Initial commit

2023-04-20 17:54:42 +00:00
parent 57736da893
commit cb9d3aef62
10 changed files with 565 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,2 @@
+cover.out
+cover.html
--- a/.golangci.yaml
+++ b/.golangci.yaml
@@ -0,0 +1,38 @@
+linters:
+  enable-all: true
+  disable:
+    # re-enable when working
+    - rowserrcheck
+    - wastedassign
+    # maybe enable these
+    - wrapcheck
+    # leave these disabled
+    - cyclop
+    - deadcode
+    - dupl
+    - exhaustivestruct
+    - exhaustruct
+    - forbidigo
+    - forcetypeassert
+    - funlen
+    - gochecknoglobals
+    - gocognit
+    - goconst
+    - godox
+    - golint
+    - gomnd
+    - ifshort
+    - interfacer
+    - lll
+    - maintidx
+    - maligned
+    - nilnil
+    - nestif
+    - nlreturn
+    - nolintlint
+    - nosnakecase
+    - scopelint
+    - structcheck
+    - thelper
+    - varcheck
+    - varnamelen
--- a/bodyintercept.go
+++ b/bodyintercept.go
@@ -0,0 +1,30 @@
+package potency
+
+import (
+	"crypto/sha256"
+	"hash"
+	"io"
+)
+
+type bodyIntercept struct {
+	source io.ReadCloser
+	sha256 hash.Hash
+}
+
+func newBodyIntercept(source io.ReadCloser) *bodyIntercept {
+	return &bodyIntercept{
+		source: source,
+		sha256: sha256.New(),
+	}
+}
+
+func (bi *bodyIntercept) Read(p []byte) (int, error) {
+	numBytes, err := bi.source.Read(p)
+	bi.sha256.Write(p[:numBytes])
+
+	return numBytes, err
+}
+
+func (bi *bodyIntercept) Close() error {
+	return bi.source.Close()
+}
--- a/go.mod
+++ b/go.mod
@@ -0,0 +1,20 @@
+module github.com/gopatchy/potency
+
+go 1.19
+
+require (
+	github.com/dchest/uniuri v1.2.0
+	github.com/go-resty/resty/v2 v2.7.0
+	github.com/gopatchy/jsrest v0.0.0-20230420161234-12a6d6da8b7f
+	github.com/stretchr/testify v1.8.2
+	go.uber.org/goleak v1.2.1
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/gopatchy/metadata v0.0.0-20230420053349-25837551c11d // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/vfaronov/httpheader v0.1.0 // indirect
+	golang.org/x/net v0.9.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
--- a/go.sum
+++ b/go.sum
@@ -0,0 +1,40 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dchest/uniuri v1.2.0 h1:koIcOUdrTIivZgSLhHQvKgqdWZq5d7KdMEWF1Ud6+5g=
+github.com/dchest/uniuri v1.2.0/go.mod h1:fSzm4SLHzNZvWLvWJew423PhAzkpNQYq+uNLq4kxhkY=
+github.com/go-resty/resty/v2 v2.7.0 h1:me+K9p3uhSmXtrBZ4k9jcEAfJmuC8IivWHwaLZwPrFY=
+github.com/go-resty/resty/v2 v2.7.0/go.mod h1:9PWDzw47qPphMRFfhsyk0NnSgvluHcljSMVIq3w7q0I=
+github.com/gopatchy/jsrest v0.0.0-20230420161234-12a6d6da8b7f h1:1uGPJm9K0Fro1UEcZpuK6FNPU/U1XX3aS3x0/PdFS40=
+github.com/gopatchy/jsrest v0.0.0-20230420161234-12a6d6da8b7f/go.mod h1:Ryi8LRBLFDhQsMQHuh+6VL7HcFWjBXOEiOy9Ip/Q+Ps=
+github.com/gopatchy/metadata v0.0.0-20230420053349-25837551c11d h1:chunoM47vkWSanIvLx4uRSkLMG6chDZOy09L2tt/bv8=
+github.com/gopatchy/metadata v0.0.0-20230420053349-25837551c11d/go.mod h1:VgD33raUShjDePCDBo55aj+eSXFtUEpMzs+Ie39g2zo=
+github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+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/rogpeppe/go-internal v1.8.1-0.20211023094830-115ce09fd6b4 h1:Ha8xCaq6ln1a+R91Km45Oq6lPXj2Mla6CRJYcuV2h1w=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/vfaronov/httpheader v0.1.0 h1:VdzetvOKRoQVHjSrXcIOwCV6JG5BCAW9rjbVbFPBmb0=
+github.com/vfaronov/httpheader v0.1.0/go.mod h1:ZBxgbYu6nbN5V9Ptd1yYUUan0voD0O8nZLXHyxLgoLE=
+go.uber.org/goleak v1.2.1 h1:NBol2c7O1ZokfZ0LEU9K6Whx/KnwvepVetCUhtKja4A=
+go.uber.org/goleak v1.2.1/go.mod h1:qlT2yGI9QafXHhZZLxlSuNsMw3FFLxBr+tBRlmO1xH4=
+golang.org/x/net v0.0.0-20211029224645-99673261e6eb/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.9.0 h1:aWJ/m6xSmxWBx+V0XRHTlrYrPG56jKsLdTFmsSsCzOM=
+golang.org/x/net v0.9.0/go.mod h1:d48xBJpPfHeWQsugry2m+kC02ZBRGRgulfHnEXEuWns=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
--- a/18
+++ b/18
@@ -0,0 +1,18 @@
+go := env_var_or_default('GOCMD', 'go')
+
+default: tidy test
+
+tidy:
+	{{go}} mod tidy
+	goimports -l -w .
