validation: add generic validation framework (#2480)

* [wip] validation framework Signed-off-by: Moritz Sanft <[email protected]> * [wip] wip Signed-off-by: Moritz Sanft <[email protected]> * working for shallow structs!!! Signed-off-by: Moritz Sanft <[email protected]> * fix needle pointer deref Signed-off-by: Moritz Sanft <[email protected]> * add comment Signed-off-by: Moritz Sanft <[email protected]> * fix nested structs Signed-off-by: Moritz Sanft <[email protected]> * fix nested struct pointers Signed-off-by: Moritz Sanft <[email protected]> * add tests Signed-off-by: Moritz Sanft <[email protected]> * fix slices / arrays Signed-off-by: Moritz Sanft <[email protected]> * fix struct parsing Signed-off-by: Moritz Sanft <[email protected]> * extend tests Signed-off-by: Moritz Sanft <[email protected]> * expose API Signed-off-by: Moritz Sanft <[email protected]> * extend in-package documentation Signed-off-by: Moritz Sanft <[email protected]> * linter fixes Signed-off-by: Moritz Sanft <[email protected]> * fix naming Signed-off-by: Moritz Sanft <[email protected]> * add missing license headers Signed-off-by: Moritz Sanft <[email protected]> * Apply suggestions from code review Co-authored-by: Daniel Weiße <[email protected]> * align with review Signed-off-by: Moritz Sanft <[email protected]> --------- Signed-off-by: Moritz Sanft <[email protected]> Co-authored-by: Daniel Weiße <[email protected]>
edgelesssys · Oct 24, 2023 · a104936 · a104936
1 parent 2f745a2
commit a104936
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diff --git a/internal/validation/BUILD.bazel b/internal/validation/BUILD.bazel
@@ -0,0 +1,26 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("//bazel/go:go_test.bzl", "go_test")
+
+go_library(
+    name = "validation",
+    srcs = [
+        "constraints.go",
+        "errors.go",
+        "validation.go",
+    ],
+    importpath = "github.com/edgelesssys/constellation/v2/internal/validation",
+    visibility = ["//:__subpackages__"],
+)
+
+go_test(
+    name = "validation_test",
+    srcs = [
+        "errors_test.go",
+        "validation_test.go",
+    ],
+    embed = [":validation"],
+    deps = [
+        "@com_github_stretchr_testify//assert",
+        "@com_github_stretchr_testify//require",
+    ],
+)
diff --git a/internal/validation/constraints.go b/internal/validation/constraints.go
@@ -0,0 +1,153 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package validation
+
+import (
+	"fmt"
+	"reflect"
+	"regexp"
+)
+
+// Constraint is a constraint on a document or a field of a document.
+type Constraint struct {
+	// Satisfied returns no error if the constraint is satisfied.
+	// Otherwise, it returns the reason why the constraint is not satisfied.
+	Satisfied func() error
+}
+
+/*
+WithFieldTrace adds a well-formatted trace to the field to the error message
+shown when the constraint is not satisfied. Both "doc" and "field" must be pointers:
+  - "doc" must be a pointer to the top level document
+  - "field" must be a pointer to the field to be validated
+
+Example for a non-pointer field:
+
+	Equal(d.IntField, 42).WithFieldTrace(d, &d.IntField)
+
+Example for a pointer field:
+
+	NotEmpty(d.StrPtrField).WithFieldTrace(d, d.StrPtrField)
+
+Due to Go's addressability limititations regarding maps, if a map field is
+to be validated, WithMapFieldTrace must be used instead of WithFieldTrace.
+*/
+func (c *Constraint) WithFieldTrace(doc any, field any) Constraint {
+	// we only want to dereference the needle once to dereference the pointer
+	// used to pass it to the function without losing reference to it, as the
+	// needle could be an arbitrarily long chain of pointers. The same
+	// applies to the haystack.
+	derefedField := pointerDeref(reflect.ValueOf(field))
+	fieldRef := referenceableValue{
+		value: derefedField,
+		addr:  derefedField.UnsafeAddr(),
+		_type: derefedField.Type(),
+	}
+	derefedDoc := pointerDeref(reflect.ValueOf(doc))
+	docRef := referenceableValue{
+		value: derefedDoc,
+		addr:  derefedDoc.UnsafeAddr(),
+		_type: derefedDoc.Type(),
+	}
+	return c.withTrace(docRef, fieldRef)
+}
+
+/*
+WithMapFieldTrace adds a well-formatted trace to the map field to the error message
+shown when the constraint is not satisfied. Both "doc" and "field" must be pointers:
+  - "doc" must be a pointer to the top level document
+  - "field" must be a pointer to the map containing the field to be validated
+  - "mapKey" must be the key of the field to be validated in the map pointed to by "field"
+
+Example:
+
+	Equal(d.IntField, 42).WithMapFieldTrace(d, &d.MapField, mapKey)
+
+For non-map fields, WithFieldTrace should be used instead of WithMapFieldTrace.
+*/
+func (c *Constraint) WithMapFieldTrace(doc any, field any, mapKey string) Constraint {
+	// we only want to dereference the needle once to dereference the pointer
+	// used to pass it to the function without losing reference to it, as the
+	// needle could be an arbitrarily long chain of pointers. The same
+	// applies to the haystack.
+	derefedField := pointerDeref(reflect.ValueOf(field))
+	fieldRef := referenceableValue{
+		value:  derefedField,
+		addr:   derefedField.UnsafeAddr(),
+		_type:  derefedField.Type(),
+		mapKey: mapKey,
+	}
+	derefedDoc := pointerDeref(reflect.ValueOf(doc))
+	docRef := referenceableValue{
+		value: derefedDoc,
+		addr:  derefedDoc.UnsafeAddr(),
+		_type: derefedDoc.Type(),
+	}
+	return c.withTrace(docRef, fieldRef)
+}
+
+// withTrace wraps the constraint's error message with a well-formatted trace.
+func (c *Constraint) withTrace(docRef, fieldRef referenceableValue) Constraint {
+	return Constraint{
+		Satisfied: func() error {
+			if err := c.Satisfied(); err != nil {
+				return newError(docRef, fieldRef, err)
+			}
+			return nil
+		},
+	}
+}
+
+// MatchRegex is a constraint that if s matches regex.
+func MatchRegex(s string, regex string) *Constraint {
+	return &Constraint{
+		Satisfied: func() error {
+			if !regexp.MustCompile(regex).MatchString(s) {
+				return fmt.Errorf("%s must match the pattern %s", s, regex)
+			}
+			return nil
+		},
+	}
+}
+
+// Equal is a constraint that if s is equal to t.
+func Equal[T comparable](s T, t T) *Constraint {
+	return &Constraint{
+		Satisfied: func() error {
+			if s != t {
+				return fmt.Errorf("%v must be equal to %v", s, t)
+			}
+			return nil
+		},
+	}
+}
+
+// NotEmpty is a constraint that if s is not empty.
+func NotEmpty[T comparable](s T) *Constraint {
+	return &Constraint{
+		Satisfied: func() error {
+			var zero T
+			if s == zero {
+				return fmt.Errorf("%v must not be empty", s)
+			}
+			return nil
+		},
+	}
+}
+
+// Empty is a constraint that if s is empty.
+func Empty[T comparable](s T) *Constraint {
+	return &Constraint{
+		Satisfied: func() error {
+			var zero T
+			if s != zero {
+				return fmt.Errorf("%v must be empty", s)
+			}
+			return nil
+		},
+	}
+}