variable support for interpreter

src/plugins/expressions/public/execute.ts

@@ -65,6 +65,7 @@ export class ExpressionDataHandler {
         getInitialContext,
         inspectorAdapters: this.inspectorAdapters,
         abortSignal: this.abortController.signal,
+        variables: params.variables,
       })
       .then(
         (v: IInterpreterResult) => {

src/plugins/expressions/public/functions/tests/var.test.ts

@@ -0,0 +1,63 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { functionWrapper } from './utils';
+import { variable } from '../var';
+import { FunctionHandlers } from '../../../common/types';
+import { KibanaContext } from '../../../common/expression_types/kibana_context';
+
+describe('interpreter/functions#var', () => {
+  const fn = functionWrapper(variable);
+  let context: Partial<KibanaContext>;
+  let initialContext: KibanaContext;
+  let handlers: FunctionHandlers;
+
+  beforeEach(() => {
+    context = { timeRange: { from: '0', to: '1' } };
+    initialContext = {
+      type: 'kibana_context',
+      query: { language: 'lucene', query: 'geo.src:US' },
+      filters: [
+        {
+          meta: {
+            disabled: false,
+            negate: false,
+            alias: null,
+          },
+          query: { match: {} },
+        },
+      ],
+      timeRange: { from: '2', to: '3' },
+    };
+    handlers = {
+      getInitialContext: () => initialContext,
+      variables: { test: 1 } as any,
+    };
+  });
+
+  it('returns the selected variable', () => {
+    const actual = fn(context, { name: 'test' }, handlers);
+    expect(actual).toEqual(1);
+  });
+
+  it('returns undefined if variable does not exist', () => {
+    const actual = fn(context, { name: 'unknown' }, handlers);
+    expect(actual).toEqual(undefined);
+  });
+});

src/plugins/expressions/public/functions/tests/var_set.test.ts

@@ -0,0 +1,74 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { functionWrapper } from './utils';
+import { variableSet } from '../var_set';
+import { FunctionHandlers } from '../../../common/types';
+import { KibanaContext } from '../../../common/expression_types/kibana_context';
+
+describe('interpreter/functions#varset', () => {
+  const fn = functionWrapper(variableSet);
+  let context: Partial<KibanaContext>;
+  let initialContext: KibanaContext;
+  let handlers: FunctionHandlers;
+  let variables: Record<string, any>;
+
+  beforeEach(() => {
+    context = { timeRange: { from: '0', to: '1' } };
+    initialContext = {
+      type: 'kibana_context',
+      query: { language: 'lucene', query: 'geo.src:US' },
+      filters: [
+        {
+          meta: {
+            disabled: false,
+            negate: false,
+            alias: null,
+          },
+          query: { match: {} },
+        },
+      ],
+      timeRange: { from: '2', to: '3' },
+    };
+    handlers = {
+      getInitialContext: () => initialContext,
+      variables: { test: 1 } as any,
+    };
+
+    variables = handlers.variables;
+  });
+
+  it('updates a variable', () => {
+    const actual = fn(context, { name: 'test', value: 2 }, handlers);
+    expect(variables.test).toEqual(2);
+    expect(actual).toEqual(context);
+  });
+
+  it('sets a new variable', () => {
+    const actual = fn(context, { name: 'new', value: 3 }, handlers);
+    expect(variables.new).toEqual(3);
+    expect(actual).toEqual(context);
+  });
+
+  it('stores context if value is not set', () => {
+    const actual = fn(context, { name: 'test' }, handlers);
+    expect(variables.test).toEqual(context);
+    expect(actual).toEqual(context);
+  });
+});

src/plugins/expressions/public/functions/var.ts

@@ -0,0 +1,49 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { i18n } from '@kbn/i18n';
+import { ExpressionFunction } from '../../common/types';
+
+interface Arguments {
+  name: string;
+}
+
+type Context = any;
+type ExpressionFunctionVar = ExpressionFunction<'var', Context, Arguments, any>;
+
+export const variable = (): ExpressionFunctionVar => ({
+  name: 'var',
+  help: i18n.translate('expressions.functions.var.help', {
+    defaultMessage: 'Updates kibana global context',
+  }),
+  args: {
+    name: {
+      types: ['string'],
+      aliases: ['_'],
+      required: true,
+      help: i18n.translate('expressions.functions.var.name.help', {
+        defaultMessage: 'Specify name of the variable',
+      }),
+    },
+  },
+  fn(context, args, handlers) {
+    const variables: Record<string, any> = handlers.variables;
+    return variables[args.name];
+  },
+});

src/plugins/expressions/public/functions/var_set.ts

@@ -0,0 +1,58 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { i18n } from '@kbn/i18n';
+import { ExpressionFunction } from '../../common/types';
+
+interface Arguments {
+  name: string;
+  value?: any;
+}
+
+type Context = any;
+type ExpressionFunctionVarSet = ExpressionFunction<'var_set', Context, Arguments, Context>;
+
+export const variableSet = (): ExpressionFunctionVarSet => ({
+  name: 'var_set',
+  help: i18n.translate('expressions.functions.varset.help', {
+    defaultMessage: 'Updates kibana global context',
+  }),
+  args: {
+    name: {
+      types: ['string'],
+      aliases: ['_'],
+      required: true,
+      help: i18n.translate('expressions.functions.varset.name.help', {
+        defaultMessage: 'Specify name of the variable',
+      }),
+    },
+    value: {
+      aliases: ['val'],
+      help: i18n.translate('expressions.functions.varset.val.help', {
+        defaultMessage:
+          'Specify value for the variable. If not provided input context will be used',
+      }),
+    },
+  },
+  fn(context, args, handlers) {
+    const variables: Record<string, any> = handlers.variables;
+    variables[args.name] = args.value === undefined ? context : args.value;
+    return context;
+  },
+});

src/plugins/expressions/public/loader.ts

@@ -178,6 +178,9 @@ export class ExpressionLoader {
     if (params.extraHandlers && this.params) {
       this.params.extraHandlers = params.extraHandlers;
     }
+    if (params.variables && this.params) {
+      this.params.variables = params.variables;
+    }
   }
 }
 

src/plugins/expressions/public/plugin.ts

@@ -32,6 +32,8 @@ import { clog as clogFunction } from './functions/clog';
 import { font as fontFunction } from './functions/font';
 import { kibana as kibanaFunction } from './functions/kibana';
 import { kibanaContext as kibanaContextFunction } from './functions/kibana_context';
+import { variable } from './functions/var';
+import { variableSet } from './functions/var_set';
 import {
   boolean as booleanType,
   datatable as datatableType,
@@ -109,6 +111,8 @@ export class ExpressionsPublicPlugin
     registerFunction(fontFunction);
     registerFunction(kibanaFunction);
     registerFunction(kibanaContextFunction);
+    registerFunction(variable);
+    registerFunction(variableSet);
 
     types.register(booleanType);
     types.register(datatableType);

src/plugins/expressions/public/types/index.ts

@@ -65,6 +65,7 @@ export interface IExpressionLoaderParams {
 export interface IInterpreterHandlers {
   getInitialContext: IGetInitialContext;
   inspectorAdapters?: Adapters;
+  variables?: Record<string, any>;
   abortSignal?: AbortSignal;
 }