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keelerm84keelerm84
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feat: Implement migrator read and write methods (#133)
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5 files changed

+477
-10
lines changed

5 files changed

+477
-10
lines changed

‎src/LaunchDarkly/Impl/Migrations/Executor.php‎

Lines changed: 56 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,56 @@
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<?php
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declare(strict_types=1);
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namespace LaunchDarkly\Impl\Migrations;
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use Closure;
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use Exception;
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use LaunchDarkly\Impl\Util;
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use LaunchDarkly\Migrations\OperationResult;
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use LaunchDarkly\Migrations\OpTracker;
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use LaunchDarkly\Migrations\Origin;
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use LaunchDarkly\Types\Result;
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/**
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* Utility class for executing migration operations while also tracking our
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* built-in migration measurements.
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*/
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class Executor
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{
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/**
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* @param Closure(mixed): Result $fn
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*/
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public function __construct(
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public readonly Origin $origin,
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private Closure $fn,
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private OpTracker $tracker,
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private bool $trackLatency,
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private bool $trackErrors,
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private mixed $payload,
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) {
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}
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public function run(): OperationResult
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{
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$start = Util::currentTimeUnixMillis();
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try {
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$result = ($this->fn)($this->payload);
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} catch (Exception $e) {
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$result = Result::error($e->getMessage(), $e);
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}
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if ($this->trackLatency) {
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$this->tracker->latency($this->origin, Util::currentTimeUnixMillis() - $start);
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}
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if ($this->trackErrors && !$result->isSuccessful()) {
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$this->tracker->error($this->origin);
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}
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$this->tracker->invoked($this->origin);
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return new OperationResult($this->origin, $result);
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}
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}

‎src/LaunchDarkly/Migrations/Migrator.php‎

Lines changed: 84 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -4,10 +4,10 @@
44

55
namespace LaunchDarkly\Migrations;
66

7+
use LaunchDarkly\Impl\Migrations\Executor;
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use LaunchDarkly\LDClient;
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use LaunchDarkly\LDContext;
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use LaunchDarkly\LDUser;
10-
use LaunchDarkly\Types\Result;
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/**
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* Migrator is a class for performing a technology migration.
@@ -22,8 +22,8 @@ public function __construct(
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private ExecutionOrder $executionOrder,
2323
private MigrationConfig $readConfig,
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private MigrationConfig $writeConfig,
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private bool $measureLatency,
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private bool $measureErrors,
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private bool $trackLatency,
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private bool $trackErrors,
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) {
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}
2929

@@ -36,9 +36,28 @@ public function read(
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Stage $defaultStage,
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mixed $payload = null
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): OperationResult {
39-
// TODO(sc-219376): Implement later
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$variationResult = $this->client->migrationVariation($key, $context, $defaultStage);
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/** @var Stage */
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$stage = $variationResult['stage'];
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/** @var OpTracker */
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$tracker = $variationResult['tracker'];
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$tracker->operation(Operation::READ);
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41-
return new OperationResult(Origin::OLD, Result::success(null));
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$old = new Executor(Origin::OLD, $this->readConfig->old, $tracker, $this->trackLatency, $this->trackErrors, $payload);
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$new = new Executor(Origin::NEW, $this->readConfig->new, $tracker, $this->trackLatency, $this->trackErrors, $payload);
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$result = match ($stage) {
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Stage::OFF => $old->run(),
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Stage::DUALWRITE => $old->run(),
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Stage::SHADOW => $this->readBoth($old, $new, $tracker),
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Stage::LIVE => $this->readBoth($new, $old, $tracker),
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Stage::RAMPDOWN => $new->run(),
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Stage::COMPLETE => $new->run(),
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};
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// TODO(sc-219377): Emit the event here
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return $result;
4261
}
4362

