1 files changed, 144 insertions, 0 deletions
diff --git a/config-model-api/src/main/java/com/yahoo/config/application/api/ValidationOverrides.java b/config-model-api/src/main/java/com/yahoo/config/application/api/ValidationOverrides.java
new file mode 100644
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+++ b/config-model-api/src/main/java/com/yahoo/config/application/api/ValidationOverrides.java
@@ -0,0 +1,144 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.application.api;
+
+import com.google.common.collect.ImmutableList;
+import com.yahoo.text.XML;
+import org.w3c.dom.Element;
+
+import java.io.Reader;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneOffset;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * A set of allows which suppresses specific validations in limited time periods.
+ * This is useful to be able to complete a deployment in cases where the application
+ * owner believes that the changes to be deployed have acceptable consequences.
+ * Immutable.
+ *
+ * @author bratseth
+ */
+public class ValidationOverrides {
+
+    private final List<Allow> overrides;
+
+    /** Instant to use as "now". This is a field to allow unit testing. */
+    private final Instant now;
+
+    /** Creates validation overrides for the current instant */
+    public ValidationOverrides(List<Allow> overrides) {
+        this(overrides, Instant.now());
+    }
+
+    public ValidationOverrides(List<Allow> overrides, Instant now) {
+        this.overrides = ImmutableList.copyOf(overrides);
+        this.now = now;
+        for (Allow override : overrides)
+            if (now.plus(Duration.ofDays(30)).isBefore(override.until))
+                throw new IllegalArgumentException(override + " is too far in the future: Max 30 days is allowed");
+    }
+
+    /** Throws a ValidationException unless this validation is overridden at this time */
+    public void invalid(ValidationId validationId, String message) {
+        if ( ! allows(validationId))
+            throw new ValidationException(validationId, message);
+    }
+
+    public boolean allows(String validationIdString) {
+        Optional<ValidationId> validationId = ValidationId.from(validationIdString);
+        if ( ! validationId.isPresent()) return false; // unknown id -> not allowed
+        return allows(validationId.get());
+    }
+
+    /** Returns whether the given (assumed invalid) change is allowed by this at the moment */
+    public boolean allows(ValidationId validationId) {
+        for (Allow override : overrides)
+            if (override.allows(validationId, now))
+                return true;
+        return false;
+    }
+
+    public static ValidationOverrides empty() { return new ValidationOverrides(ImmutableList.of()); }
+
+    /**
+     * Returns a ValidationOverrides instance with the content of the given Reader.
+     * An empty ValidationOverrides is returned if the argument is empty.
+     *
+     * @param reader the reader which optionally contains a validation-overrides XML structure
+     * @param now the instant to use as "now", settable for unit testing
+     * @return a ValidationOverrides from the argument
+     * @throws IllegalArgumentException if the validation-allows.xml file exists but is invalid
+     */
+    public static ValidationOverrides read(Optional<Reader> reader, Instant now) {
+        if ( ! reader.isPresent()) return ValidationOverrides.empty();
+
+        try {
+            // Assume valid structure is ensured by schema validation
+            Element root = XML.getDocument(reader.get()).getDocumentElement();
+            List<ValidationOverrides.Allow> overrides = new ArrayList<>();
+            for (Element allow : XML.getChildren(root, "allow")) {
+                Instant until = LocalDate.parse(allow.getAttribute("until"), DateTimeFormatter.ISO_DATE)
+                        .atStartOfDay().atZone(ZoneOffset.UTC).toInstant()
+                        .plus(Duration.ofDays(1)); // Make the override valid *on* the "until" date
+                Optional<ValidationId> validationId = ValidationId.from(XML.getValue(allow));
+                if (validationId.isPresent()) // skip unknonw ids as they may be valid for other model versions
+                    overrides.add(new ValidationOverrides.Allow(validationId.get(), until));
+            }
+            return new ValidationOverrides(overrides, now);
+        }
+        catch (IllegalArgumentException e) {
+            throw new IllegalArgumentException("validation-overrides is invalid", e);
+        }
+    }
+
+    /** A validation override which allows a particular change. Immutable. */
+    public static class Allow {
+
+        private final ValidationId validationId;
+        private final Instant until;
+
+        public Allow(ValidationId validationId, Instant until) {
+            this.validationId = validationId;
+            this.until = until;
+        }
+
+        public boolean allows(ValidationId validationId, Instant now) {
+            return this.validationId.equals(validationId) && now.isBefore(until);
+        }
+
+        @Override
+        public String toString() { return "allow '" + validationId + "' until " + until; }
+
+    }
+
+    /**
+     * A deployment validation exception.
+     * Deployment validations can be {@link ValidationOverrides overridden} based on their id.
+     * The purpose of this exception is to model that id as a separate field.
+     */
+    public static class ValidationException extends IllegalArgumentException {
+
+        static final long serialVersionUID = 789984668;
+
+        private final ValidationId validationId;
+
+        private ValidationException(ValidationId validationId, String message) {
+            super(message);
+            this.validationId = validationId;
+        }
+
+        /** Returns the unique id of this validation, which can be used to {@link ValidationOverrides override} it */
+        public ValidationId validationId() { return validationId; }
+
+        /** Returns "validationId: message" */
+        @Override
+        public String getMessage() { return validationId + ": " + super.getMessage(); }
+
+    }
+
+}