Monitor Conditions (#5048)

server/client.js

@@ -213,6 +213,32 @@ async function sendRemoteBrowserList(socket) {
     return list;
 }
 
+/**
+ * Send list of monitor types to client
+ * @param {Socket} socket Socket.io socket instance
+ * @returns {Promise<void>}
+ */
+async function sendMonitorTypeList(socket) {
+    const result = Object.entries(UptimeKumaServer.monitorTypeList).map(([ key, type ]) => {
+        return [ key, {
+            supportsConditions: type.supportsConditions,
+            conditionVariables: type.conditionVariables.map(v => {
+                return {
+                    id: v.id,
+                    operators: v.operators.map(o => {
+                        return {
+                            id: o.id,
+                            caption: o.caption,
+                        };
+                    }),
+                };
+            }),
+        }];
+    });
+
+    io.to(socket.userID).emit("monitorTypeList", Object.fromEntries(result));
+}
+
 module.exports = {
     sendNotificationList,
     sendImportantHeartbeatList,
@@ -222,4 +248,5 @@ module.exports = {
     sendInfo,
     sendDockerHostList,
     sendRemoteBrowserList,
+    sendMonitorTypeList,
 };

server/model/monitor.js

@@ -164,6 +164,7 @@ class Monitor extends BeanModel {
             snmpOid: this.snmpOid,
             jsonPathOperator: this.jsonPathOperator,
             snmpVersion: this.snmpVersion,
+            conditions: JSON.parse(this.conditions),
         };
 
         if (includeSensitiveData) {

server/monitor-conditions/evaluator.js

@@ -0,0 +1,71 @@
+const { ConditionExpressionGroup, ConditionExpression, LOGICAL } = require("./expression");
+const { operatorMap } = require("./operators");
+
+/**
+ * @param {ConditionExpression} expression Expression to evaluate
+ * @param {object} context Context to evaluate against; These are values for variables in the expression
+ * @returns {boolean} Whether the expression evaluates true or false
+ * @throws {Error}
+ */
+function evaluateExpression(expression, context) {
+    /**
+     * @type {import("./operators").ConditionOperator|null}
+     */
+    const operator = operatorMap.get(expression.operator) || null;
+    if (operator === null) {
+        throw new Error("Unexpected expression operator ID '" + expression.operator + "'. Expected one of [" + operatorMap.keys().join(",") + "]");
+    }
+
+    if (!Object.prototype.hasOwnProperty.call(context, expression.variable)) {
+        throw new Error("Variable missing in context: " + expression.variable);
+    }
+
+    return operator.test(context[expression.variable], expression.value);
+}
+
+/**
+ * @param {ConditionExpressionGroup} group Group of expressions to evaluate
+ * @param {object} context Context to evaluate against; These are values for variables in the expression
+ * @returns {boolean} Whether the group evaluates true or false
+ * @throws {Error}
+ */
+function evaluateExpressionGroup(group, context) {
+    if (!group.children.length) {
+        throw new Error("ConditionExpressionGroup must contain at least one child.");
+    }
+
+    let result = null;
+
+    for (const child of group.children) {
+        let childResult;
+
+        if (child instanceof ConditionExpression) {
+            childResult = evaluateExpression(child, context);
+        } else if (child instanceof ConditionExpressionGroup) {
+            childResult = evaluateExpressionGroup(child, context);
+        } else {
+            throw new Error("Invalid child type in ConditionExpressionGroup. Expected ConditionExpression or ConditionExpressionGroup");
+        }
+
+        if (result === null) {
+            result = childResult; // Initialize result with the first child's result
+        } else if (child.andOr === LOGICAL.OR) {
+            result = result || childResult;
+        } else if (child.andOr === LOGICAL.AND) {
+            result = result && childResult;
+        } else {
+            throw new Error("Invalid logical operator in child of ConditionExpressionGroup. Expected 'and' or 'or'. Got '" + group.andOr + "'");
+        }
+    }
+
+    if (result === null) {
+        throw new Error("ConditionExpressionGroup did not result in a boolean.");
+    }
+
+    return result;
+}
+
+module.exports = {
+    evaluateExpression,
+    evaluateExpressionGroup,
+};

