Update query project when switching datasources (#41)

Adds checks that the configured query projectName matches the current datasource instance projectName configuration. This resolves two current issues:

1. Switching between instances of the plugin when editing a query currently fails to update the query's project name to match.
2. Using a template variable for the query datasource currently fails to update the query's project name to match.

src/components/QueryEditor.tsx

@@ -18,6 +18,21 @@ export class QueryEditor extends PureComponent<Props, State> {
     isOptionsOpen: false,
   };
 
+  componentDidMount(): void {
+    const { query, datasource, onChange, onRunQuery } = this.props;
+    const projects = datasource.projects();
+
+    // onMount the editor must validate the configured query projectName is part
+    // of the configured datasource's configured projects
+    // nb: This is a required check for users with multiple instances of the
+    // plugin installed, switching between them needs to also update the query
+    // project name value
+    if (!projects.includes(query.projectName)) {
+      onChange({ ...query, projectName: datasource.defaultProjectName() });
+      onRunQuery();
+    }
+  }
+
   onQueryChange = (value: string) => {
     const { onChange, query } = this.props;
 

src/datasource.ts

@@ -37,10 +37,13 @@ export class DataSource extends DataSourceApi<LightstepQuery, LightstepDataSourc
   async query(request: DataQueryRequest<LightstepQuery>): Promise<DataQueryResponse> {
     try {
       const hashedEmail = await hashEmail(config.bootData.user.email);
+      const projects = this.projects();
 
-      // All queries _should_ have a project name, this decoration _ensures_ it
+      // Project name check: Ensure that every query has a projectName defined, and that
+      // the defined value is in the current datasource's configured set of projects.
+      // nb: This is a required check when users have setup a datasource template variable
       request.targets.forEach((target) => {
-        if (!target.projectName) {
+        if (!projects.includes(target.projectName)) {
           target.projectName = this.defaultProjectName();
         }
       });