+	gofumpt -l -w .
+	{{go}} fmt ./...
+
+test:
+	{{go}} vet ./...
+	golangci-lint run ./...
+	{{go}} test -race -coverprofile=cover.out -timeout=60s -parallel=10 ./...
+	{{go}} tool cover -html=cover.out -o=cover.html
+
+todo:
+	-git grep -e TODO --and --not -e ignoretodo
--- a/pkg_test.go
+++ b/pkg_test.go
@@ -0,0 +1,11 @@
+package potency_test
+
+import (
+	"testing"
+
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}
--- a/potency.go
+++ b/potency.go
@@ -0,0 +1,189 @@
+package potency
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"sync"
+
+	"github.com/gopatchy/jsrest"
+)
+
+type Potency struct {
+	handler http.Handler
+
+	// TODO: Expire based on time; probably use age-based linked list and delete at write time
+	cache   map[string]*savedResult
+	cacheMu sync.RWMutex
+
+	inProgress   map[string]bool
+	inProgressMu sync.Mutex
+}
+
+type savedResult struct {
+	Method        string      `json:"method"`
+	URL           string      `json:"url"`
+	RequestHeader http.Header `json:"requestHeader"`
+	Sha256        string      `json:"sha256"`
+
+	StatusCode     int         `json:"statusCode"`
+	ResponseHeader http.Header `json:"responseHeader"`
+	ResponseBody   []byte      `json:"responseBody"`
+}
+
+var (
+	ErrConflict       = errors.New("conflict")
+	ErrMismatch       = errors.New("idempotency mismatch")
+	ErrBodyMismatch   = fmt.Errorf("request body mismatch: %w", ErrMismatch)
+	ErrMethodMismatch = fmt.Errorf("HTTP method mismatch: %w", ErrMismatch)
+	ErrURLMismatch    = fmt.Errorf("URL mismatch: %w", ErrMismatch)
+	ErrHeaderMismatch = fmt.Errorf("Header mismatch: %w", ErrMismatch)
+	ErrInvalidKey     = errors.New("invalid Idempotency-Key")
+
+	criticalHeaders = []string{
+		"Accept",
+		"Authorization",
+	}
+)
+
+func NewPotency(handler http.Handler) *Potency {
+	return &Potency{
+		handler:    handler,
+		cache:      map[string]*savedResult{},
+		inProgress: map[string]bool{},
+	}
+}
+
+func (p *Potency) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	val := r.Header.Get("Idempotency-Key")
+	if val == "" {
+		p.handler.ServeHTTP(w, r)
+		return
+	}
+
+	err := p.serveHTTP(w, r, val)
+	if err != nil {
+		jsrest.WriteError(w, err)
+	}
+}
+
+func (p *Potency) serveHTTP(w http.ResponseWriter, r *http.Request, val string) error {
+	if len(val) < 2 || !strings.HasPrefix(val, `"`) || !strings.HasSuffix(val, `"`) {
+		return jsrest.Errorf(jsrest.ErrBadRequest, "%s (%w)", val, ErrInvalidKey)
+	}
+
+	key := val[1 : len(val)-1]
+
+	saved := p.read(key)
+
+	if saved != nil {
+		if r.Method != saved.Method {
+			return jsrest.Errorf(jsrest.ErrBadRequest, "%s (%w)", r.Method, ErrMethodMismatch)
+		}
+
+		if r.URL.String() != saved.URL {
+			return jsrest.Errorf(jsrest.ErrBadRequest, "%s (%w)", r.URL.String(), ErrURLMismatch)
+		}
+
+		for _, h := range criticalHeaders {
+			if saved.RequestHeader.Get(h) != r.Header.Get(h) {