server/monitor-conditions/expression.js

@@ -0,0 +1,111 @@
+/**
+ * @readonly
+ * @enum {string}
+ */
+const LOGICAL = {
+    AND: "and",
+    OR: "or",
+};
+
+/**
+ * Recursively processes an array of raw condition objects and populates the given parent group with
+ * corresponding ConditionExpression or ConditionExpressionGroup instances.
+ * @param {Array} conditions Array of raw condition objects, where each object represents either a group or an expression.
+ * @param {ConditionExpressionGroup} parentGroup The parent group to which the instantiated ConditionExpression or ConditionExpressionGroup objects will be added.
+ * @returns {void}
+ */
+function processMonitorConditions(conditions, parentGroup) {
+    conditions.forEach(condition => {
+        const andOr = condition.andOr === LOGICAL.OR ? LOGICAL.OR : LOGICAL.AND;
+
+        if (condition.type === "group") {
+            const group = new ConditionExpressionGroup([], andOr);
+
+            // Recursively process the group's children
+            processMonitorConditions(condition.children, group);
+
+            parentGroup.children.push(group);
+        } else if (condition.type === "expression") {
+            const expression = new ConditionExpression(condition.variable, condition.operator, condition.value, andOr);
+            parentGroup.children.push(expression);
+        }
+    });
+}
+
+class ConditionExpressionGroup {
+    /**
+     * @type {ConditionExpressionGroup[]|ConditionExpression[]} Groups and/or expressions to test
+     */
+    children = [];
+
+    /**
+     * @type {LOGICAL} Connects group result with previous group/expression results
+     */
+    andOr;
+
+    /**
+     * @param {ConditionExpressionGroup[]|ConditionExpression[]} children Groups and/or expressions to test
+     * @param {LOGICAL} andOr Connects group result with previous group/expression results
+     */
+    constructor(children = [], andOr = LOGICAL.AND) {
+        this.children = children;
+        this.andOr = andOr;
+    }
+
+    /**
+     * @param {Monitor} monitor Monitor instance
+     * @returns {ConditionExpressionGroup|null} A ConditionExpressionGroup with the Monitor's conditions
+     */
+    static fromMonitor(monitor) {
+        const conditions = JSON.parse(monitor.conditions);
+        if (conditions.length === 0) {
+            return null;
+        }
+
+        const root = new ConditionExpressionGroup();
+        processMonitorConditions(conditions, root);
+
+        return root;
+    }
+}
+
+class ConditionExpression {
+    /**
+     * @type {string} ID of variable
+     */
+    variable;
+
+    /**
+     * @type {string} ID of operator
+     */
+    operator;
+
+    /**
+     * @type {string} Value to test with the operator
+     */
+    value;
+
+    /**
+     * @type {LOGICAL} Connects expression result with previous group/expression results
+     */
+    andOr;
+
+    /**
+     * @param {string} variable ID of variable to test against
+     * @param {string} operator ID of operator to test the variable with
+     * @param {string} value Value to test with the operator
+     * @param {LOGICAL} andOr Connects expression result with previous group/expression results
+     */
+    constructor(variable, operator, value, andOr = LOGICAL.AND) {
+        this.variable = variable;
+        this.operator = operator;
+        this.value = value;
+        this.andOr = andOr;
+    }
+}
+
+module.exports = {
+    LOGICAL,
+    ConditionExpressionGroup,
+    ConditionExpression,
+};

