package templater import ( "bytes" "encoding/json" "fmt" "io/ioutil" "os" "path" "strings" "text/template" "github.com/Masterminds/sprig" "github.com/polydawn/meep" "github.com/tazjin/kontemplate/context" ) // Error that is caused by non-existent template files being specified type TemplateNotFoundError struct { meep.AllTraits Name string } // Error that is caused during templating, e.g. required value being absent or invalid template format type TemplatingError struct { meep.AllTraits } func LoadAndPrepareTemplates(include *[]string, exclude *[]string, c *context.Context) (output []string, err error) { limitedResourceSets := applyLimits(&c.ResourceSets, include, exclude) for _, rs := range *limitedResourceSets { err = processResourceSet(c, &rs, &output) if err != nil { return } } return } func processResourceSet(c *context.Context, rs *context.ResourceSet, output *[]string) error { fmt.Fprintf(os.Stderr, "Loading resources for %s\n", rs.Name) rp := path.Join(c.BaseDir, rs.Name) files, err := ioutil.ReadDir(rp) err = processFiles(c, rs, rp, files, output) if err != nil { return meep.New( &TemplateNotFoundError{Name: rs.Name}, meep.Cause(err), ) } return nil } func processFiles(c *context.Context, rs *context.ResourceSet, rp string, files []os.FileInfo, output *[]string) error { for _, file := range files { if !file.IsDir() && isResourceFile(file) { p := path.Join(rp, file.Name()) o, err := templateFile(c, rs, p) if err != nil { return err } *output = append(*output, o) } } return nil } func templateFile(c *context.Context, rs *context.ResourceSet, filename string) (string, error) { tpl, err := template.New(path.Base(filename)).Funcs(templateFuncs()).ParseFiles(filename) if err != nil { return "", meep.New( &TemplateNotFoundError{Name: filename}, meep.Cause(err), ) } var b bytes.Buffer // Guard against empty map before merging keys if rs.Values == nil { rs.Values = make(map[string]interface{}, 0) } // Merge global and resourceset-specific values (don't override from global) for k, v := range c.Global { if _, ok := rs.Values[k]; !ok { rs.Values[k] = v } } err = tpl.Execute(&b, rs.Values) if err != nil { return "", meep.New( &TemplatingError{}, meep.Cause(err), ) } return b.String(), nil } // Applies the limits of explicitly included or excluded resources and returns the updated resource set. // Exclude takes priority over include func applyLimits(rs *[]context.ResourceSet, include *[]string, exclude *[]string) *[]context.ResourceSet { if len(*include) == 0 && len(*exclude) == 0 { return rs } // Exclude excluded resource sets excluded := make([]context.ResourceSet, 0) for _, r := range *rs { if !matchesResourceSet(exclude, &r) { excluded = append(excluded, r) } } // Include included resource sets if len(*include) == 0 { return &excluded } included := make([]context.ResourceSet, 0) for _, r := range excluded { if matchesResourceSet(include, &r) { included = append(included, r) } } return &included } // Check whether an include/exclude string slice matches a resource set func matchesResourceSet(s *[]string, rs *context.ResourceSet) bool { for _, r := range *s { if r == rs.Name || r == *rs.Parent { return true } } return false } func templateFuncs() template.FuncMap { m := sprig.TxtFuncMap() m["json"] = func(data interface{}) string { b, _ := json.Marshal(data) return string(b) } return m } // Checks whether a file is a resource file (i.e. is YAML or JSON) func isResourceFile(f os.FileInfo) bool { return strings.HasSuffix(f.Name(), "yaml") || strings.HasSuffix(f.Name(), "yml") || strings.HasSuffix(f.Name(), "json") }