Merge pull request #49 from JimLarson/first-cel-service

CelService server for cel-go.

Use Go proto libraries exported from cel-spec.

Note that we use a different Go package for the google.rpc.Status message
than is specified in its .proto file.  We do this to avoid a different
and incompatible Go proto library that is brought in by the Bazel rules.
We will revert to the right package when this bug is fixed.
See bazel-contrib/rules_go#1530

Expand common.Source to subsume interpreter.Metadata, for the latter's
eventual deprecation, and to allow the checker inputs to be constructed
without access to the source text.

Introduce a specialized traits.Lister for arrays of ref.Value values.

Implement CelService server and tests.  Includes conversion between
ref.Value types and protos.

README.md

@@ -69,10 +69,10 @@ if len(errors.GetErrors()) != 0 {
 // package (empty string):
 typeProvider := types.NewProvider()
 env := checker.NewStandardEnv(packages.DefaultPackage, typeProvider, errors)
-env.Add(decls.NewIdent("a", decls.Bool),
-    decls.NewIdent("b", decls.Bool),
-    decls.NewIdent("c", decls.NewListType(decls.Int)))
-c := checker.Check(p, env, "") 
+env.Add(decls.NewIdent("a", decls.Bool, nil),
+    decls.NewIdent("b", decls.Bool, nil),
+    decls.NewIdent("c", decls.NewListType(decls.Int), nil))
+c := checker.Check(p, env, "")
 if len(errors.GetErrors()) != 0 {
     return nil, fmt.Error(errors.ToDisplayString()))
 }
@@ -106,4 +106,4 @@ Disclaimer: This is not an official Google product.
 [3]:  https://github.com/google/cel-cpp
 [4]:  https://github.com/google/cel-go/issues
 [5]:  https://bazel.build
-[6]:  https://godoc.org/github.com/google/cel-go
+[6]:  https://godoc.org/github.com/google/cel-go

WORKSPACE

@@ -18,6 +18,50 @@ go_repository(
 
 git_repository(
   name = "com_google_cel_spec",
-  commit = "3769a0b59441e6a2ebe747154dd1a4c85ce65ae0",
+  commit = "3c25c4d4ffb504e2c24c1d84196c78ba3ac9e612",
   remote = "https://github.com/google/cel-spec.git",
 )
+
+new_http_archive(
+    name = "com_google_googleapis",
+    url = "https://github.com/googleapis/googleapis/archive/common-protos-1_3_1.zip",
+    strip_prefix = "googleapis-common-protos-1_3_1/",
+    build_file_content = """
+load('@io_bazel_rules_go//proto:def.bzl', 'go_proto_library')
+
+proto_library(
+    name = 'rpc_status',
+    srcs = ['google/rpc/status.proto'],
+    deps = [
+        '@com_google_protobuf//:any_proto',
+        '@com_google_protobuf//:empty_proto'
+    ],
+    visibility = ['//visibility:public'],
+)
+
+go_proto_library(
+    name = 'rpc_status_go_proto',
+    # TODO: Switch to the correct import path when bazel rules fixed.
+    #importpath = 'google.golang.org/genproto/googleapis/rpc/status',
+    importpath = 'github.com/googleapis/googleapis/google/rpc',
+    proto = ':rpc_status',
+    visibility = ['//visibility:public'],
+)
+"""
+)
+
+git_repository(
+  name = "org_pubref_rules_protobuf",
+  remote = "https://github.com/pubref/rules_protobuf",
+  tag = "v0.8.2",
+)
+
+load("@org_pubref_rules_protobuf//go:rules.bzl", "go_proto_repositories")
+go_proto_repositories()
+
+go_repository(
+  name = "org_golang_google_grpc",
+  importpath = "google.golang.org/grpc",
+  tag = "v1.11.3",
+  remote = "https://github.com/grpc/grpc-go.git",
+)

checker/BUILD.bazel

@@ -20,10 +20,10 @@ go_library(
         "//common/packages:go_default_library",
         "//common/types:go_default_library",
         "//common/types/ref:go_default_library",
-        "//io:checked_proto",
-        "//io:syntax_proto",
         "//parser:go_default_library",
         "@com_github_golang_protobuf//proto:go_default_library",
+        "@com_google_cel_spec//proto/checked/v1:checked_go_proto",
+        "@com_google_cel_spec//proto/v1:syntax_go_proto",
         "@io_bazel_rules_go//proto/wkt:empty_go_proto",
         "@io_bazel_rules_go//proto/wkt:struct_go_proto",
     ],