server/monitor-conditions/operators.js

@@ -0,0 +1,318 @@
+class ConditionOperator {
+    id = undefined;
+    caption = undefined;
+
+    /**
+     * @type {mixed} variable
+     * @type {mixed} value
+     */
+    test(variable, value) {
+        throw new Error("You need to override test()");
+    }
+}
+
+const OP_STR_EQUALS = "equals";
+
+const OP_STR_NOT_EQUALS = "not_equals";
+
+const OP_CONTAINS = "contains";
+
+const OP_NOT_CONTAINS = "not_contains";
+
+const OP_STARTS_WITH = "starts_with";
+
+const OP_NOT_STARTS_WITH = "not_starts_with";
+
+const OP_ENDS_WITH = "ends_with";
+
+const OP_NOT_ENDS_WITH = "not_ends_with";
+
+const OP_NUM_EQUALS = "num_equals";
+
+const OP_NUM_NOT_EQUALS = "num_not_equals";
+
+const OP_LT = "lt";
+
+const OP_GT = "gt";
+
+const OP_LTE = "lte";
+
+const OP_GTE = "gte";
+
+/**
+ * Asserts a variable is equal to a value.
+ */
+class StringEqualsOperator extends ConditionOperator {
+    id = OP_STR_EQUALS;
+    caption = "equals";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable === value;
+    }
+}
+
+/**
+ * Asserts a variable is not equal to a value.
+ */
+class StringNotEqualsOperator extends ConditionOperator {
+    id = OP_STR_NOT_EQUALS;
+    caption = "not equals";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable !== value;
+    }
+}
+
+/**
+ * Asserts a variable contains a value.
+ * Handles both Array and String variable types.
+ */
+class ContainsOperator extends ConditionOperator {
+    id = OP_CONTAINS;
+    caption = "contains";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        if (Array.isArray(variable)) {
+            return variable.includes(value);
+        }
+
+        return variable.indexOf(value) !== -1;
+    }
+}
+
+/**
+ * Asserts a variable does not contain a value.
+ * Handles both Array and String variable types.
+ */
+class NotContainsOperator extends ConditionOperator {
+    id = OP_NOT_CONTAINS;
+    caption = "not contains";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        if (Array.isArray(variable)) {
+            return !variable.includes(value);
+        }
+
+        return variable.indexOf(value) === -1;
+    }
+}
+
+/**
+ * Asserts a variable starts with a value.
+ */
+class StartsWithOperator extends ConditionOperator {
+    id = OP_STARTS_WITH;
+    caption = "starts with";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable.startsWith(value);
+    }
+}
+
+/**
+ * Asserts a variable does not start with a value.
+ */
+class NotStartsWithOperator extends ConditionOperator {
+    id = OP_NOT_STARTS_WITH;
+    caption = "not starts with";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return !variable.startsWith(value);
+    }
+}
+
+/**
+ * Asserts a variable ends with a value.
+ */
+class EndsWithOperator extends ConditionOperator {
+    id = OP_ENDS_WITH;
+    caption = "ends with";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable.endsWith(value);
+    }
+}
+
+/**
+ * Asserts a variable does not end with a value.
+ */
+class NotEndsWithOperator extends ConditionOperator {
+    id = OP_NOT_ENDS_WITH;
+    caption = "not ends with";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return !variable.endsWith(value);
+    }
+}
+
+/**
+ * Asserts a numeric variable is equal to a value.
