Merge pull request #2198 from hashicorp/f-keys-values

core: keys() and values() funcs for map variables

config/interpolate_funcs.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -278,3 +279,73 @@ func interpolationFuncElement() ast.Function {
 		},
 	}
 }
+
+// interpolationFuncKeys implements the "keys" function that yields a list of
+// keys of map types within a Terraform configuration.
+func interpolationFuncKeys(vs map[string]ast.Variable) ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeString},
+		ReturnType: ast.TypeString,
+		Callback: func(args []interface{}) (interface{}, error) {
+			// Prefix must include ending dot to be a map
+			prefix := fmt.Sprintf("var.%s.", args[0].(string))
+			keys := make([]string, 0, len(vs))
+			for k, _ := range vs {
+				if !strings.HasPrefix(k, prefix) {
+					continue
+				}
+				keys = append(keys, k[len(prefix):])
+			}
+
+			if len(keys) <= 0 {
+				return "", fmt.Errorf(
+					"failed to find map '%s'",
+					args[0].(string))
+			}
+
+			sort.Strings(keys)
+
+			return strings.Join(keys, InterpSplitDelim), nil
+		},
+	}
+}
+
+// interpolationFuncValues implements the "values" function that yields a list of
+// keys of map types within a Terraform configuration.
+func interpolationFuncValues(vs map[string]ast.Variable) ast.Function {
+	return ast.Function{
+		ArgTypes:   []ast.Type{ast.TypeString},
+		ReturnType: ast.TypeString,
+		Callback: func(args []interface{}) (interface{}, error) {
+			// Prefix must include ending dot to be a map
+			prefix := fmt.Sprintf("var.%s.", args[0].(string))
+			keys := make([]string, 0, len(vs))
+			for k, _ := range vs {
+				if !strings.HasPrefix(k, prefix) {
+					continue
+				}
+				keys = append(keys, k)
+			}
+
+			if len(keys) <= 0 {
+				return "", fmt.Errorf(
+					"failed to find map '%s'",
+					args[0].(string))
+			}
+
+			sort.Strings(keys)
+
+			vals := make([]string, 0, len(keys))
+
+			for _, k := range keys {
+				v := vs[k]
+				if v.Type != ast.TypeString {
+					return "", fmt.Errorf("values(): %q has bad type %s", k, v.Type)
+				}
+				vals = append(vals, vs[k].Value.(string))
+			}
+
+			return strings.Join(vals, InterpSplitDelim), nil
+		},
+	}
+}

config/interpolate_funcs_test.go

@@ -384,6 +384,104 @@ func TestInterpolateFuncLookup(t *testing.T) {
 	})
 }
 
+func TestInterpolateFuncKeys(t *testing.T) {
+	testFunction(t, testFunctionConfig{
+		Vars: map[string]ast.Variable{
+			"var.foo.bar": ast.Variable{
+				Value: "baz",
+				Type:  ast.TypeString,
+			},
+			"var.foo.qux": ast.Variable{
+				Value: "quack",
+				Type:  ast.TypeString,
+			},
+			"var.str": ast.Variable{
+				Value: "astring",
+				Type:  ast.TypeString,
+			},
+		},
+		Cases: []testFunctionCase{
+			{
+				`${keys("foo")}`,
+				fmt.Sprintf(
+					"bar%squx",
+					InterpSplitDelim),
+				false,
+			},
+
+			// Invalid key
+			{
+				`${keys("not")}`,
+				nil,
+				true,
+			},
+
+			// Too many args
+			{
+				`${keys("foo", "bar")}`,
+				nil,
+				true,
+			},
+
+			// Not a map
+			{
+				`${keys("str")}`,
+				nil,
+				true,
+			},
+		},
+	})
+}
+
+func TestInterpolateFuncValues(t *testing.T) {
+	testFunction(t, testFunctionConfig{
+		Vars: map[string]ast.Variable{
+			"var.foo.bar": ast.Variable{
+				Value: "quack",
+				Type:  ast.TypeString,
+			},
+			"var.foo.qux": ast.Variable{
+				Value: "baz",
+				Type:  ast.TypeString,
+			},
+			"var.str": ast.Variable{
+				Value: "astring",
+				Type:  ast.TypeString,
+			},
+		},
+		Cases: []testFunctionCase{
+			{
+				`${values("foo")}`,
+				fmt.Sprintf(
+					"quack%sbaz",
+					InterpSplitDelim),
+				false,
+			},
+
+			// Invalid key
+			{
+				`${values("not")}`,
+				nil,
+				true,
+			},
+
+			// Too many args
+			{
+				`${values("foo", "bar")}`,
+				nil,
+				true,
+			},
+
+			// Not a map
+			{
+				`${values("str")}`,
+				nil,
+				true,
+			},
+		},
+	})
+}
+
 func TestInterpolateFuncElement(t *testing.T) {
 	testFunction(t, testFunctionConfig{
 		Cases: []testFunctionCase{

config/raw_config.go

@@ -304,6 +304,8 @@ func langEvalConfig(vs map[string]ast.Variable) *lang.EvalConfig {
 		funcMap[k] = v
 	}
 	funcMap["lookup"] = interpolationFuncLookup(vs)
+	funcMap["keys"] = interpolationFuncKeys(vs)
+	funcMap["values"] = interpolationFuncValues(vs)
 
 	return &lang.EvalConfig{
 		GlobalScope: &ast.BasicScope{