fix bug with 2 templates, same ID, different paths

The way template configs were being tracked meant that if 2 templates
had the same content but different config otherwise, they would only use
the last config. Having more than 1 template with the same content is
rare but a user ran into it with 2 templates and the same path.

This eliminates the separate tracking of template configs and bundles
them with the templates themselves. Having a 1-1 template/config and
eliminating the separate data structure makes this area of code simpler
to understand and work with while fixing this issue.

This also fixes the TemplateConfigMapping() call which should have kept
backwards compatibility with the signature.

manager/runner.go

@@ -50,10 +50,6 @@ type Runner struct {
 	outStream, errStream io.Writer
 	inStream             io.Reader
 
-	// ctemplatesMap is a map of each template ID to the TemplateConfigs
-	// that made it.
-	ctemplatesMap map[string]*config.TemplateConfig
-
 	// templates is the list of calculated templates.
 	templates []*template.Template
 
@@ -919,7 +915,6 @@ func (r *Runner) init() error {
 
 	numTemplates := len(*r.config.Templates)
 	templates := make([]*template.Template, 0, numTemplates)
-	ctemplatesMap := make(map[string]*config.TemplateConfig)
 
 	// Iterate over each TemplateConfig, creating a new Template resource for each
 	// entry. Templates are parsed and saved, and a map of templates to their
@@ -944,14 +939,13 @@ func (r *Runner) init() error {
 			RightDelim:       rightDelim,
 			FunctionDenylist: ctmpl.FunctionDenylist,
 			SandboxPath:      config.StringVal(ctmpl.SandboxPath),
+			Config:           ctmpl,
 		})
 		if err != nil {
 			return err
 		}
 
 		templates = append(templates, tmpl)
-
-		ctemplatesMap[tmpl.ID()] = ctmpl
 	}
 
 	// Convert the map of templates (which was only used to ensure uniqueness)
@@ -964,7 +958,6 @@ func (r *Runner) init() error {
 	r.renderedCh = make(chan struct{}, 1)
 	r.renderEventCh = make(chan struct{}, 1)
 
-	r.ctemplatesMap = ctemplatesMap
 	r.inStream = os.Stdin
 	r.outStream = os.Stdout
 	r.errStream = os.Stderr
@@ -1017,18 +1010,22 @@ func (r *Runner) diffAndUpdateDeps(depsMap map[string]dep.Dependency) {
 
 // TemplateConfigFor returns the TemplateConfig for the given Template
 func (r *Runner) templateConfigFor(tmpl *template.Template) *config.TemplateConfig {
-	return r.ctemplatesMap[tmpl.ID()]
+	return tmpl.Config()
 }
 
 // TemplateConfigMapping returns a mapping between the template ID and the set
 // of TemplateConfig represented by the template ID
-func (r *Runner) TemplateConfigMapping() map[string]*config.TemplateConfig {
+func (r *Runner) TemplateConfigMapping() map[string][]*config.TemplateConfig {
 	// this method is primarily used to support embedding consul-template
 	// in other applications (ex. Nomad)
-	m := make(map[string]*config.TemplateConfig)
+	m := make(map[string][]*config.TemplateConfig)
+
+	for _, tmpl := range r.templates {
+		m[tmpl.ID()] = []*config.TemplateConfig{}
+	}
 
-	for id, set := range r.ctemplatesMap {
-		m[id] = set
+	for _, tmpl := range r.templates {
+		m[tmpl.ID()] = append(m[tmpl.ID()], tmpl.Config())
 	}
 
 	return m

manager/runner_test.go

@@ -18,6 +18,38 @@ import (
 	"github.com/hashicorp/consul-template/template"
 )
 
+func TestRunner_initTemplates(t *testing.T) {
+
+	c := config.TestConfig(
+		&config.Config{
+			Templates: &config.TemplateConfigs{
+				&config.TemplateConfig{
+					Contents: config.String(`template`),
+				},
+				&config.TemplateConfig{
+					Contents: config.String(`template`),
+				},
+			},
+		})
+
+	r, err := NewRunner(c, true)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	confMap := r.TemplateConfigMapping()
+
+	for _, tmpl := range r.templates {
+		if _, ok := confMap[tmpl.ID()]; !ok {
+			t.Errorf("config map missing template entry")
+		}
+		if confs := confMap[tmpl.ID()]; len(confs) != len(r.templates) {
+			t.Errorf("should be %v templates, but there are %v",
+				len(r.templates), len(confs))
+		}
+	}
+}
+
 func TestRunner_Receive(t *testing.T) {
 
 	c := config.TestConfig(&config.Config{Once: true})

template/template.go

@@ -8,6 +8,7 @@ import (
 	"text/template"
 
 	"github.com/Masterminds/sprig"
+	"github.com/hashicorp/consul-template/config"
 	dep "github.com/hashicorp/consul-template/dependency"
 	"github.com/pkg/errors"
 )
@@ -61,6 +62,9 @@ type Template struct {
 	// and causes an error if a relative path tries to traverse outside that
 	// prefix.
 	sandboxPath string
+
+	// local reference to configuration for this template
+	config *config.TemplateConfig
 }
 
 // NewTemplateInput is used as input when creating the template.
@@ -94,6 +98,9 @@ type NewTemplateInput struct {
 	// and causes an error if a relative path tries to traverse outside that
 	// prefix.
 	SandboxPath string
+
+	// Config keeps local reference to config struct
+	Config *config.TemplateConfig
 }
 
 // NewTemplate creates and parses a new Consul Template template at the given
@@ -122,6 +129,7 @@ func NewTemplate(i *NewTemplateInput) (*Template, error) {
 	t.functionDenylist = i.FunctionDenylist
 	t.sandboxPath = i.SandboxPath
 	t.destination = i.Destination
+	t.config = i.Config
 
 	if i.Source != "" {
 		contents, err := ioutil.ReadFile(i.Source)
@@ -148,6 +156,11 @@ func (t *Template) Contents() string {
 	return t.contents
 }
 
+// Config returns the template's config
+func (t *Template) Config() *config.TemplateConfig {
+	return t.config
+}
+
 // Source returns the filepath source of this template.
 func (t *Template) Source() string {
 	if t.source == "" {