add auth

and some other improvements

cmd/go-project-template/main.go

@@ -9,7 +9,7 @@ import (
 
 	"git.janky.solutions/finn/go-project-template/config"
 	"git.janky.solutions/finn/go-project-template/db"
-	"git.janky.solutions/finn/go-project-template/httpserver"
+	"git.janky.solutions/finn/go-project-template/web"
 )
 
 func main() {
@@ -17,10 +17,9 @@ func main() {
 }
 
 func run() {
-	if err := config.Load(); err != nil {
+	if err := config.Load(context.Background()); err != nil {
 		logrus.WithError(err).Fatal("error loading config")
 	}
-	logrus.SetLevel(logrus.DebugLevel)
 
 	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
 	defer cancel()
@@ -29,11 +28,11 @@ func run() {
 		logrus.WithError(err).Fatal("error migrating database")
 	}
 
-	go httpserver.ListenAndServe()
+	go web.ListenAndServe()
 
 	<-ctx.Done()
 
-	if err := httpserver.Shutdown(ctx); err != nil {
+	if err := web.Shutdown(ctx); err != nil {
 		logrus.WithError(err).Error("error shutting down web server")
 	}
 }

config/config.go

@@ -1,22 +1,42 @@
 package config
 
 import (
+	"context"
 	"encoding/json"
+	"errors"
+	"fmt"
 	"os"
+	"time"
 
 	"github.com/sirupsen/logrus"
+	"golang.org/x/exp/rand"
 )
 
+func init() {
+	rand.Seed(uint64(time.Now().UnixNano()))
+}
+
 type Config struct {
 	Database string
-	HTTPBind string
+	Web      WebConfig
+	OAuth2   OAuth2
+	LogLevel string
+}
+
+type WebConfig struct {
+	Bind       string
+	SessionKey string
+	BaseURL    string
 }
 
 var C = Config{
-	HTTPBind: ":8080",
+	LogLevel: "INFO",
+	Web: WebConfig{
+		Bind: ":8080",
+	},
 }
 
-func Load() error {
+func Load(ctx context.Context) error {
 	logrus.Info("loading config file")
 
 	f, err := os.Open("go-project-template.json")
@@ -30,5 +50,29 @@ func Load() error {
 		return err
 	}
 
+	level, err := logrus.ParseLevel(C.LogLevel)
+	if err != nil {
+		return fmt.Errorf("error parsing requested log level %s: %v", C.LogLevel, err)
+	}
+	logrus.SetLevel(level)
+
+	if C.Web.SessionKey == "" {
+		logrus.Info("No session key specified. Here's a good one if you need it: ", generateSessionKey())
+		return errors.New("session key may not be empty")
+	}
+
+	if err := C.OAuth2.Load(ctx); err != nil {
+		return err
+	}
 	return nil
 }
+
+var letterRunes = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")
+
+func generateSessionKey() string {
+	b := make([]rune, 64)
+	for i := range b {
+		b[i] = letterRunes[rand.Intn(len(letterRunes))]
+	}
+	return string(b)
+}

config/oauth.go

@@ -0,0 +1,60 @@
+package config
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"time"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+	"golang.org/x/oauth2"
+)
+
+type OAuth2 struct {
+	ClientID     string
+	ClientSecret string
+	ProviderURL  string
+	Scopes       []string
+
+	provider *oidc.Provider
+}
+
+func (o *OAuth2) Load(ctx context.Context) error {
+	ctx, cancel := context.WithTimeout(ctx, time.Second*10)
+	defer cancel()
+
+	provider, err := oidc.NewProvider(ctx, o.ProviderURL)
+	if err != nil {
+		return err
+	}
+
+	hasOpenIDScope := false
+	for _, scope := range o.Scopes {
+		if scope == oidc.ScopeOpenID {
+			hasOpenIDScope = true
+			break
+		}
+	}
+	if !hasOpenIDScope {
+		o.Scopes = append(o.Scopes, oidc.ScopeOpenID)
+	}
+
+	o.provider = provider
+	return nil
+}
+
+func (o OAuth2) GetConfig(postAuthPath string) *oauth2.Config {
+	params := url.Values{}
+	params.Add("dest", postAuthPath)
+	return &oauth2.Config{
+		ClientID:     o.ClientID,
+		ClientSecret: o.ClientSecret,
+		RedirectURL:  fmt.Sprintf("%s/auth/finish", C.Web.BaseURL),
+		Endpoint:     o.provider.Endpoint(),
+		Scopes:       append([]string{oidc.ScopeOpenID}, o.Scopes...),
+	}
+}
+
+func (o OAuth2) UserInfo(ctx context.Context, tokenSource oauth2.TokenSource) (*oidc.UserInfo, error) {
+	return o.provider.UserInfo(ctx, tokenSource)
+}

