Refactor: Wrap most errors in a custom type

1 files changed, 72 insertions, 41 deletions

diff --git a/internal/oauth.go b/internal/oauth.go
index 98af5a4..c13ea99 100644
--- a/internal/oauth.go
+++ b/internal/oauth.go
@@ -5,7 +5,6 @@ import (
 	"crypto/sha256"
 	"encoding/base64"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"net/http"
 	"net/url"
@@ -20,7 +19,7 @@ import (
 func genState() (string, error) {
 	randomBytes, err := MakeRandomByteSlice(32)
 	if err != nil {
-		return "", &OAuthGenStateUnableError{Err: err}
+		return "", &OAuthGenStateError{Err: err}
 	}
 
 	// For consistency we also use raw url encoding here
@@ -46,7 +45,7 @@ func genChallengeS256(verifier string) string {
 func genVerifier() (string, error) {
 	randomBytes, err := MakeRandomByteSlice(32)
 	if err != nil {
-		return "", &OAuthGenVerifierUnableError{Err: err}
+		return "", &OAuthGenVerifierError{Err: err}
 	}
 
 	return base64.RawURLEncoding.EncodeToString(randomBytes), nil
@@ -95,7 +94,7 @@ func (oauth *OAuth) getTokensWithCallback() error {
 	}
 	mux.HandleFunc("/callback", oauth.Callback)
 	if err := oauth.Session.Server.ListenAndServe(); err != http.ErrServerClosed {
-		return &OAuthFailedCallbackError{Addr: addr, Err: err}
+		return &OAuthCallbackError{Addr: addr, Err: err}
 	}
 	return oauth.Session.CallbackError
 }
@@ -122,7 +121,7 @@ func (oauth *OAuth) getTokensWithAuthCode(authCode string) error {
 	current_time := GenerateTimeSeconds()
 	_, body, bodyErr := HTTPPostWithOpts(reqURL, opts)
 	if bodyErr != nil {
-		return bodyErr
+		return &OAuthAuthError{Err: bodyErr}
 	}
 
 	tokenStructure := OAuthToken{}
@@ -160,7 +159,7 @@ func (oauth *OAuth) getTokensWithRefresh() error {
 	current_time := GenerateTimeSeconds()
 	_, body, bodyErr := HTTPPostWithOpts(reqURL, opts)
 	if bodyErr != nil {
-		return bodyErr
+		return &OAuthRefreshError{Err: bodyErr}
 	}
 