4463
/**
@@ -49,9 +68,65 @@ public function write(
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LDContext|LDUser $context,
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Stage $defaultStage,
5170
mixed $payload = null
52-
): OperationResult {
53-
// TODO(sc-219376): Implement later
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//
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return new OperationResult(Origin::OLD, Result::success(null));
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): WriteResult {
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$variationResult = $this->client->migrationVariation($key, $context, $defaultStage);
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/** @var Stage */
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$stage = $variationResult['stage'];
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/** @var OpTracker */
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$tracker = $variationResult['tracker'];
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$tracker->operation(Operation::READ);
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$old = new Executor(Origin::OLD, $this->writeConfig->old, $tracker, $this->trackLatency, $this->trackErrors, $payload);
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$new = new Executor(Origin::NEW, $this->writeConfig->new, $tracker, $this->trackLatency, $this->trackErrors, $payload);
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$writeResult = match ($stage) {
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Stage::OFF => new WriteResult($old->run()),
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Stage::DUALWRITE => $this->writeBoth($old, $new, $tracker),
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Stage::SHADOW => $this->writeBoth($old, $new, $tracker),
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Stage::LIVE => $this->writeBoth($new, $old, $tracker),
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Stage::RAMPDOWN => $this->writeBoth($new, $old, $tracker),
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Stage::COMPLETE => new WriteResult($new->run()),
89+
};
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// TODO(sc-219377): Emit the event here
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return $writeResult;
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}
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private function readBoth(Executor $authoritative, Executor $nonauthoritative, OpTracker $tracker): OperationResult
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{
98+
// TODO(sc-219378): Add sampling to limit to 50% chance
99+
if ($this->executionOrder == ExecutionOrder::RANDOM) {
100+
$nonauthoritativeResult = $nonauthoritative->run();
101+
$authoritativeResult = $authoritative->run();
102+
} else {
103+
$authoritativeResult = $authoritative->run();
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$nonauthoritativeResult = $nonauthoritative->run();
105+
}
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107+
if ($this->readConfig->comparison === null) {
108+
return $authoritativeResult;
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}
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if ($authoritativeResult->isSuccessful() && $nonauthoritativeResult->isSuccessful()) {
112+
$tracker->consistent(fn (): bool => ($this->readConfig->comparison)($authoritativeResult->value, $nonauthoritativeResult->value));
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}
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return $authoritativeResult;
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}
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private function writeBoth(Executor $authoritative, Executor $nonauthoritative, OpTracker $tracker): WriteResult
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{
120+
$authoritativeResult = $authoritative->run();
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$tracker->invoked($authoritative->origin);
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123+
if (!$authoritativeResult->isSuccessful()) {
124+
return new WriteResult($authoritativeResult);
125+
}
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127+
$nonauthoritativeResult = $nonauthoritative->run();
128+
$tracker->invoked($nonauthoritative->origin);
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return new WriteResult($authoritativeResult, $nonauthoritativeResult);
56131
}
57132
}

‎src/LaunchDarkly/Migrations/OperationResult.php‎

Lines changed: 17 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,16 +4,32 @@
44

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namespace LaunchDarkly\Migrations;
66

7+
use Exception;
78
use LaunchDarkly\Types\Result;
89

910
/**
1011
* The OperationResult pairs an origin with a result.
1112
*/
1213
class OperationResult
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{
15+
public readonly mixed $value;
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public readonly ?string $error;
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public readonly ?Exception $exception;
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1419
public function __construct(
1520
public readonly Origin $origin,
16-
public readonly Result $result
21+
private readonly Result $result
1722
) {
23+
$this->value = $result->value;
24+
$this->error = $result->error;
25+
$this->exception = $result->exception;
26+
}
27+
28+
/**
29+
* Determine whether this result represents success or failure.
30+
*/
31+
public function isSuccessful(): bool
32+
{
33+
return $this->result->isSuccessful();
1834
}
1935
}

‎src/LaunchDarkly/Migrations/WriteResult.php‎

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
1+
<?php
2+
3+
declare(strict_types=1);
4+
5+
namespace LaunchDarkly\Migrations;
6+
7+
/**
8+
* The WriteResult pairs an origin with a result.
9+
*/
10+
class WriteResult
11+
{
12+
public function __construct(
13+
public readonly OperationResult $authoritative,
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public readonly ?OperationResult $nonauthoritative = null
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) {
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}
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}

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