Core skeleton

.gitignore

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+.idea

cmd/protoc-gen-api_lint/main.go

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+package main
+
+import (
+	"context"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+
+	"github.com/golang/protobuf/v2/proto"
+	"github.com/golang/protobuf/v2/reflect/protodesc"
+	"github.com/golang/protobuf/v2/reflect/protoreflect"
+	"github.com/golang/protobuf/v2/reflect/protoregistry"
+	pluginpb "github.com/golang/protobuf/v2/types/plugin"
+	"github.com/jgeewax/api-linter/lint"
+	"github.com/jgeewax/api-linter/rules"
+)
+
+func main() {
+	rules := rules.Rules()
+	log.Printf("Number of rules: %d\n", len(rules.AllRules()))
+	linter := newLinter(*rules)
+	linter.run()
+}
+
+type linter struct {
+	reader io.Reader
+	writer io.Writer
+	rules  lint.Rules
+}
+
+func (l linter) run() {
+	request := readLintRequest(l.reader)
+	response, err := lint.Run(l.rules, request)
+	if err != nil {
+		log.Fatalf("Error when running lint: %v", err)
+	}
+	log.Printf("Total number of API-Linter findings: %d", len(response.Problems))
+	for _, problem := range response.Problems {
+		log.Printf("Finding: %s, suggestion: %s", problem.Message, problem.Suggestion)
+	}
+}
+
+func newLinter(rules lint.Rules) *linter {
+	return &linter{
+		rules:  rules,
+		reader: os.Stdin,
+		writer: os.Stdout,
+	}
+}
+
+func readLintRequest(r io.Reader) lint.Request {
+	in, err := ioutil.ReadAll(r)
+	if err != nil {
+		log.Fatalf("Error when reading CodeGeneratorRequest: %v", err)
+	}
+
+	var codeGenRequest pluginpb.CodeGeneratorRequest
+	if err := proto.Unmarshal(in, &codeGenRequest); err != nil {
+		log.Fatalf("Error when unmarshaling CodeGeneratorRequest: %v", err)
+	}
+
+	if len(codeGenRequest.GetProtoFile()) == 0 {
+		log.Fatalf("Error: zero proto files in CodeGeneratorRequest")
+	}
+
+	fd := codeGenRequest.GetProtoFile()[0]
+	f, err := protodesc.NewFile(fd, protoregistry.NewFiles())
+	if err != nil {
+		log.Fatalf("Error when converting proto to descriptor: %v", err)
+	}
+
+	ctx := context.Background()
+	source, err := lint.NewDescriptorSource(fd)
+	if err != nil {
+		return lintRequest{
+			protoFile: f,
+			context:   lint.NewContext(ctx),
+		}
+	}
+
+	return lintRequest{
+		protoFile: f,
+		context:   lint.NewContextWithDescriptorSource(ctx, source),
+	}
+}
+
+type lintRequest struct {
+	protoFile protoreflect.FileDescriptor
+	context   lint.Context
+}
+
+func (r lintRequest) ProtoFile() protoreflect.FileDescriptor {
+	return r.protoFile
+}
+
+func (r lintRequest) Context() lint.Context {
+	return r.context
+}

go.mod

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+module github.com/jgeewax/api-linter
+
+go 1.12
+
+require (
+	github.com/golang/protobuf/v2 v2.0.0-20190115031900-66c365cf7239
+	github.com/iancoleman/strcase v0.0.0-20180726023541-3605ed457bf7
+	github.com/stretchr/testify v1.3.0
+)

