agent/api/container/container.go
func (c *Container) InjectV3MetadataEndpoint() {
	c.lock.Lock()
	defer c.lock.Unlock()

	// don't assume that the environment variable map has been initialized by others
	if c.Environment == nil {
		c.Environment = make(map[string]string)
	}

	c.Environment[MetadataURIEnvironmentVariableName] =
		fmt.Sprintf(MetadataURIFormat, c.V3EndpointID)
}
func (c *Container) InjectV3MetadataEndpoint() {
	c.lock.Lock()
	defer c.lock.Unlock()

	// don't assume that the environment variable map has been initialized by others
	if c.Environment == nil {
		c.Environment = make(map[string]string)
	}

	c.Environment[MetadataURIEnvironmentVariableName] =
		fmt.Sprintf(MetadataURIFormat, c.V3EndpointID)
}
// InjectV3MetadataEndpoint injects the v3 metadata endpoint as an environment variable for a container