class Google::Cloud::Env
## Google
Cloud
hosting environment
This library provides access to information about the application’s hosting environment if it is running on Google
Cloud
Platform. You can use this library to determine which Google
Cloud
product is hosting your application (e.g. App Engine, Kubernetes Engine), information about the Google
Cloud
project hosting the application, information about the virtual machine instance, authentication information, and so forth.
### Usage
Obtain an instance of the environment info with:
“‘ruby require “google/cloud/env” env = Google::Cloud.env
“`
Then you can interrogate any fields using methods on the object.
“‘ruby if env.app_engine?
# App engine specific logic
end “‘
Any item that does not apply to the current environment will return nil. For example:
“‘ruby unless env.app_engine?
service = env.app_engine_service_id # => nil
end “‘
Constants
- VERSION
-
Library version @return [String]
Attributes
The compute metadata access object. Use this to make direct calls to compute metadata or configure how metadata server queries are done, or to mock out the metadata server for testing.
@return [Google::Cloud::Env::ComputeMetadata]
The compute SMBIOS access object. Use this to make direct queries for compute SMBIOS information, or to mock out the SMBIOS for testing.
@return [Google::Cloud::Env::ComputeSMBIOS]
The variables access object. Use this to make direct queries for information from the file system, or to mock out the file system for testing.
@return [Google::Cloud::Env::FileSystem]
The variables access object. Use this to make direct queries for environment variable information, or to mock out environment variables for testing.
@return [Google::Cloud::Env::Variables]
Public Class Methods
Source
# File lib/google/cloud/env.rb, line 518 def self.get ::Google::Cloud.env end
Returns the global instance of {Google::Cloud::Env}.
@return [Google::Cloud::Env]
Source
# File lib/google/cloud/env.rb, line 72 def initialize @variables = Variables.new @file_system = FileSystem.new @compute_smbios = ComputeSMBIOS.new @compute_metadata = ComputeMetadata.new variables: @variables, compute_smbios: @compute_smbios end
Create a new instance of the environment information. Most clients should not need to call this directly. Obtain a singleton instance of the information from ‘Google::Cloud.env`.
Public Instance Methods
Source
# File lib/google/cloud/env.rb, line 212 def app_engine? variables["GAE_INSTANCE"] ? true : false end
Determine whether the application is running on Google
App Engine.
@return [boolean]
Source
# File lib/google/cloud/env.rb, line 222 def app_engine_flexible? app_engine? && variables["GAE_ENV"] != "standard" end
Determine whether the application is running on Google
App Engine Flexible Environment.
@return [boolean]
Source
# File lib/google/cloud/env.rb, line 463 def app_engine_memory_mb result = variables["GAE_MEMORY_MB"] result&.to_i end
Returns the amount of memory reserved for the current App Engine instance, or ‘nil` if the current code is not running in App Engine.
@return [Integer,nil]
Source
# File lib/google/cloud/env.rb, line 442 def app_engine_service_id variables["GAE_SERVICE"] end
Returns the name of the running App Engine service, or ‘nil` if the current code is not running in App Engine.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 453 def app_engine_service_version variables["GAE_VERSION"] end
Returns the version of the running App Engine service, or ‘nil` if the current code is not running in App Engine.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 232 def app_engine_standard? app_engine? && variables["GAE_ENV"] == "standard" end
Determine whether the application is running on Google
App Engine Standard Environment.
@return [boolean]
Source
Source
# File lib/google/cloud/env.rb, line 268 def compute_engine? compute_smbios.google_compute? end
Determine whether the application is running on Google
Compute Engine.
Note that most other products (e.g. App Engine, Kubernetes Engine, Cloud
Shell) themselves use Compute Engine under the hood, so this method will return true for all the above products. If you want to determine whether the application is running on a “raw” Compute Engine VM without using a higher level hosting product, use {Env#raw_compute_engine?}.