+				return jsrest.Errorf(jsrest.ErrBadRequest, "%s: %s (%w)", h, r.Header.Get(h), ErrHeaderMismatch)
+			}
+		}
+
+		h := sha256.New()
+
+		_, err := io.Copy(h, r.Body)
+		if err != nil {
+			return jsrest.Errorf(jsrest.ErrBadRequest, "hash request body failed (%w)", err)
+		}
+
+		hexed := hex.EncodeToString(h.Sum(nil))
+		if hexed != saved.Sha256 {
+			return jsrest.Errorf(jsrest.ErrBadRequest, "%s vs %s (%w)", hexed, saved.Sha256, ErrBodyMismatch)
+		}
+
+		for key, vals := range saved.ResponseHeader {
+			w.Header().Set(key, vals[0])
+		}
+
+		w.WriteHeader(saved.StatusCode)
+		_, _ = w.Write(saved.ResponseBody)
+
+		return nil
+	}
+
+	// Store miss, proceed to normal execution with interception
+	err := p.lockKey(key)
+	if err != nil {
+		return jsrest.Errorf(jsrest.ErrConflict, "%s", key)
+	}
+
+	defer p.unlockKey(key)
+
+	requestHeader := http.Header{}
+	for _, h := range criticalHeaders {
+		requestHeader.Set(h, r.Header.Get(h))
+	}
+
+	bi := newBodyIntercept(r.Body)
+	r.Body = bi
+
+	rwi := newResponseWriterIntercept(w)
+	w = rwi
+
+	p.handler.ServeHTTP(w, r)
+
+	save := &savedResult{
+		Method:        r.Method,
+		URL:           r.URL.String(),
+		RequestHeader: requestHeader,
+		Sha256:        hex.EncodeToString(bi.sha256.Sum(nil)),
+
+		StatusCode:     rwi.statusCode,
+		ResponseHeader: rwi.Header(),
+		ResponseBody:   rwi.buf.Bytes(),
+	}
+
+	p.write(key, save)
+
+	return nil
+}
+
+func (p *Potency) lockKey(key string) error {
+	p.inProgressMu.Lock()
+	defer p.inProgressMu.Unlock()
+
+	if p.inProgress[key] {
+		return ErrConflict
+	}
+
+	p.inProgress[key] = true
+
+	return nil
+}
+
+func (p *Potency) unlockKey(key string) {
+	p.inProgressMu.Lock()
+	defer p.inProgressMu.Unlock()
+
+	delete(p.inProgress, key)
+}
+
+func (p *Potency) read(key string) *savedResult {
+	p.cacheMu.RLock()
+	defer p.cacheMu.RUnlock()
+
+	return p.cache[key]
+}
+
+func (p *Potency) write(key string, sr *savedResult) {
+	p.cacheMu.Lock()
+	defer p.cacheMu.Unlock()
+
+	p.cache[key] = sr
+}
--- a/potency_test.go
+++ b/potency_test.go
@@ -0,0 +1,183 @@
+package potency_test
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/dchest/uniuri"
+	"github.com/go-resty/resty/v2"
+	"github.com/gopatchy/potency"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGET(t *testing.T) {
+	t.Parallel()
+
+	ts := newTestServer(t)
+	defer ts.shutdown(t)
+
+	key1 := uniuri.New()
+
+	resp, err := ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		Get("")
+	require.NoError(t, err)
+	require.False(t, resp.IsError())
+	require.Equal(t, "bar", resp.Header().Get("X-Response"))
+
+	resp1 := resp.String()
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		Get("")
+	require.NoError(t, err)
+	require.False(t, resp.IsError())
+	require.Equal(t, "bar", resp.Header().Get("X-Response"))
+	require.Equal(t, resp1, resp.String())
+
+	key2 := uniuri.New()
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key2)).
