Add OIDC login support for Google and Microsoft providers

Implements OpenID Connect authentication flow with PKCE, JWT verification, and enterprise-only account restrictions. Adds OIDC service with JWKS caching and state management, HTTP handlers for login/callback flows, GraphQL query for available providers, and sign-in UI integration.

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/coredata/oidc_state.go

@@ -0,0 +1,137 @@
+// Copyright (c) 2025 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package coredata
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+	"go.gearno.de/kit/pg"
+)
+
+type (
+	OIDCProvider string
+
+	OIDCState struct {
+		ID           string       `db:"id"`
+		Provider     OIDCProvider `db:"provider"`
+		Nonce        string       `db:"nonce"`
+		CodeVerifier string       `db:"code_verifier"`
+		ContinueURL  string       `db:"continue_url"`
+		CreatedAt    time.Time    `db:"created_at"`
+		ExpiresAt    time.Time    `db:"expires_at"`
+	}
+)
+
+const (
+	OIDCProviderGoogle    OIDCProvider = "GOOGLE"
+	OIDCProviderMicrosoft OIDCProvider = "MICROSOFT"
+)
+
+func (p OIDCProvider) IsValid() bool {
+	switch p {
+	case OIDCProviderGoogle, OIDCProviderMicrosoft:
+		return true
+	}
+	return false
+}
+
+func (p OIDCProvider) String() string { return string(p) }
+
+func (p *OIDCProvider) UnmarshalText(text []byte) error {
+	*p = OIDCProvider(text)
+	if !p.IsValid() {
+		return fmt.Errorf("%s is not a valid OIDCProvider", string(text))
+	}
+	return nil
+}
+
+func (p OIDCProvider) MarshalText() ([]byte, error) {
+	return []byte(p.String()), nil
+}
+
+func (s *OIDCState) Insert(ctx context.Context, conn pg.Conn) error {
+	query := `
+INSERT INTO iam_oidc_states (id, provider, nonce, code_verifier, continue_url, created_at, expires_at)
+VALUES (@id, @provider, @nonce, @code_verifier, @continue_url, @created_at, @expires_at)
+`
+
+	args := pgx.StrictNamedArgs{
+		"id":            s.ID,
+		"provider":      s.Provider,
+		"nonce":         s.Nonce,
+		"code_verifier": s.CodeVerifier,
+		"continue_url":  s.ContinueURL,
+		"created_at":    s.CreatedAt,
+		"expires_at":    s.ExpiresAt,
+	}
+
+	_, err := conn.Exec(ctx, query, args)
+	if err != nil {
+		return fmt.Errorf("cannot insert oidc_state: %w", err)
+	}
+
+	return nil
+}
+
+func (s *OIDCState) LoadByIDForUpdate(ctx context.Context, conn pg.Conn, id string) error {
+	query := `
+SELECT id, provider, nonce, code_verifier, continue_url, created_at, expires_at
+FROM iam_oidc_states
+WHERE id = @id
+FOR UPDATE
+`
+
+	rows, err := conn.Query(ctx, query, pgx.StrictNamedArgs{"id": id})
+	if err != nil {
+		return fmt.Errorf("cannot query oidc_state: %w", err)
+	}
+
+	state, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[OIDCState])
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return ErrResourceNotFound
+		}
+		return fmt.Errorf("cannot collect oidc_state: %w", err)
+	}
+
+	*s = state
+	return nil
+}
+
+func (s *OIDCState) Delete(ctx context.Context, conn pg.Conn) error {
+	query := `DELETE FROM iam_oidc_states WHERE id = @id`
+
+	_, err := conn.Exec(ctx, query, pgx.StrictNamedArgs{"id": s.ID})
+	if err != nil {
+		return fmt.Errorf("cannot delete oidc_state: %w", err)
+	}
+
+	return nil
+}
+
+func DeleteExpiredOIDCStates(ctx context.Context, conn pg.Conn, now time.Time) (int64, error) {
+	query := `DELETE FROM iam_oidc_states WHERE expires_at < @now`
+
+	result, err := conn.Exec(ctx, query, pgx.StrictNamedArgs{"now": now})
+	if err != nil {
+		return 0, fmt.Errorf("cannot delete expired oidc_states: %w", err)
+	}
+
+	return result.RowsAffected(), nil
+}