db/example.sql.go

@@ -1,63 +0,0 @@
-// Code generated by sqlc. DO NOT EDIT.
-// versions:
-//   sqlc v1.20.0
-// source: example.sql
-
-package db
-
-import (
-	"context"
-)
-
-const exampleCreate = `-- name: ExampleCreate :exec
-INSERT INTO example (name) VALUES ($1)
-`
-
-func (q *Queries) ExampleCreate(ctx context.Context, name string) error {
-	_, err := q.db.Exec(ctx, exampleCreate, name)
-	return err
-}
-
-const exampleDelete = `-- name: ExampleDelete :exec
-DELETE FROM example WHERE id = $1
-`
-
-func (q *Queries) ExampleDelete(ctx context.Context, id int64) error {
-	_, err := q.db.Exec(ctx, exampleDelete, id)
-	return err
-}
-
-const exampleGetAll = `-- name: ExampleGetAll :many
-SELECT id, name FROM example
-`
-
-func (q *Queries) ExampleGetAll(ctx context.Context) ([]Example, error) {
-	rows, err := q.db.Query(ctx, exampleGetAll)
-	if err != nil {
-		return nil, err
-	}
-	defer rows.Close()
-	var items []Example
-	for rows.Next() {
-		var i Example
-		if err := rows.Scan(&i.ID, &i.Name); err != nil {
-			return nil, err
-		}
-		items = append(items, i)
-	}
-	if err := rows.Err(); err != nil {
-		return nil, err
-	}
-	return items, nil
-}
-
-const exampleGetByID = `-- name: ExampleGetByID :one
-SELECT id, name FROM example WHERE id = $1
-`
-
-func (q *Queries) ExampleGetByID(ctx context.Context, id int64) (Example, error) {
-	row := q.db.QueryRow(ctx, exampleGetByID, id)
-	var i Example
-	err := row.Scan(&i.ID, &i.Name)
-	return i, err
-}

db/migrations/001_init.sql

@@ -1,12 +1,13 @@
 -- +goose Up
 -- +goose StatementBegin
-CREATE TABLE example (
+CREATE TABLE users (
-    id BIGSERIAL PRIMARY KEY,
+    id SERIAL PRIMARY KEY,
-    name TEXT NOT NULL
+    idp_sub VARCHAR(36) UNIQUE NOT NULL, -- is this long enough for other IDPs? Keycloak gives a UUID
-)
+    username VARCHAR(50) NOT NULL
+);
 -- +goose StatementEnd
 
 -- +goose Down
 -- +goose StatementBegin
-DROP TABLE example;
+DROP TABLE users;
 -- +goose StatementEnd

db/models.go

@@ -6,7 +6,8 @@ package db
 
 import ()
 
-type Example struct {
+type User struct {
-	ID   int64
+	ID       int32
-	Name string
+	IdpSub   string
+	Username string
 }

db/queries/example.sql

@@ -1,11 +0,0 @@
--- name: ExampleCreate :exec
-INSERT INTO example (name) VALUES ($1);
-
--- name: ExampleGetByID :one
-SELECT * FROM example WHERE id = $1;
-
--- name: ExampleGetAll :many
-SELECT * FROM example;
-
--- name: ExampleDelete :exec
-DELETE FROM example WHERE id = $1;

db/queries/users.sql

@@ -0,0 +1,8 @@
+-- name: GetUser :one
+SELECT * FROM users WHERE id = $1 LIMIT 1;
+
+-- name: GetUserByIDP :one
+SELECT * FROM users WHERE idp_sub = $1 LIMIT 1;
+
+-- name: CreateUser :one
+INSERT INTO users (username, idp_sub) VALUES ($1, $2) RETURNING *;