+		Get("")
+	require.NoError(t, err)
+	require.False(t, resp.IsError())
+	require.Equal(t, "bar", resp.Header().Get("X-Response"))
+
+	resp2 := resp.String()
+
+	require.NotEqual(t, resp2, resp1)
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		Get("x")
+	require.NoError(t, err)
+	require.True(t, resp.IsError())
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		Delete("")
+	require.NoError(t, err)
+	require.True(t, resp.IsError())
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		SetHeader("Authorization", "Bearer xyz").
+		Get("")
+	require.NoError(t, err)
+	require.True(t, resp.IsError())
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		SetHeader("Accept", "text/xml").
+		Get("")
+	require.NoError(t, err)
+	require.True(t, resp.IsError())
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		SetHeader("X-Test", "foo").
+		Get("")
+	require.NoError(t, err)
+	require.False(t, resp.IsError())
+	require.Equal(t, "bar", resp.Header().Get("X-Response"))
+	require.Equal(t, resp1, resp.String())
+}
+
+func TestPOST(t *testing.T) {
+	t.Parallel()
+
+	ts := newTestServer(t)
+	defer ts.shutdown(t)
+
+	key1 := uniuri.New()
+
+	resp, err := ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		SetBody("test1").
+		Post("")
+	require.NoError(t, err)
+	require.False(t, resp.IsError())
+
+	resp1 := resp.String()
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		SetBody("test1").
+		Post("")
+	require.NoError(t, err)
+	require.False(t, resp.IsError())
+	require.Equal(t, resp1, resp.String())
+
+	resp, err = ts.r().
+		SetHeader("Idempotency-Key", fmt.Sprintf(`"%s"`, key1)).
+		SetBody("test2").
+		Post("")
+	require.NoError(t, err)
+	require.True(t, resp.IsError())
+}
+
+type testServer struct {
+	dir string
+	srv *http.Server
+	rst *resty.Client
+}
+
+func newTestServer(t *testing.T) *testServer {
+	dir, err := os.MkdirTemp("", "")
+	require.NoError(t, err)
+
+	mux := http.NewServeMux()
+	p := potency.NewPotency(mux)
+
+	listener, err := net.Listen("tcp", "[::]:0")
+	require.NoError(t, err)
+
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		_, err := io.ReadAll(r.Body)
+		require.NoError(t, err)
+
+		w.Header().Add("X-Response", "bar")
+
+		_, err = w.Write([]byte(uniuri.New()))
+		require.NoError(t, err)
+	})
+
+	srv := &http.Server{
+		Handler:           p,
+		ReadHeaderTimeout: 1 * time.Second,
+	}
+
+	go func() {
+		_ = srv.Serve(listener)
+	}()
+
+	baseURL := fmt.Sprintf("http://[::1]:%d/", listener.Addr().(*net.TCPAddr).Port)
+
+	rst := resty.New().
+		SetHeader("Content-Type", "application/json").
+		SetBaseURL(baseURL)
+
+	return &testServer{
+		dir: dir,
+		srv: srv,
+		rst: rst,
+	}
+}
+
+func (ts *testServer) r() *resty.Request {
+	return ts.rst.R()
+}
+
+func (ts *testServer) shutdown(t *testing.T) {
+	err := ts.srv.Shutdown(context.Background())
+	require.NoError(t, err)
+
+	os.RemoveAll(ts.dir)
+}
--- a/responsewriterintercept.go
+++ b/responsewriterintercept.go
@@ -0,0 +1,34 @@
+package potency
+
+import (
+	"bytes"
+	"net/http"
+)
+
+type responseWriterIntercept struct {
+	dest       http.ResponseWriter
+	buf        bytes.Buffer
+	statusCode int
+}
+
+func newResponseWriterIntercept(dest http.ResponseWriter) *responseWriterIntercept {
+	return &responseWriterIntercept{
+		dest:       dest,
+		buf:        bytes.Buffer{},
+		statusCode: http.StatusOK,
+	}
+}
+
+func (rwi *responseWriterIntercept) Header() http.Header {
+	return rwi.dest.Header()
+}
+
+func (rwi *responseWriterIntercept) Write(data []byte) (int, error) {
+	rwi.buf.Write(data)
+	return rwi.dest.Write(data)
+}
+
+func (rwi *responseWriterIntercept) WriteHeader(statusCode int) {
+	rwi.statusCode = statusCode
+	rwi.dest.WriteHeader(statusCode)
+}