 	tokenStructure := OAuthToken{}
@@ -181,7 +180,7 @@ func (oauth *OAuth) Callback(w http.ResponseWriter, req *http.Request) {
 	// Extract the authorization code
 	code, success := req.URL.Query()["code"]
 	if !success {
-		oauth.Session.CallbackError = &OAuthFailedCallbackParameterError{Parameter: "code", URL: req.URL.String()}
+		oauth.Session.CallbackError = &OAuthCallbackParameterError{Parameter: "code", URL: req.URL.String()}
 		go oauth.Session.Server.Shutdown(oauth.Session.Context)
 		return
 	}
@@ -192,14 +191,14 @@ func (oauth *OAuth) Callback(w http.ResponseWriter, req *http.Request) {
 	// https://datatracker.ietf.org/doc/html/draft-ietf-oauth-v2-1-04#section-7.15
 	state, success := req.URL.Query()["state"]
 	if !success {
-		oauth.Session.CallbackError = &OAuthFailedCallbackParameterError{Parameter: "state", URL: req.URL.String()}
+		oauth.Session.CallbackError = &OAuthCallbackParameterError{Parameter: "state", URL: req.URL.String()}
 		go oauth.Session.Server.Shutdown(oauth.Session.Context)
 		return
 	}
 	// The state is the first entry
 	extractedState := state[0]
 	if extractedState != oauth.Session.State {
-		oauth.Session.CallbackError = &OAuthFailedCallbackStateMatchError{State: extractedState, ExpectedState: oauth.Session.State}
+		oauth.Session.CallbackError = &OAuthCallbackStateMatchError{State: extractedState, ExpectedState: oauth.Session.State}
 		go oauth.Session.Server.Shutdown(oauth.Session.Context)
 		return
 	}
@@ -208,7 +207,7 @@ func (oauth *OAuth) Callback(w http.ResponseWriter, req *http.Request) {
 	// Obtaining the access and refresh tokens
 	err := oauth.getTokensWithAuthCode(extractedCode)
 	if err != nil {
-		oauth.Session.CallbackError = &OAuthFailedCallbackGetTokensError{Err: err}
+		oauth.Session.CallbackError = &OAuthCallbackGetTokensError{Err: err}
 		go oauth.Session.Server.Shutdown(oauth.Session.Context)
 		return
 	}
@@ -225,18 +224,18 @@ func (oauth *OAuth) Init(fsm *FSM, logger *FileLogger) {
 // Starts the OAuth exchange for eduvpn.
 func (oauth *OAuth) start(name string, authorizationURL string, tokenURL string) error {
 	if !oauth.FSM.HasTransition(OAUTH_STARTED) {
-		return errors.New(fmt.Sprintf("Failed starting oauth, invalid state %s", oauth.FSM.Current.String()))
+		return &FSMWrongStateTransitionError{Got: oauth.FSM.Current, Want: OAUTH_STARTED}
 	}
 	// Generate the state
 	state, stateErr := genState()
 	if stateErr != nil {
-		return &OAuthFailedInitializeError{Err: stateErr}
+		return &OAuthInitializeError{Err: stateErr}
 	}
 
 	// Generate the verifier and challenge
 	verifier, verifierErr := genVerifier()
 	if verifierErr != nil {
-		return &OAuthFailedInitializeError{Err: verifierErr}
+		return &OAuthInitializeError{Err: verifierErr}
 	}
 	challenge := genChallengeS256(verifier)
 
@@ -252,8 +251,8 @@ func (oauth *OAuth) start(name string, authorizationURL string, tokenURL string)
 
 	authURL, urlErr := HTTPConstructURL(authorizationURL, parameters)
 
-	if urlErr != nil { // shouldn't happen
-		panic(urlErr)
+	if urlErr != nil {
+		return &OAuthInitializeError{Err: urlErr}
 	}
 
 	// Fill the struct with the necessary fields filled for the next call to getting the HTTP client
@@ -268,12 +267,12 @@ func (oauth *OAuth) start(name string, authorizationURL string, tokenURL string)
 // Error definitions
 func (oauth *OAuth) Finish() error {
 	if !oauth.FSM.HasTransition(AUTHORIZED) {
-		return errors.New("invalid state to finish oauth")
+		return &FSMWrongStateError{Got: oauth.FSM.Current, Want: AUTHORIZED}
 	}
 	tokenErr := oauth.getTokensWithCallback()
 
 	if tokenErr != nil {
-		return tokenErr
+		return &OAuthFinishError{Err: tokenErr}
 	}
 	oauth.FSM.GoTransition(AUTHORIZED)
 	return nil
@@ -288,13 +287,13 @@ func (oauth *OAuth) Login(name string, authorizationURL string, tokenURL string)
 	authInitializeErr := oauth.start(name, authorizationURL, tokenURL)
 
 	if authInitializeErr != nil {
-		return authInitializeErr
+		return &OAuthLoginError{Err: authInitializeErr}
 	}
 
 	oauthErr := oauth.Finish()
 
 	if oauthErr != nil {
-		return oauthErr
+		return &OAuthLoginError{Err: oauthErr}
 	}
 	return nil
 }
@@ -329,64 +328,96 @@ func (oauth *OAuth) NeedsRelogin() bool {
 type OAuthCancelledCallbackError struct{}
 
 func (e *OAuthCancelledCallbackError) Error() string {
-	return fmt.Sprintf("Client cancelled OAuth")
+	return fmt.Sprintf("client cancelled OAuth")
 }
 