db/users.sql.go

@@ -0,0 +1,48 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.20.0
+// source: users.sql
+
+package db
+
+import (
+	"context"
+)
+
+const createUser = `-- name: CreateUser :one
+INSERT INTO users (username, idp_sub) VALUES ($1, $2) RETURNING id, idp_sub, username
+`
+
+type CreateUserParams struct {
+	Username string
+	IdpSub   string
+}
+
+func (q *Queries) CreateUser(ctx context.Context, arg CreateUserParams) (User, error) {
+	row := q.db.QueryRow(ctx, createUser, arg.Username, arg.IdpSub)
+	var i User
+	err := row.Scan(&i.ID, &i.IdpSub, &i.Username)
+	return i, err
+}
+
+const getUser = `-- name: GetUser :one
+SELECT id, idp_sub, username FROM users WHERE id = $1 LIMIT 1
+`
+
+func (q *Queries) GetUser(ctx context.Context, id int32) (User, error) {
+	row := q.db.QueryRow(ctx, getUser, id)
+	var i User
+	err := row.Scan(&i.ID, &i.IdpSub, &i.Username)
+	return i, err
+}
+
+const getUserByIDP = `-- name: GetUserByIDP :one
+SELECT id, idp_sub, username FROM users WHERE idp_sub = $1 LIMIT 1
+`
+
+func (q *Queries) GetUserByIDP(ctx context.Context, idpSub string) (User, error) {
+	row := q.db.QueryRow(ctx, getUserByIDP, idpSub)
+	var i User
+	err := row.Scan(&i.ID, &i.IdpSub, &i.Username)
+	return i, err
+}

go-project-template.sample.json

@@ -1,3 +1,13 @@
 {
-    "database": "postgresql://postgres:password@localhost:5432/postgres"
+    "loglevel": "debug",
+    "database": "postgresql://postgres:password@localhost:5432/postgres",
+    "web": {
+        "baseurl": "http://localhost:8080",
+        "sessionKey": ""
+    },
+    "oauth2": {
+        "ClientID": "",
+        "ClientSecret": "",
+        "ProviderURL": "https://my.keycloak.instance/realms/example"
+    }
 }

go.mod

@@ -3,13 +3,20 @@ module git.janky.solutions/finn/go-project-template
 go 1.21.8
 
 require (
+	github.com/coreos/go-oidc/v3 v3.11.0
+	github.com/google/uuid v1.6.0
+	github.com/gorilla/sessions v1.3.0
 	github.com/jackc/pgx/v5 v5.5.5
 	github.com/labstack/echo/v4 v4.12.0
 	github.com/pressly/goose/v3 v3.20.0
 	github.com/sirupsen/logrus v1.9.3
+	golang.org/x/exp v0.0.0-20240325151524-a685a6edb6d8
+	golang.org/x/oauth2 v0.21.0
 )
 
 require (
+	github.com/go-jose/go-jose/v4 v4.0.2 // indirect
+	github.com/gorilla/securecookie v1.1.2 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
 	github.com/jackc/puddle/v2 v2.2.1 // indirect
@@ -21,9 +28,9 @@ require (
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasttemplate v1.2.2 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
-	golang.org/x/crypto v0.22.0 // indirect
+	golang.org/x/crypto v0.25.0 // indirect
-	golang.org/x/net v0.24.0 // indirect
+	golang.org/x/net v0.27.0 // indirect
 	golang.org/x/sync v0.7.0 // indirect
-	golang.org/x/sys v0.19.0 // indirect
+	golang.org/x/sys v0.22.0 // indirect
-	golang.org/x/text v0.14.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
 )