@return [boolean]
Source
# File lib/google/cloud/env.rb, line 149 def ensure_metadata timeout: nil compute_metadata.ensure_existence timeout: timeout end
Assert that the Metadata Server should be present, and wait for a confirmed connection to ensure it is up. In general, this will run at most {ComputeMetadata::DEFAULT_WARMUP_TIME} seconds to wait out the expected maximum warmup time, but a shorter timeout can be provided.
This method is useful call during application initialization to wait for the Metadata Server to warm up and ensure that subsequent lookups should succeed.
@param timeout [Numeric,nil] a timeout in seconds, or nil to wait
until we have conclusively decided one way or the other.
@return [:confirmed] if we were able to confirm connection. @raise [MetadataServerNotResponding] if we were unable to confirm
connection with the Metadata Server, either because the timeout expired or because the server seems to be down
Source
# File lib/google/cloud/env.rb, line 409 def instance_attribute key compute_metadata.lookup "instance/attributes/#{key}" rescue MetadataServerNotResponding nil end
Returns the value of the given instance attribute for the VM instance hosting the application, or ‘nil` if the given key does not exist or application is not running on Google
Cloud
.
@param [String] key Attribute key to look up. @return [String,nil]
Source
# File lib/google/cloud/env.rb, line 394 def instance_attribute_keys result = compute_metadata.lookup "instance/attributes/" result&.split rescue MetadataServerNotResponding nil end
Returns an array (which may be empty) of all attribute keys present for the VM instance hosting the application, or ‘nil` if the application is not running on Google
Cloud
.
@return [Array<String>,nil]
Source
# File lib/google/cloud/env.rb, line 340 def instance_description compute_metadata.lookup "instance/description" rescue MetadataServerNotResponding nil end
Returns the description field (which may be the empty string) of the VM instance hosting the application, or ‘nil` if the application is not running on Google
Cloud
.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 366 def instance_machine_type result = compute_metadata.lookup "instance/machine-type" result&.split("/")&.last rescue MetadataServerNotResponding nil end
Returns the machine type of the VM instance hosting the application, or ‘nil` if the application is not running on Google
Cloud
.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 327 def instance_name variables["GAE_INSTANCE"] || compute_metadata.lookup("instance/name") rescue MetadataServerNotResponding nil end
Returns the name of the VM instance hosting the application, or ‘nil` if the application is not running on Google
Cloud
.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 353 def instance_zone result = compute_metadata.lookup "instance/zone" result&.split("/")&.last rescue MetadataServerNotResponding nil end
Returns the zone (for example “‘us-central1-c`”) in which the instance hosting the application lives. Returns `nil` if the application is not running on Google
Cloud
.
@return [String,nil]
Source
Source
# File lib/google/cloud/env.rb, line 421 def knative_service_id variables["K_SERVICE"] end
Returns the name of the running Knative service, or ‘nil` if the current code is not running on Knative.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 432 def knative_service_revision variables["K_REVISION"] end
Returns the revision of the running Knative service, or ‘nil` if the current code is not running on Knative.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 242 def kubernetes_engine? kubernetes_engine_cluster_name ? true : false end
Determine whether the application is running on Google
Kubernetes Engine (GKE).
@return [boolean]
Source
# File lib/google/cloud/env.rb, line 475 def kubernetes_engine_cluster_name instance_attribute "cluster-name" rescue MetadataServerNotResponding nil end
Returns the name of the Kubernetes Engine cluster hosting the application, or ‘nil` if the current code is not running in Kubernetes Engine.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 489 def kubernetes_engine_namespace_id # The Kubernetes namespace is difficult to obtain without help from # the application using the Downward API. The environment variable # below is set in some older versions of GKE, and the file below is # present in Kubernetes as of version 1.9, but it is possible that # alternatives will need to be found in the future. variables["GKE_NAMESPACE_ID"] || file_system.read("/var/run/secrets/kubernetes.io/serviceaccount/namespace") end
Returns the name of the Kubernetes Engine namespace hosting the application, or ‘nil` if the current code is not running in Kubernetes Engine.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 509 def logging_agent_expected? compute_engine? && !cloud_shell? && (app_engine? || knative? || kubernetes_engine?) end
Determine whether the application is running in an environment where a Google
Cloud
logging agent is expected to be running. In such an environment, we expect that the standard output and error streams are likely to be parsed by the logging agent and log entries are written to the Google
Cloud
Logging service.