checker/decls/BUILD.bazel

@@ -7,8 +7,8 @@ go_library(
         "scopes.go",
     ],
     deps = [
-        "//io:checked_proto",
-        "//io:syntax_proto",
+        "@com_google_cel_spec//proto/checked/v1:checked_go_proto",
+        "@com_google_cel_spec//proto/v1:syntax_go_proto",
         "@io_bazel_rules_go//proto/wkt:empty_go_proto",
         "@io_bazel_rules_go//proto/wkt:struct_go_proto",
     ],

common/BUILD.bazel

@@ -9,6 +9,9 @@ go_library(
         "source.go",
     ],
     importpath = "github.com/google/cel-go/common",
+    deps = [
+        "@com_google_cel_spec//proto/v1:syntax_go_proto",
+    ],
     visibility = ["//visibility:public"],
 )
 

common/debug/BUILD.bazel

@@ -9,6 +9,6 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//common:go_default_library",
-        "//io:syntax_proto",
+        "@com_google_cel_spec//proto/v1:syntax_go_proto",
     ],
 )

common/source.go

@@ -16,6 +16,8 @@ package common
 
 import (
 	"strings"
+
+	"github.com/google/cel-spec/proto/v1/syntax"
 )
 
 // Source interface for filter source contents.
@@ -35,26 +37,37 @@ type Source interface {
 	// The raw character offset at which the a location exists given the
 	// location line and column.
 	// Returns the line offset and whether the location was found.
-	CharacterOffset(location Location) (int32, bool)
+	LocationOffset(location Location) (int32, bool)
 
-	// LocationFromOffset translates a raw character offset to a Location, or
+	// OffsetLocation translates a character offset to a Location, or
 	// false if the conversion was not feasible.
-	LocationFromOffset(offset int32) (Location, bool)
+	OffsetLocation(offset int32) (Location, bool)
 
-	// Return a line of content from the source and whether the line was found.
+	// Return a line of content and whether the line was found.
 	Snippet(line int) (string, bool)
-}
 
-// Ensure the StringSource implements the Source interface.
-var _ Source = &StringSource{}
+	// IdOffset returns the raw character offset of an expression within
+	// the source, or false if the expression cannot be found.
+	IdOffset(exprId int64) (int32, bool)
 
-// StringSource type implementation of the Source interface.
-type StringSource struct {
+	// IdLocation returns a Location for the given expression id,
+	// or false if one cannot be found.  It behaves as the obvious
+	// composition of IdOffset() and OffsetLocation().
+	IdLocation(exprId int64) (Location, bool)
+}
+
+// The sourceImpl type implementation of the Source interface.
+type sourceImpl struct {
 	contents    string
 	description string
 	lineOffsets []int32
+	idOffsets   map[int64]int32
 }
 
+// TODO(jimlarson) "Character offsets" should index the code points
+// within the UTF-8 encoded string.  It currently indexes bytes.
+// Can be accomplished by using rune[] instead of string for contents.
+
 // Create a new Source given the string contents and description.
 func NewStringSource(contents string, description string) Source {
 	// Compute line offsets up front as they are referred to frequently.
@@ -65,49 +78,78 @@ func NewStringSource(contents string, description string) Source {
 		offset = offset + int32(len(line)) + 1
 		offsets[int32(i)] = offset
 	}
-	return &StringSource{
+	return &sourceImpl{
 		contents:    contents,
 		description: description,
 		lineOffsets: offsets,
+		idOffsets:   map[int64]int32{},
 	}
 }
 
-func (s *StringSource) Content() string {
+func NewInfoSource(info *syntax.SourceInfo) Source {
+	return &sourceImpl{
+		contents:    "",
+		description: info.Location,
+		lineOffsets: info.LineOffsets,
+		idOffsets:   info.Positions,
+	}
+}
+
+func (s *sourceImpl) Content() string {
 	return s.contents
 }
 
-func (s *StringSource) Description() string {
+func (s *sourceImpl) Description() string {
 	return s.description
 }
 
-func (s *StringSource) LineOffsets() []int32 {
+func (s *sourceImpl) LineOffsets() []int32 {
 	return s.lineOffsets
 }
 
-func (s *StringSource) CharacterOffset(location Location) (int32, bool) {
+func (s *sourceImpl) LocationOffset(location Location) (int32, bool) {
 	if lineOffset, found := s.findLineOffset(location.Line()); found {
 		return lineOffset + int32(location.Column()), true
 	}
 	return -1, false
 }
 
-func (s *StringSource) LocationFromOffset(offset int32) (Location, bool) {
+func (s *sourceImpl) OffsetLocation(offset int32) (Location, bool) {
 	line, lineOffset := s.findLine(offset)
 	return NewLocation(int(line), int(offset-lineOffset)), true
 }
 