go.sum

@@ -1,10 +1,22 @@
+github.com/coreos/go-oidc/v3 v3.11.0 h1:Ia3MxdwpSw702YW0xgfmP1GVCMA9aEFWu12XUZ3/OtI=
+github.com/coreos/go-oidc/v3 v3.11.0/go.mod h1:gE3LgjOgFoHi9a4ce4/tJczr0Ai2/BoDhf0r5lltWI0=
 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/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
+github.com/go-jose/go-jose/v4 v4.0.2 h1:R3l3kkBds16bO7ZFAEEcofK0MkrAJt3jlJznWZG0nvk=
+github.com/go-jose/go-jose/v4 v4.0.2/go.mod h1:WVf9LFMHh/QVrmqrOfqun0C45tMe3RoiKJMPvgWwLfY=
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/gofuzz v1.2.0 h1:xRy4A+RhZaiKjJ1bPfwQ8sedCA+YS2YcCHW6ec7JMi0=
+github.com/google/gofuzz v1.2.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/securecookie v1.1.2 h1:YCIWL56dvtr73r6715mJs5ZvhtnY73hBvEF8kXD8ePA=
+github.com/gorilla/securecookie v1.1.2/go.mod h1:NfCASbcHqRSY+3a8tlWJwsQap2VX5pwzwo4h3eOamfo=
+github.com/gorilla/sessions v1.3.0 h1:XYlkq7KcpOB2ZhHBPv5WpjMIxrQosiZanfoy1HLZFzg=
+github.com/gorilla/sessions v1.3.0/go.mod h1:ePLdVu+jbEgHH+KWw8I1z2wqd0BAdAQh/8LRvBeoNcQ=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
@@ -49,19 +61,23 @@ github.com/valyala/fasttemplate v1.2.2 h1:lxLXG0uE3Qnshl9QyaK6XJxMXlQZELvChBOCmQ
 github.com/valyala/fasttemplate v1.2.2/go.mod h1:KHLXt3tVN2HBp8eijSv/kGJopbvo7S+qRAEEKiv+SiQ=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
 go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
-golang.org/x/crypto v0.22.0 h1:g1v0xeRhjcugydODzvb3mEM9SQ0HGp9s/nh3COQ/C30=
+golang.org/x/crypto v0.25.0 h1:ypSNr+bnYL2YhwoMt2zPxHFmbAN1KZs/njMG3hxUp30=
-golang.org/x/crypto v0.22.0/go.mod h1:vr6Su+7cTlO45qkww3VDJlzDn0ctJvRgYbC2NvXHt+M=
+golang.org/x/crypto v0.25.0/go.mod h1:T+wALwcMOSE0kXgUAnPAHqTLW+XHgcELELW8VaDgm/M=
-golang.org/x/net v0.24.0 h1:1PcaxkF854Fu3+lvBIx5SYn9wRlBzzcnHZSiaFFAb0w=
+golang.org/x/exp v0.0.0-20240325151524-a685a6edb6d8 h1:aAcj0Da7eBAtrTp03QXWvm88pSyOt+UgdZw2BFZ+lEw=
-golang.org/x/net v0.24.0/go.mod h1:2Q7sJY5mzlzWjKtYUEXSlBWCdyaioyXzRB2RtU8KVE8=
+golang.org/x/exp v0.0.0-20240325151524-a685a6edb6d8/go.mod h1:CQ1k9gNrJ50XIzaKCRR2hssIjF07kZFEiieALBM/ARQ=
+golang.org/x/net v0.27.0 h1:5K3Njcw06/l2y9vpGCSdcxWOYHOUk3dVNGDXN+FvAys=
+golang.org/x/net v0.27.0/go.mod h1:dDi0PyhWNoiUOrAS8uXv/vnScO4wnHQO4mj9fn/RytE=
+golang.org/x/oauth2 v0.21.0 h1:tsimM75w1tF/uws5rbeHzIWxEqElMehnc+iW793zsZs=
+golang.org/x/oauth2 v0.21.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
 golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.19.0 h1:q5f1RH2jigJ1MoAWp2KTp3gm5zAGFUTarQZ5U386+4o=
+golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
-golang.org/x/sys v0.19.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
-golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 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=