go.sum

@@ -0,0 +1,23 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang/protobuf v1.2.1-0.20181127190454-8d0c54c12466/go.mod h1:Qd/q+1AKNOZr9uGQzbzCmRO6sUih6GTPZv6a1/R87v0=
+github.com/golang/protobuf v1.2.1-0.20181205191652-7e65e513332f h1:jEoef3K+ZQwZ7UB1iGu6KhX8hS9cYw1aXR7djS3Vn10=
+github.com/golang/protobuf v1.2.1-0.20181205191652-7e65e513332f/go.mod h1:asK8yRb/+zxJTE0SbTESCku/4OjiDfbPwk4rEyIatUA=
+github.com/golang/protobuf/v2 v2.0.0-20181127193627-d7e97bc71bcb/go.mod h1:MgUD+N3FwzDmj2CdMsT5ap7K7jx+c9cQDQ7fVhmH+Xw=
+github.com/golang/protobuf/v2 v2.0.0-20190115031900-66c365cf7239 h1:gRJbl/8g6n9YmDWRAI93uRuIVnw/ESX2o/SMfLO3QOY=
+github.com/golang/protobuf/v2 v2.0.0-20190115031900-66c365cf7239/go.mod h1:sjQt90Yu/7/I4QgfZq+CzFOly7327WbVZ1EDQjIlnMI=
+github.com/google/go-cmp v0.2.1-0.20181101181452-745b8ec83783/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
+github.com/iancoleman/strcase v0.0.0-20180726023541-3605ed457bf7 h1:ux/56T2xqZO/3cP1I2F86qpeoYPCOzk+KF/UH/Ar+lk=
+github.com/iancoleman/strcase v0.0.0-20180726023541-3605ed457bf7/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20180926154720-4dfa2610cdf3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/tools v0.0.0-20180904205237-0aa4b8830f48/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20180928181343-b3c0be4c978b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+google.golang.org/genproto v0.0.0-20180831171423-11092d34479b/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=

lint/context.go

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+package lint
+
+import "context"
+
+// Context provides additional information for a rule to perform linting.
+type Context struct {
+	context    context.Context
+	descSource DescriptorSource
+}
+
+// NewContext creates a new `Context`.
+func NewContext(ctx context.Context) Context {
+	return Context{
+		context: ctx,
+	}
+}
+
+// NewContextWithDescriptorSource creates a new `Context` with the source.
+func NewContextWithDescriptorSource(ctx context.Context, source DescriptorSource) Context {
+	return Context{
+		context:    ctx,
+		descSource: source,
+	}
+}
+
+// DescriptorSource returns a `DescriptorSource` if available; otherwise,
+// returns (nil, ErrSourceInfoNotAvailable).
+//
+// The returned `DescriptorSource` contains additional information
+// about a protobuf descriptor, such as comments and location lookups.
+func (c Context) DescriptorSource() DescriptorSource {
+	return c.descSource
+}

lint/lint.go

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+// Package lint contains interfaces and functions to check API styles in
+// Google Protobuf APIs.
+package lint

lint/location.go

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+package lint
+
+// Location describes a location in a source code file.
+type Location struct {
+	Start, End Position
+}
+
+// IsValid checks if the location struct is constructed properly and
+// returns true if it's valid.
+func (l Location) IsValid() bool {
+	return l.Start.IsValid() && l.End.IsValid()
+}
+
+// Position describes a one-based position in a source code file.
+type Position struct {
+	Line, Column int
+}
+
+// IsValid checks if the position struct is constructed properly and
+// returns true if it's valid.
+func (p Position) IsValid() bool {
+	return p.Line > 0 && p.Column > 0
+}
+
+// StartLocation marks the very start position in a file.
+var StartLocation = Location{
+	Start: Position{1, 1},
+	End:   Position{1, 1},
+}

lint/problem.go

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+package lint
+
+import (
+	"github.com/golang/protobuf/v2/reflect/protoreflect"
+)
+
+// Problem contains information about a result produced by an API Linter.
+type Problem struct {
+	// Message provides a short description of the problem.
+	Message string
+	// Suggestion provides a suggested fix, if applicable.
+	Suggestion string
+	// Location provides the location of the problem. If both
+	// `Location` and `Descriptor` are specified, the location
+	// is then used from `Location` instead of `Descriptor`.
+	Location Location
+	// Descriptor provides the descriptor related
+	// to the problem. If present and `Location` is not
+	// specified, then the starting location of the descriptor
+	// is used as the location of the problem.
+	Descriptor protoreflect.Descriptor
+}

lint/request.go

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+package lint
+
+import "github.com/golang/protobuf/v2/reflect/protoreflect"
+
+// Request defines input data for a rule to perform linting.
+type Request interface {
+	// ProtoFile returns a `FileDescriptor` when the rule's `FileTypes`
+	// contains `ProtoFile`.
+	ProtoFile() protoreflect.FileDescriptor
+	Context() Context
+}

lint/response.go

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+package lint
+
+// Response describes the result returned by a rule.
+type Response struct {
+	Problems []Problem
+}
+
+// mrge merges another response.
+func (resp *Response) merge(other Response) {
+	resp.Problems = append(resp.Problems, other.Problems...)
+}