+ */
+class NumberEqualsOperator extends ConditionOperator {
+    id = OP_NUM_EQUALS;
+    caption = "equals";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable === Number(value);
+    }
+}
+
+/**
+ * Asserts a numeric variable is not equal to a value.
+ */
+class NumberNotEqualsOperator extends ConditionOperator {
+    id = OP_NUM_NOT_EQUALS;
+    caption = "not equals";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable !== Number(value);
+    }
+}
+
+/**
+ * Asserts a variable is less than a value.
+ */
+class LessThanOperator extends ConditionOperator {
+    id = OP_LT;
+    caption = "less than";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable < Number(value);
+    }
+}
+
+/**
+ * Asserts a variable is greater than a value.
+ */
+class GreaterThanOperator extends ConditionOperator {
+    id = OP_GT;
+    caption = "greater than";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable > Number(value);
+    }
+}
+
+/**
+ * Asserts a variable is less than or equal to a value.
+ */
+class LessThanOrEqualToOperator extends ConditionOperator {
+    id = OP_LTE;
+    caption = "less than or equal to";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable <= Number(value);
+    }
+}
+
+/**
+ * Asserts a variable is greater than or equal to a value.
+ */
+class GreaterThanOrEqualToOperator extends ConditionOperator {
+    id = OP_GTE;
+    caption = "greater than or equal to";
+
+    /**
+     * @inheritdoc
+     */
+    test(variable, value) {
+        return variable >= Number(value);
+    }
+}
+
+const operatorMap = new Map([
+    [ OP_STR_EQUALS, new StringEqualsOperator ],
+    [ OP_STR_NOT_EQUALS, new StringNotEqualsOperator ],
+    [ OP_CONTAINS, new ContainsOperator ],
+    [ OP_NOT_CONTAINS, new NotContainsOperator ],
+    [ OP_STARTS_WITH, new StartsWithOperator ],
+    [ OP_NOT_STARTS_WITH, new NotStartsWithOperator ],
+    [ OP_ENDS_WITH, new EndsWithOperator ],
+    [ OP_NOT_ENDS_WITH, new NotEndsWithOperator ],
+    [ OP_NUM_EQUALS, new NumberEqualsOperator ],
+    [ OP_NUM_NOT_EQUALS, new NumberNotEqualsOperator ],
+    [ OP_LT, new LessThanOperator ],
+    [ OP_GT, new GreaterThanOperator ],
+    [ OP_LTE, new LessThanOrEqualToOperator ],
+    [ OP_GTE, new GreaterThanOrEqualToOperator ],
+]);
+
+const defaultStringOperators = [
+    operatorMap.get(OP_STR_EQUALS),
+    operatorMap.get(OP_STR_NOT_EQUALS),
+    operatorMap.get(OP_CONTAINS),
+    operatorMap.get(OP_NOT_CONTAINS),
+    operatorMap.get(OP_STARTS_WITH),
+    operatorMap.get(OP_NOT_STARTS_WITH),
+    operatorMap.get(OP_ENDS_WITH),
+    operatorMap.get(OP_NOT_ENDS_WITH)
+];
+
+const defaultNumberOperators = [
+    operatorMap.get(OP_NUM_EQUALS),
+    operatorMap.get(OP_NUM_NOT_EQUALS),
+    operatorMap.get(OP_LT),
+    operatorMap.get(OP_GT),
+    operatorMap.get(OP_LTE),
+    operatorMap.get(OP_GTE)
+];
+
+module.exports = {
+    OP_STR_EQUALS,
+    OP_STR_NOT_EQUALS,
+    OP_CONTAINS,
+    OP_NOT_CONTAINS,
+    OP_STARTS_WITH,
+    OP_NOT_STARTS_WITH,
+    OP_ENDS_WITH,
+    OP_NOT_ENDS_WITH,
+    OP_NUM_EQUALS,
+    OP_NUM_NOT_EQUALS,
+    OP_LT,
+    OP_GT,
+    OP_LTE,
+    OP_GTE,
+    operatorMap,
+    defaultStringOperators,
+    defaultNumberOperators,
+    ConditionOperator,
+};

