {
// Use config from environment variables, if available
$enabled = getenv(self::ENV_ENABLED);
if ($enabled === false || $enabled === '') {
$enabled = getenv(self::ENV_ENABLED_ALT);
}
if ($enabled !== false && $enabled !== '') {
return Promise\promise_for(
new Configuration($enabled, $cacheLimit)
);
}
return self::reject('Could not find environment variable config'
. ' in ' . self::ENV_ENABLED);
};
}
/**
* Fallback config options when other sources are not set.
*
* @return callable
*/
public static function fallback()
{
return function () {
return Promise\promise_for(
new Configuration(
self::DEFAULT_ENABLED,
self::DEFAULT_CACHE_LIMIT
)
);
};
}
/**
* Gets the environment's HOME directory if available.
*
* @return null|string
*/
private static function getHomeDir()
{
// On Linux/Unix-like systems, use the HOME environment variable
if ($homeDir = getenv('HOME')) {
return $homeDir;
}
// Get the HOMEDRIVE and HOMEPATH values for Windows hosts
$homeDrive = getenv('HOMEDRIVE');
$homePath = getenv('HOMEPATH');
return ($homeDrive && $homePath) ? $homeDrive . $homePath : null;
}
/**
* Config provider that creates config using an ini file stored
* in the current user's home directory.
*
* @param string|null $profile Profile to use. If not specified will use
* the "default" profile in "~/.aws/config".
* @param string|null $filename If provided, uses a custom filename rather
* than looking in the home directory.
* @param int $cacheLimit
*
* @return callable
*/
public static function ini(
$profile = null,
$filename = null,
$cacheLimit = self::DEFAULT_CACHE_LIMIT
) {
$filename = $filename ?: (self::getHomeDir() . '/.aws/config');
$profile = $profile ?: (getenv(self::ENV_PROFILE) ?: 'default');
return function () use ($profile, $filename, $cacheLimit) {
if (!is_readable($filename)) {
return self::reject("Cannot read configuration from $filename");
}
$data = \Aws\parse_ini_file($filename, true);
if ($data === false) {
return self::reject("Invalid config file: $filename");
}
if (!isset($data[$profile])) {
return self::reject("'$profile' not found in config file");
}
if (!isset($data[$profile]['endpoint_discovery_enabled'])) {
return self::reject("Required endpoint discovery config values
not present in INI profile '{$profile}' ({$filename})");
}
return Promise\promise_for(
new Configuration(
$data[$profile]['endpoint_discovery_enabled'],
$cacheLimit
)
);
};
}
/**
* Wraps a config provider and caches previously provided configuration.
*
* Ensures that cached configuration is refreshed when it expires.
*
* @param callable $provider Config provider function to wrap.
*
* @return callable
*/
public static function memoize(callable $provider)
{
return function () use ($provider) {
static $result;
static $isConstant;
// Constant config will be returned constantly.
if ($isConstant) {
return $result;
}
// Create the initial promise that will be used as the cached value
// until it expires.
if (null === $result) {
$result = $provider();
}
// Return config and set flag that provider is already set
return $result
->then(function (ConfigurationInterface $config) use (&$isConstant) {
$isConstant = true;
return $config;
});
};
}
/**
* Reject promise with standardized exception.
*
* @param $msg
* @return Promise\RejectedPromise
*/
private static function reject($msg)
{
return new Promise\RejectedPromise(new ConfigurationException($msg));
}
/**
* Unwraps a configuration object in whatever valid form it is in,
* always returning a ConfigurationInterface object.
*
* @param mixed $config
* @return ConfigurationInterface
* @throws \InvalidArgumentException
*/
public static function unwrap($config)
{
if (is_callable($config)) {
$config = $config();
}
if ($config instanceof PromiseInterface) {
$config = $config->wait();
}
if ($config instanceof ConfigurationInterface) {
return $config;
} elseif (is_array($config) && isset($config['enabled'])) {
if (isset($config['cache_limit'])) {
return new Configuration(
$config['enabled'],
$config['cache_limit']
);
}
return new Configuration(
$config['enabled'],
self::DEFAULT_CACHE_LIMIT
);
}
throw new \InvalidArgumentException('Not a valid endpoint_discovery '
. 'configuration argument.');
}
}