[2.x] In-cluster configuration for Pod-based apps

.github/workflows/ci.yml

@@ -71,6 +71,14 @@ jobs:
         composer require "laravel/framework:${{ matrix.laravel }}" "orchestra/testbench:${{ matrix.testbench }}" --no-interaction --no-update
         composer update --${{ matrix.prefer }} --prefer-dist --no-interaction --no-suggest
 
+    - name: Setup in-cluster config
+      run: |
+        sudo mkdir -p /var/run/secrets/kubernetes.io/serviceaccount
+        echo "some-token" | sudo tee /var/run/secrets/kubernetes.io/serviceaccount/token
+        echo "c29tZS1jZXJ0Cg==" | sudo tee /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
+        echo "some-namespace" | sudo tee /var/run/secrets/kubernetes.io/serviceaccount/namespace
+        sudo chmod -R 777 /var/run/secrets/kubernetes.io/serviceaccount/
+
     - name: Run tests
       run: |
         vendor/bin/phpunit --coverage-text --coverage-clover=coverage.xml

docs/Cluster.md

@@ -51,3 +51,21 @@ For testing purposes or local checkups, you can disable SSL checks:
 ```php
 $cluster->withoutSslChecks();
 ```
+
+## In-Cluster Configuration
+
+Kubernetes allows Pods to access [the internal kubeapi within a container](https://kubernetes.io/docs/tasks/run-application/access-api-from-pod/).
+
+PhpK8s allows you to set up an in-cluster-ready client with minimal configuration. Please keep in mind that this works only within pods that run in a Kubernetes cluster.
+
+```php
+use RenokiCo\PhpK8s\KubernetesCluster;
+
+$cluster = new KubernetesCluster('https://kubernetes.default.svc');
+
+$cluster->inClusterConfiguration();
+
+foreach ($cluster->getAllServices() as $svc) {
+    //
+}
+```

src/KubernetesCluster.php

@@ -19,13 +19,6 @@ class KubernetesCluster
      */
     protected $url;
 
-    /**
-     * The API port.
-     *
-     * @var int
-     */
-    protected $port = 8080;
-
     /**
      * The class name for the K8s resource.
      *

src/Traits/Cluster/AuthenticatesCluster.php

@@ -2,6 +2,8 @@
 
 namespace RenokiCo\PhpK8s\Traits\Cluster;
 
+use RenokiCo\PhpK8s\Kinds\K8sResource;
+
 trait AuthenticatesCluster
 {
     /**
@@ -52,7 +54,7 @@ trait AuthenticatesCluster
      */
     public function withToken(string $token = null)
     {
-        $this->token = str_replace(["\r", "\n"], '', $token);
+        $this->token = $this->normalize($token);
 
         return $this;
     }
@@ -134,4 +136,39 @@ public function withoutSslChecks()
 
         return $this;
     }
+
+    /**
+     * Load the in-cluster configuration to run the code
+     * under a Pod in a cluster.
+     *
+     * @return $this
+     */
+    public function inClusterConfiguration()
+    {
+        if (file_exists($tokenPath = '/var/run/secrets/kubernetes.io/serviceaccount/token')) {
+            $this->loadTokenFromFile($tokenPath);
+        }
+
+        if (file_exists($caPath = '/var/run/secrets/kubernetes.io/serviceaccount/ca.crt')) {
+            $this->withCaCertificate($caPath);
+        }
+
+        if ($namespace = @file_get_contents('/var/run/secrets/kubernetes.io/serviceaccount/namespace')) {
+            K8sResource::setDefaultNamespace($this->normalize($namespace));
+        }
+
+        return $this;
+    }
+
+    /**
+     * Replace \r and \n with nothing. Used to read
+     * strings from files that might contain extra chars.
+     *
+     * @param  string  $content
+     * @return string
+     */
+    protected function normalize(string $content): string
+    {
+        return str_replace(["\r", "\n"], '', $content);
+    }
 }

tests/KubeConfigTest.php

@@ -5,6 +5,7 @@
 use RenokiCo\PhpK8s\Exceptions\KubeConfigClusterNotFound;
 use RenokiCo\PhpK8s\Exceptions\KubeConfigContextNotFound;
 use RenokiCo\PhpK8s\Exceptions\KubeConfigUserNotFound;
+use RenokiCo\PhpK8s\Kinds\K8sResource;
 use RenokiCo\PhpK8s\KubernetesCluster;
 
 class KubeConfigTest extends TestCase
@@ -21,13 +22,15 @@ public function setUp(): void
 
     public function test_kube_config_from_yaml_file_with_base64_encoded_ssl()
     {
-        $this->cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube');
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
+        $cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube');
 