server/monitor-conditions/variables.js

@@ -0,0 +1,31 @@
+/**
+ * Represents a variable used in a condition and the set of operators that can be applied to this variable.
+ *
+ * A `ConditionVariable` holds the ID of the variable and a list of operators that define how this variable can be evaluated
+ * in conditions. For example, if the variable is a request body or a specific field in a request, the operators can include
+ * operations such as equality checks, comparisons, or other custom evaluations.
+ */
+class ConditionVariable {
+    /**
+     * @type {string}
+     */
+    id;
+
+    /**
+     * @type {import("./operators").ConditionOperator[]}
+     */
+    operators = {};
+
+    /**
+     * @param {string} id ID of variable
+     * @param {import("./operators").ConditionOperator[]} operators Operators the condition supports
+     */
+    constructor(id, operators = []) {
+        this.id = id;
+        this.operators = operators;
+    }
+}
+
+module.exports = {
+    ConditionVariable,
+};

server/monitor-types/dns.js

@@ -1,12 +1,22 @@
 const { MonitorType } = require("./monitor-type");
-const { UP } = require("../../src/util");
+const { UP, DOWN } = require("../../src/util");
 const dayjs = require("dayjs");
 const { dnsResolve } = require("../util-server");
 const { R } = require("redbean-node");
+const { ConditionVariable } = require("../monitor-conditions/variables");
+const { defaultStringOperators } = require("../monitor-conditions/operators");
+const { ConditionExpressionGroup } = require("../monitor-conditions/expression");
+const { evaluateExpressionGroup } = require("../monitor-conditions/evaluator");
 
 class DnsMonitorType extends MonitorType {
     name = "dns";
 
+    supportsConditions = true;
+
+    conditionVariables = [
+        new ConditionVariable("record", defaultStringOperators ),
+    ];
+
     /**
      * @inheritdoc
      */
@@ -17,28 +27,48 @@ class DnsMonitorType extends MonitorType {
         let dnsRes = await dnsResolve(monitor.hostname, monitor.dns_resolve_server, monitor.port, monitor.dns_resolve_type);
         heartbeat.ping = dayjs().valueOf() - startTime;
 
-        if (monitor.dns_resolve_type === "A" || monitor.dns_resolve_type === "AAAA" || monitor.dns_resolve_type === "TXT" || monitor.dns_resolve_type === "PTR") {
-            dnsMessage += "Records: ";
-            dnsMessage += dnsRes.join(" | ");
-        } else if (monitor.dns_resolve_type === "CNAME" || monitor.dns_resolve_type === "PTR") {
-            dnsMessage += dnsRes[0];
-        } else if (monitor.dns_resolve_type === "CAA") {
-            dnsMessage += dnsRes[0].issue;
-        } else if (monitor.dns_resolve_type === "MX") {
-            dnsRes.forEach(record => {
-                dnsMessage += `Hostname: ${record.exchange} - Priority: ${record.priority} | `;
-            });
-            dnsMessage = dnsMessage.slice(0, -2);
-        } else if (monitor.dns_resolve_type === "NS") {
-            dnsMessage += "Servers: ";
-            dnsMessage += dnsRes.join(" | ");
-        } else if (monitor.dns_resolve_type === "SOA") {
-            dnsMessage += `NS-Name: ${dnsRes.nsname} | Hostmaster: ${dnsRes.hostmaster} | Serial: ${dnsRes.serial} | Refresh: ${dnsRes.refresh} | Retry: ${dnsRes.retry} | Expire: ${dnsRes.expire} | MinTTL: ${dnsRes.minttl}`;
-        } else if (monitor.dns_resolve_type === "SRV") {
-            dnsRes.forEach(record => {
-                dnsMessage += `Name: ${record.name} | Port: ${record.port} | Priority: ${record.priority} | Weight: ${record.weight} | `;
-            });
-            dnsMessage = dnsMessage.slice(0, -2);
+        const conditions = ConditionExpressionGroup.fromMonitor(monitor);
+        let conditionsResult = true;
+        const handleConditions = (data) => conditions ? evaluateExpressionGroup(conditions, data) : true;
+
+        switch (monitor.dns_resolve_type) {
+            case "A":
+            case "AAAA":
+            case "TXT":
+            case "PTR":
+                dnsMessage = `Records: ${dnsRes.join(" | ")}`;
+                conditionsResult = dnsRes.some(record => handleConditions({ record }));
+                break;
+
+            case "CNAME":
+                dnsMessage = dnsRes[0];
+                conditionsResult = handleConditions({ record: dnsRes[0] });
+                break;
+
+            case "CAA":
+                dnsMessage = dnsRes[0].issue;
+                conditionsResult = handleConditions({ record: dnsRes[0].issue });
+                break;
+
+            case "MX":
+                dnsMessage = dnsRes.map(record => `Hostname: ${record.exchange} - Priority: ${record.priority}`).join(" | ");
+                conditionsResult = dnsRes.some(record => handleConditions({ record: record.exchange }));
+                break;
+
+            case "NS":
+                dnsMessage = `Servers: ${dnsRes.join(" | ")}`;
+                conditionsResult = dnsRes.some(record => handleConditions({ record }));
+                break;
+
+            case "SOA":
+                dnsMessage = `NS-Name: ${dnsRes.nsname} | Hostmaster: ${dnsRes.hostmaster} | Serial: ${dnsRes.serial} | Refresh: ${dnsRes.refresh} | Retry: ${dnsRes.retry} | Expire: ${dnsRes.expire} | MinTTL: ${dnsRes.minttl}`;
+                conditionsResult = handleConditions({ record: dnsRes.nsname });
+                break;
+
+            case "SRV":
+                dnsMessage = dnsRes.map(record => `Name: ${record.name} | Port: ${record.port} | Priority: ${record.priority} | Weight: ${record.weight}`).join(" | ");
+                conditionsResult = dnsRes.some(record => handleConditions({ record: record.name }));
+                break;
         }
 