web/auth.go

@@ -0,0 +1,142 @@
+package web
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/google/uuid"
+	"github.com/gorilla/sessions"
+	pgx "github.com/jackc/pgx/v5"
+	echo "github.com/labstack/echo/v4"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/oauth2"
+
+	"git.janky.solutions/finn/go-project-template/config"
+	"git.janky.solutions/finn/go-project-template/db"
+)
+
+const (
+	sessionName           = "session"
+	contextKeySession     = "session"
+	contextKeyUserID      = "user_id"
+	sessionValueAuthState = "auth_state"
+	sessionValueAuthUser  = "auth_user"
+	queryParamState       = "state"
+	queryParamCode        = "code"
+)
+
+var sessionStore *sessions.CookieStore
+
+func authBegin(c echo.Context) error {
+	session := c.Get(contextKeySession).(*sessions.Session)
+
+	state, ok := session.Values[sessionValueAuthState]
+	if !ok {
+		state = uuid.New().String()
+		session.Values[sessionValueAuthState] = state
+		if err := session.Save(c.Request(), c.Response()); err != nil {
+			return fmt.Errorf("error saving session: %v", err)
+		}
+	}
+
+	postAuthPath := c.QueryParam("dest")
+	if postAuthPath == "" {
+		logrus.WithField("params", c.Request().URL.RawQuery).Debug("no post-auth path")
+		postAuthPath = "/"
+	}
+
+	return c.Redirect(http.StatusFound, config.C.OAuth2.GetConfig(postAuthPath).AuthCodeURL(state.(string)))
+}
+
+func authFinish(c echo.Context) error {
+	session := c.Get(contextKeySession).(*sessions.Session)
+
+	postAuthPath := c.QueryParam("dest")
+	if postAuthPath == "" {
+		postAuthPath = "/"
+	}
+
+	if c.QueryParam(queryParamState) != session.Values[sessionValueAuthState] {
+		logrus.WithFields(logrus.Fields{
+			"provided_state": c.QueryParam(queryParamState),
+			"expected_state": session.Values[sessionValueAuthState],
+		}).Debug("unexpected auth state value, restarting auth process")
+
+		query := url.Values{}
+		query.Set("dest", postAuthPath)
+		return c.Redirect(http.StatusFound, fmt.Sprintf("/auth/login?%s", query.Encode()))
+	}
+
+	ctx := c.Request().Context()
+
+	token, err := config.C.OAuth2.GetConfig(postAuthPath).Exchange(ctx, c.QueryParam(queryParamCode))
+	if err != nil {
+		return err
+	}
+
+	userInfo, err := config.C.OAuth2.UserInfo(ctx, oauth2.StaticTokenSource(token))
+	if err != nil {
+		return err
+	}
+
+	var claims map[string]interface{}
+	if err := userInfo.Claims(&claims); err != nil {
+		return err
+	}
+
+	queries, dbc, err := db.Get(ctx)
+	if err != nil {
+		return err
+	}
+	defer dbc.Close(ctx)
+
+	user, err := queries.GetUserByIDP(ctx, userInfo.Subject)
+	if err != nil {
+		if !errors.Is(err, pgx.ErrNoRows) {
+			return fmt.Errorf("error finding user by subject (sub=%s): %+v", userInfo.Subject, err)
+		}
+
+		user, err = queries.CreateUser(ctx, db.CreateUserParams{
+			Username: claims["preferred_username"].(string),
+			IdpSub:   userInfo.Subject,
+		})
+		if err != nil {
+			return fmt.Errorf("error adding new user to db: %v", err)
+		}
+	}
+
+	session.Values[sessionValueAuthUser] = user.ID
+	if err := session.Save(c.Request(), c.Response()); err != nil {
+		return fmt.Errorf("error saving session: %v", err)
+	}
+
+	dest := c.QueryParam("dest")
+	if dest == "" {
+		dest = "/"
+	}
+
+	return c.Redirect(http.StatusFound, dest)
+}
+
+func authMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		if strings.HasPrefix(c.Request().URL.Path, "/auth") {
+			return next(c)
+		}
+
+		session := c.Get(contextKeySession).(*sessions.Session)
+		user, ok := session.Values[sessionValueAuthUser]
+		if !ok {
+			query := url.Values{}
+			query.Set("dest", c.Request().URL.Path)
+			return c.Redirect(http.StatusFound, fmt.Sprintf("/auth/begin?%s", query.Encode()))
+		}
+
+		c.Set(contextKeyUserID, user)
+
+		return next(c)
+	}
+}

web/index.go

@@ -1,4 +1,4 @@
-package httpserver
+package web
 
 import (
 	"net/http"

web/server.go

@@ -1,4 +1,4 @@
-package httpserver
+package web
 
 import (
 	"context"
@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/gorilla/sessions"
 	echo "github.com/labstack/echo/v4"
 	"github.com/sirupsen/logrus"
 
@@ -16,20 +17,25 @@ import (
 var server *echo.Echo
 
 func ListenAndServe() {
+	sessionStore = sessions.NewCookieStore([]byte(config.C.Web.SessionKey))
+
 	server = echo.New()
 	server.HideBanner = true
 	server.HidePort = true
 	server.HTTPErrorHandler = handleError
 	server.Renderer = &Template{}
-	server.Use(accessLogMiddleware)
+	server.Use(accessLogMiddleware, sessionMiddleware)
 	server.RouteNotFound("/*", notFoundHandler)
 
-	server.GET("/", index)
+	server.GET("/auth/begin", authBegin)
+	server.GET("/auth/finish", authFinish)
+
+	server.GET("/", index, authMiddleware)
 
 	server.StaticFS("/static", Static)
 
-	logrus.WithField("address", config.C.HTTPBind).Info("starting http server")
+	logrus.WithField("address", config.C.Web.Bind).Info("starting http server")
-	err := server.Start(config.C.HTTPBind)
+	err := server.Start(config.C.Web.Bind)
 	if err != http.ErrServerClosed {
 		logrus.WithError(err).Fatal("error starting http server")
 	}
@@ -85,3 +91,15 @@ func handleError(err error, c echo.Context) {
 func notFoundHandler(c echo.Context) error {
 	return c.Render(http.StatusNotFound, "404.html", nil)
 }
+
+func sessionMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		session, err := sessionStore.Get(c.Request(), sessionName)
+		if err != nil {
+			return err
+		}
+
+		c.Set(contextKeySession, session)
+		return next(c)
+	}
+}

web/templates.go

@@ -1,4 +1,4 @@
-package httpserver
+package web
 
 import (
 	"embed"