         [
             'verify' => $caPath,
             'cert' => $certPath,
             'ssl_key' => $keyPath,
-        ] = $this->cluster->getClient()->getConfig();
+        ] = $cluster->getClient()->getConfig();
 
         $this->assertEquals("some-ca\n", file_get_contents($caPath));
         $this->assertEquals("some-cert\n", file_get_contents($certPath));
@@ -36,13 +39,15 @@ public function test_kube_config_from_yaml_file_with_base64_encoded_ssl()
 
     public function test_kube_config_from_yaml_file_with_paths_to_ssl()
     {
-        $this->cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube-2');
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
+        $cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube-2');
 
         [
             'verify' => $caPath,
             'cert' => $certPath,
             'ssl_key' => $keyPath,
-        ] = $this->cluster->getClient()->getConfig();
+        ] = $cluster->getClient()->getConfig();
 
         $this->assertEquals('/path/to/.minikube/ca.crt', $caPath);
         $this->assertEquals('/path/to/.minikube/client.crt', $certPath);
@@ -51,40 +56,68 @@ public function test_kube_config_from_yaml_file_with_paths_to_ssl()
 
     public function test_kube_config_from_yaml_cannot_load_if_no_cluster()
     {
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
         $this->expectException(KubeConfigClusterNotFound::class);
 
-        $this->cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube-without-cluster');
+        $cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube-without-cluster');
     }
 
     public function test_kube_config_from_yaml_cannot_load_if_no_user()
     {
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
         $this->expectException(KubeConfigUserNotFound::class);
 
-        $this->cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube-without-user');
+        $cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'minikube-without-user');
     }
 
     public function test_kube_config_from_yaml_cannot_load_if_wrong_context()
     {
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
         $this->expectException(KubeConfigContextNotFound::class);
 
-        $this->cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'inexistent-context');
+        $cluster->fromKubeConfigYamlFile(__DIR__.'/cluster/kubeconfig.yaml', 'inexistent-context');
     }
 
     public function test_http_authentication()
     {
-        $this->cluster->httpAuthentication('some-user', 'some-password');
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
 
-        ['auth' => $auth] = $this->cluster->getClient()->getConfig();
+        $cluster->httpAuthentication('some-user', 'some-password');
+
+        ['auth' => $auth] = $cluster->getClient()->getConfig();
 
         $this->assertEquals(['some-user', 'some-password'], $auth);
     }
 
     public function test_bearer_token_authentication()
     {
-        $this->cluster->loadTokenFromFile(__DIR__.'/cluster/token.txt');
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
+        $cluster->loadTokenFromFile(__DIR__.'/cluster/token.txt');
 
-        ['headers' => ['authorization' => $token]] = $this->cluster->getClient()->getConfig();
+        ['headers' => ['authorization' => $token]] = $cluster->getClient()->getConfig();
 
         $this->assertEquals('Bearer some-token', $token);
     }
+
+    public function test_in_cluster_config()
+    {
+        $cluster = new KubernetesCluster('http://127.0.0.1:8080');
+
+        $cluster->inClusterConfiguration();
+
+        [
+            'headers' => ['authorization' => $token],
+            'verify' => $caPath,
+        ] = $cluster->getClient()->getConfig();
+
+        $this->assertEquals('Bearer some-token', $token);
+        $this->assertEquals('/var/run/secrets/kubernetes.io/serviceaccount/ca.crt', $caPath);
+        $this->assertEquals('some-namespace', K8sResource::$defaultNamespace);
+
+        K8sResource::setDefaultNamespace('default');
+    }
 }