launchpad.net/~rogpeppe/juju-core/500-errgo-fix@v0.0.0-20140213181702-000000002356/environs/tools/validation.go (about)

     1  // Copyright 2013 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package tools
     5  
     6  import (
     7  	"fmt"
     8  
     9  	"launchpad.net/juju-core/environs/simplestreams"
    10  	"launchpad.net/juju-core/version"
    11  )
    12  
    13  // ToolsMetadataLookupParams is used to query metadata for matching tools.
    14  type ToolsMetadataLookupParams struct {
    15  	simplestreams.MetadataLookupParams
    16  	Version string
    17  	Major   int
    18  	Minor   int
    19  }
    20  
    21  // ValidateToolsMetadata attempts to load tools metadata for the specified cloud attributes and returns
    22  // any tools versions found, or an error if the metadata could not be loaded.
    23  func ValidateToolsMetadata(params *ToolsMetadataLookupParams) ([]string, error) {
    24  	if len(params.Architectures) == 0 {
    25  		return nil, fmt.Errorf("required parameter arches not specified")
    26  	}
    27  	if len(params.Sources) == 0 {
    28  		return nil, fmt.Errorf("required parameter sources not specified")
    29  	}
    30  	if params.Version == "" && params.Major == 0 {
    31  		params.Version = version.Current.Number.String()
    32  	}
    33  	var toolsConstraint *ToolsConstraint
    34  	if params.Version == "" {
    35  		toolsConstraint = NewGeneralToolsConstraint(params.Major, params.Minor, false, simplestreams.LookupParams{
    36  			CloudSpec: simplestreams.CloudSpec{params.Region, params.Endpoint},
    37  			Series:    []string{params.Series},
    38  			Arches:    params.Architectures,
    39  		})
    40  	} else {
    41  		toolsConstraint = NewVersionedToolsConstraint(params.Version, simplestreams.LookupParams{
    42  			CloudSpec: simplestreams.CloudSpec{params.Region, params.Endpoint},
    43  			Series:    []string{params.Series},
    44  			Arches:    params.Architectures,
    45  		})
    46  	}
    47  	matchingTools, err := Fetch(params.Sources, simplestreams.DefaultIndexPath, toolsConstraint, false)
    48  	if err != nil {
    49  		return nil, err
    50  	}
    51  	if len(matchingTools) == 0 {
    52  		return nil, fmt.Errorf("no matching tools found for constraint %+v", toolsConstraint)
    53  	}
    54  	versions := make([]string, len(matchingTools))
    55  	for i, tm := range matchingTools {
    56  		vers := version.Binary{version.MustParse(tm.Version), tm.Release, tm.Arch}
    57  		versions[i] = vers.String()
    58  	}
    59  	return versions, nil
    60  }