-type OAuthGenStateUnableError struct {
+type OAuthGenStateError struct {
 	Err error
 }
 
-func (e *OAuthGenStateUnableError) Error() string {
-	return fmt.Sprintf("failed generating state with error %v", e.Err)
+func (e *OAuthGenStateError) Error() string {
+	return fmt.Sprintf("failed generating state with error: %v", e.Err)
 }
 
-type OAuthGenVerifierUnableError struct {
+type OAuthGenVerifierError struct {
 	Err error
 }
 
-func (e *OAuthGenVerifierUnableError) Error() string {
-	return fmt.Sprintf("failed generating verifier with error %v", e.Err)
+func (e *OAuthGenVerifierError) Error() string {
+	return fmt.Sprintf("failed generating verifier with error: %v", e.Err)
 }
 
-type OAuthFailedCallbackError struct {
+type OAuthCallbackError struct {
 	Addr string
 	Err  error
 }
 
-func (e *OAuthFailedCallbackError) Error() string {
-	return fmt.Sprintf("failed callback %s with error %v", e.Addr, e.Err)
+func (e *OAuthCallbackError) Error() string {
+	return fmt.Sprintf("failed callback: %s with error: %v", e.Addr, e.Err)
 }
 
-type OAuthFailedCallbackParameterError struct {
+type OAuthCallbackParameterError struct {
 	Parameter string
 	URL       string
 }
 
-func (e *OAuthFailedCallbackParameterError) Error() string {
-	return fmt.Sprintf("failed retrieving parameter %s in url %s", e.Parameter, e.URL)
+func (e *OAuthCallbackParameterError) Error() string {
+	return fmt.Sprintf("failed retrieving parameter: %s in url: %s", e.Parameter, e.URL)
 }
 
-type OAuthFailedCallbackStateMatchError struct {
+type OAuthCallbackStateMatchError struct {
 	State         string
 	ExpectedState string
 }
 
-func (e *OAuthFailedCallbackStateMatchError) Error() string {
-	return fmt.Sprintf("failed matching state, got %s, want %s", e.State, e.ExpectedState)
+func (e *OAuthCallbackStateMatchError) Error() string {
+	return fmt.Sprintf("failed matching state, got: %s, want: %s", e.State, e.ExpectedState)
 }
 
-type OAuthFailedCallbackGetTokensError struct {
+type OAuthCallbackGetTokensError struct {
 	Err error
 }
 
-func (e *OAuthFailedCallbackGetTokensError) Error() string {
-	return fmt.Sprintf("failed getting tokens with error %v", e.Err)
+func (e *OAuthCallbackGetTokensError) Error() string {
+	return fmt.Sprintf("failed getting tokens with error: %v", e.Err)
 }
 
-type OAuthFailedInitializeError struct {
+type OAuthFinishError struct {
 	Err error
 }
 
-func (e *OAuthFailedInitializeError) Error() string {
-	return fmt.Sprintf("failed initializing OAuth with error %v", e.Err)
+func (e *OAuthFinishError) Error() string {
+	return fmt.Sprintf("failed finishing OAuth with error: %v", e.Err)
+}
+
+type OAuthLoginError struct {
+	Err error
+}
+
+func (e *OAuthLoginError) Error() string {
+	return fmt.Sprintf("failed OAuth logging in with error: %v", e.Err)
+}
+
+type OAuthInitializeError struct {
+	Err error
+}
+
+func (e *OAuthInitializeError) Error() string {
+	return fmt.Sprintf("failed initializing OAuth with error: %v", e.Err)
+}
+
+type OAuthAuthError struct {
+	Err error
+}
+
+func (e *OAuthAuthError) Error() string {
+	return fmt.Sprintf("failed getting tokens with auth code for OAuth with error: %v", e.Err)
+}
+
+type OAuthRefreshError struct {
+	Err error
+}
+
+func (e *OAuthRefreshError) Error() string {
+	return fmt.Sprintf("failed refreshing tokens for OAuth with error: %v", e.Err)
 }