github.com/google/cadvisor@v0.49.1/container/containerd/namespaces/context.go (about)

     1  // Copyright 2017 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  /*
    15     Copyright The containerd Authors.
    16  
    17     Licensed under the Apache License, Version 2.0 (the "License");
    18     you may not use this file except in compliance with the License.
    19     You may obtain a copy of the License at
    20  
    21         http://www.apache.org/licenses/LICENSE-2.0
    22  
    23     Unless required by applicable law or agreed to in writing, software
    24     distributed under the License is distributed on an "AS IS" BASIS,
    25     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    26     See the License for the specific language governing permissions and
    27     limitations under the License.
    28  */
    29  
    30  package namespaces
    31  
    32  import (
    33  	"context"
    34  	"os"
    35  
    36  	"github.com/google/cadvisor/container/containerd/errdefs"
    37  	"github.com/google/cadvisor/container/containerd/identifiers"
    38  	"github.com/pkg/errors"
    39  )
    40  
    41  const (
    42  	// NamespaceEnvVar is the environment variable key name
    43  	NamespaceEnvVar = "CONTAINERD_NAMESPACE"
    44  	// Default is the name of the default namespace
    45  	Default = "default"
    46  )
    47  
    48  type namespaceKey struct{}
    49  
    50  // WithNamespace sets a given namespace on the context
    51  func WithNamespace(ctx context.Context, namespace string) context.Context {
    52  	ctx = context.WithValue(ctx, namespaceKey{}, namespace) // set our key for namespace
    53  	// also store on the grpc and ttrpc headers so it gets picked up by any clients that
    54  	// are using this.
    55  	return withTTRPCNamespaceHeader(withGRPCNamespaceHeader(ctx, namespace), namespace)
    56  }
    57  
    58  // NamespaceFromEnv uses the namespace defined in CONTAINERD_NAMESPACE or
    59  // default
    60  func NamespaceFromEnv(ctx context.Context) context.Context {
    61  	namespace := os.Getenv(NamespaceEnvVar)
    62  	if namespace == "" {
    63  		namespace = Default
    64  	}
    65  	return WithNamespace(ctx, namespace)
    66  }
    67  
    68  // Namespace returns the namespace from the context.
    69  //
    70  // The namespace is not guaranteed to be valid.
    71  func Namespace(ctx context.Context) (string, bool) {
    72  	namespace, ok := ctx.Value(namespaceKey{}).(string)
    73  	if !ok {
    74  		if namespace, ok = fromGRPCHeader(ctx); !ok {
    75  			return fromTTRPCHeader(ctx)
    76  		}
    77  	}
    78  	return namespace, ok
    79  }
    80  
    81  // NamespaceRequired returns the valid namespace from the context or an error.
    82  func NamespaceRequired(ctx context.Context) (string, error) {
    83  	namespace, ok := Namespace(ctx)
    84  	if !ok || namespace == "" {
    85  		return "", errors.Wrapf(errdefs.ErrFailedPrecondition, "namespace is required")
    86  	}
    87  	if err := identifiers.Validate(namespace); err != nil {
    88  		return "", errors.Wrap(err, "namespace validation")
    89  	}
    90  	return namespace, nil
    91  }