github.com/mattyw/juju@v0.0.0-20140610034352-732aecd63861/environs/imagemetadata/validation.go (about)

     1  // Copyright 2013 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package imagemetadata
     5  
     6  import (
     7  	"fmt"
     8  
     9  	"github.com/juju/juju/environs/simplestreams"
    10  )
    11  
    12  // ValidateImageMetadata attempts to load image metadata for the specified cloud attributes and stream
    13  // and returns any image ids found, or an error if the metadata could not be loaded.
    14  func ValidateImageMetadata(params *simplestreams.MetadataLookupParams) ([]string, *simplestreams.ResolveInfo, error) {
    15  	if params.Series == "" {
    16  		return nil, nil, fmt.Errorf("required parameter series not specified")
    17  	}
    18  	if params.Region == "" {
    19  		return nil, nil, fmt.Errorf("required parameter region not specified")
    20  	}
    21  	if params.Endpoint == "" {
    22  		return nil, nil, fmt.Errorf("required parameter endpoint not specified")
    23  	}
    24  	if len(params.Architectures) == 0 {
    25  		return nil, nil, fmt.Errorf("required parameter arches not specified")
    26  	}
    27  	if len(params.Sources) == 0 {
    28  		return nil, nil, fmt.Errorf("required parameter sources not specified")
    29  	}
    30  	imageConstraint := NewImageConstraint(simplestreams.LookupParams{
    31  		CloudSpec: simplestreams.CloudSpec{
    32  			Region:   params.Region,
    33  			Endpoint: params.Endpoint,
    34  		},
    35  		Series: []string{params.Series},
    36  		Arches: params.Architectures,
    37  		Stream: params.Stream,
    38  	})
    39  	matchingImages, resolveInfo, err := Fetch(params.Sources, simplestreams.DefaultIndexPath, imageConstraint, false)
    40  	if err != nil {
    41  		return nil, resolveInfo, err
    42  	}
    43  	if len(matchingImages) == 0 {
    44  		return nil, resolveInfo, fmt.Errorf("no matching images found for constraint %+v", imageConstraint)
    45  	}
    46  	image_ids := make([]string, len(matchingImages))
    47  	for i, im := range matchingImages {
    48  		image_ids[i] = im.Id
    49  	}
    50  	return image_ids, resolveInfo, nil
    51  }