-func (s *StringSource) Snippet(line int) (string, bool) {
-	if charStart, found := s.findLineOffset(line); found {
-		charEnd, found := s.findLineOffset(line + 1)
-		if found {
-			return s.contents[charStart : charEnd-1], true
+func (s *sourceImpl) Snippet(line int) (string, bool) {
+	charStart, found := s.findLineOffset(line)
+	if !found || len(s.contents) == 0 {
+		return "", false
+	}
+	charEnd, found := s.findLineOffset(line + 1)
+	if found {
+		return s.contents[charStart : charEnd-1], true
+	}
+	return s.contents[charStart:], true
+}
+
+func (s *sourceImpl) IdOffset(exprId int64) (int32, bool) {
+	if offset, found := s.idOffsets[exprId]; found {
+		return offset, true
+	}
+	return -1, false
+}
+
+func (s *sourceImpl) IdLocation(exprId int64) (Location, bool) {
+	if offset, found := s.IdOffset(exprId); found {
+		if location, found := s.OffsetLocation(offset); found {
+			return location, true
 		}
-		return s.contents[charStart:], true
 	}
-	return "", false
+	return NewLocation(1, 0), false
 }
 
-func (s *StringSource) findLineOffset(line int) (int32, bool) {
+// findLineOffset returns the offset where the (1-indexed) line begins,
+// or false if line doesn't exist.
+func (s *sourceImpl) findLineOffset(line int) (int32, bool) {
 	if line == 1 {
 		return 0, true
 	} else if line > 1 && line <= int(len(s.lineOffsets)) {
@@ -117,7 +159,11 @@ func (s *StringSource) findLineOffset(line int) (int32, bool) {
 	return -1, false
 }
 
-func (s *StringSource) findLine(characterOffset int32) (int32, int32) {
+// findLine finds the line that contains the given character offset and
+// returns the line number and offset of the beginning of that line.
+// Note that the last line is treated as if it contains all offsets
+// beyond the end of the actual source.
+func (s *sourceImpl) findLine(characterOffset int32) (int32, int32) {
 	var line int32 = 1
 	for _, lineOffset := range s.lineOffsets {
 		if lineOffset > characterOffset {

common/source_test.go

@@ -54,9 +54,9 @@ func TestStringSource_Description(t *testing.T) {
 	}
 }
 
-// TestStringSource_CharacterOffset make sure that the offsets accurately reflect
+// TestStringSource_LocationOffset make sure that the offsets accurately reflect
 // the location of a character in source.
-func TestStringSource_CharacterOffset(t *testing.T) {
+func TestStringSource_LocationOffset(t *testing.T) {
 	contents := "c.d &&\n\t b.c.arg(10) &&\n\t test(10)"
 	source := NewStringSource(contents, "offset-test")
 	expectedLineOffsets := []int32{7, 24, 35}
@@ -73,14 +73,14 @@ func TestStringSource_CharacterOffset(t *testing.T) {
 	}
 	// Ensure that selecting a set of characters across multiple lines works as
 	// expected.
-	charStart, _ := source.CharacterOffset(NewLocation(1, 2))
-	charEnd, _ := source.CharacterOffset(NewLocation(3, 2))
+	charStart, _ := source.LocationOffset(NewLocation(1, 2))
+	charEnd, _ := source.LocationOffset(NewLocation(3, 2))
 	if "d &&\n\t b.c.arg(10) &&\n\t " != string(contents[charStart:charEnd]) {
 		t.Errorf(unexpectedValue, t.Name(),
 			string(contents[charStart:charEnd]),
 			"d &&\n\t b.c.arg(10) &&\n\t ")
 	}
-	if _, found := source.CharacterOffset(NewLocation(4, 0)); found {
+	if _, found := source.LocationOffset(NewLocation(4, 0)); found {
 		t.Error("Character offset was out of range of source, but still found.")
 	}
 }

common/types/BUILD.bazel

@@ -35,7 +35,7 @@ go_library(
         "//common/types/ref:go_default_library",
         "//common/types/pb:go_default_library",
         "//common/types/traits:go_default_library",
-        "//io:checked_proto",
+        "@com_google_cel_spec//proto/checked/v1:checked_go_proto",
         "@com_github_golang_protobuf//proto:go_default_library",
         "@com_github_golang_protobuf//ptypes:go_default_library",
         "@io_bazel_rules_go//proto/wkt:any_go_proto",
@@ -68,11 +68,11 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//common/types/ref:go_default_library",
-        "//io:syntax_proto",
         "//test:go_default_library",
+        "@com_google_cel_spec//proto/v1:syntax_go_proto",
         "@com_github_golang_protobuf//jsonpb:go_default_library",
         "@io_bazel_rules_go//proto/wkt:any_go_proto",
         "@io_bazel_rules_go//proto/wkt:duration_go_proto",
         "@io_bazel_rules_go//proto/wkt:timestamp_go_proto",
     ],
-)
+)