@return [boolean]
Source
# File lib/google/cloud/env.rb, line 170 def lookup_metadata type, entry, query: nil compute_metadata.lookup "#{type}/#{entry}", query: query end
Retrieve info from the Google
Compute Engine Metadata Service. Returns ‘nil` if the given data is not present.
@param [String] type Type of metadata to look up. Currently supported
values are "project" and "instance".
@param [String] entry Metadata entry path to look up. @param query [Hash{String => String}] Any additional query parameters
to send with the request.
@return [String] the data @return [nil] if there is no data for the specified type and entry @raise [MetadataServerNotResponding] if the Metadata Server is not
responding. This could either be because the metadata service is not present in the current environment, or if it is expected to be present but is overloaded or has not finished initializing.
Source
# File lib/google/cloud/env.rb, line 193 def lookup_metadata_response type, entry, query: nil compute_metadata.lookup_response "#{type}/#{entry}", query: query end
Retrieve an HTTP response from the Google
Compute Engine Metadata Service. Returns a {ComputeMetadata::Response} with a status code, data, and headers. The response could be 200 for success, 404 if the given entry is not present, or other HTTP result code for authorization or other errors.
@param [String] type Type of metadata to look up. Currently supported
values are "project" and "instance".
@param [String] entry Metadata entry path to look up. @param query [Hash{String => String}] Any additional query parameters
to send with the request.
@return [Google::Cloud::Env::ComputeMetadata::Response] the response @raise [MetadataServerNotResponding] if the Metadata Server is not
responding. This could either be because the metadata service is not present in the current environment, or if it is expected to be present but is overloaded or has not finished initializing.
Source
# File lib/google/cloud/env.rb, line 128 def metadata? compute_metadata.check_existence == :confirmed end
Determine whether the Google
Compute Engine Metadata Service is running.
This method is conservative. It may block for a short period (up to about 1.5 seconds) while attempting to contact the server, but if this fails, this method will return false, even though it is possible that a future call could succeed. In particular, this might happen in environments where there is a warmup time for the Metadata Server. Early calls before the Server has warmed up may return false, while later calls return true.
@return [boolean]
Source
# File lib/google/cloud/env.rb, line 306 def numeric_project_id # CloudShell's metadata server seems to run in a dummy project. # We can get the user's normal project ID via environment variables, # but the numeric ID from the metadata service is not correct. So # disable this for CloudShell to avoid confusion. return nil if cloud_shell? result = begin compute_metadata.lookup "project/numeric-project-id" rescue MetadataServerNotResponding nil end result&.to_i end
Returns the unique numeric ID of the project hosting the application, or ‘nil` if the application is not running on Google
Cloud
.
Caveat: this method does not work and returns ‘nil` on CloudShell.
@return [Integer,nil]
Source
# File lib/google/cloud/env.rb, line 289 def project_id variables["GOOGLE_CLOUD_PROJECT"] || variables["GCLOUD_PROJECT"] || variables["DEVSHELL_PROJECT_ID"] || compute_metadata.lookup("project/project-id") rescue MetadataServerNotResponding nil end
Returns the unique string ID of the project hosting the application, or ‘nil` if the application is not running on Google
Cloud
.
@return [String,nil]
Source
# File lib/google/cloud/env.rb, line 279 def raw_compute_engine? compute_engine? && !knative? && !app_engine? && !cloud_shell? && !kubernetes_engine? end
Determine whether the application is running on “raw” Google
Compute Engine without using a higher level hosting product such as App Engine or Kubernetes Engine.
@return [boolean]