         if (monitor.dns_last_result !== dnsMessage && dnsMessage !== undefined) {
@@ -46,7 +76,7 @@ class DnsMonitorType extends MonitorType {
         }
 
         heartbeat.msg = dnsMessage;
-        heartbeat.status = UP;
+        heartbeat.status = conditionsResult ? UP : DOWN;
     }
 }
 

server/monitor-types/monitor-type.js

@@ -1,6 +1,19 @@
 class MonitorType {
     name = undefined;
 
+    /**
+     * Whether or not this type supports monitor conditions. Controls UI visibility in monitor form.
+     * @type {boolean}
+     */
+    supportsConditions = false;
+
+    /**
+     * Variables supported by this type. e.g. an HTTP type could have a "response_code" variable to test against.
+     * This property controls the choices displayed in the monitor edit form.
+     * @type {import("../monitor-conditions/variables").ConditionVariable[]}
+     */
+    conditionVariables = [];
+
     /**
      * Run the monitoring check on the given monitor
      * @param {Monitor} monitor Monitor to check

server/server.js

@@ -132,7 +132,7 @@ const twoFAVerifyOptions = {
 const testMode = !!args["test"] || false;
 
 // Must be after io instantiation
-const { sendNotificationList, sendHeartbeatList, sendInfo, sendProxyList, sendDockerHostList, sendAPIKeyList, sendRemoteBrowserList } = require("./client");
+const { sendNotificationList, sendHeartbeatList, sendInfo, sendProxyList, sendDockerHostList, sendAPIKeyList, sendRemoteBrowserList, sendMonitorTypeList } = require("./client");
 const { statusPageSocketHandler } = require("./socket-handlers/status-page-socket-handler");
 const { databaseSocketHandler } = require("./socket-handlers/database-socket-handler");
 const { remoteBrowserSocketHandler } = require("./socket-handlers/remote-browser-socket-handler");
@@ -716,6 +716,8 @@ let needSetup = false;
                 monitor.kafkaProducerBrokers = JSON.stringify(monitor.kafkaProducerBrokers);
                 monitor.kafkaProducerSaslOptions = JSON.stringify(monitor.kafkaProducerSaslOptions);
 
+                monitor.conditions = JSON.stringify(monitor.conditions);
+
                 bean.import(monitor);
                 bean.user_id = socket.userID;
 
@@ -866,6 +868,7 @@ let needSetup = false;
                 bean.snmpOid = monitor.snmpOid;
                 bean.jsonPathOperator = monitor.jsonPathOperator;
                 bean.timeout = monitor.timeout;
+                bean.conditions = JSON.stringify(monitor.conditions);
 
                 bean.validate();
 
@@ -1671,6 +1674,7 @@ async function afterLogin(socket, user) {
         sendDockerHostList(socket),
         sendAPIKeyList(socket),
         sendRemoteBrowserList(socket),
+        sendMonitorTypeList(socket),
     ]);
 
     await StatusPage.sendStatusPageList(io, socket);