Add 'GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR' to allow plugins to fail a build

Makefile

@@ -13,10 +13,12 @@ OPEN_RESOURCE=bash -c 'open $$0 || xdg-open $$0'
 SLIDESHOW_TO_PDF?=bash -c 'docker run --rm -v `pwd`:/cwd astefanutti/decktape /cwd/$$0 /cwd/`dirname $$0`/`basename -s .html $$0`.pdf'
 YARN := $(shell $(IN_VENV) command -v yarn 2> /dev/null)
 YARN_INSTALL_OPTS=--network-timeout 300000 --check-files
+# Default to not fail on error, set to 1 to fail client builds on a plugin error.
+GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR?=0
 # Respect predefined NODE_OPTIONS, otherwise set maximum heap size low for
 # compatibility with smaller machines.
 NODE_OPTIONS ?= --max-old-space-size=3072
-NODE_ENV = env NODE_OPTIONS=$(NODE_OPTIONS)
+NODE_ENV = env NODE_OPTIONS=$(NODE_OPTIONS) GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR=$(GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR)	
 CWL_TARGETS := test/functional/tools/cwl_tools/v1.0/conformance_tests.yaml \
 	test/functional/tools/cwl_tools/v1.1/conformance_tests.yaml \
 	test/functional/tools/cwl_tools/v1.2/conformance_tests.yaml \

client/gulpfile.js

@@ -56,6 +56,11 @@ const PATHS = {
     },
 };
 
+const failOnError =
+    process.env.GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR && process.env.GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR !== "0"
+        ? true
+        : false;
+
 PATHS.pluginBaseDir =
     (process.env.GALAXY_PLUGIN_PATH && process.env.GALAXY_PLUGIN_PATH !== "None"
         ? process.env.GALAXY_PLUGIN_PATH
@@ -186,6 +191,13 @@ function buildPlugins(callback, forceRebuild) {
                 console.error(
                     `Error building ${pluginName}, not saving build state.  Please report this issue to the Galaxy Team.`
                 );
+                if (failOnError) {
+                    // Fail on error.
+                    console.error(
+                        "Failing build due to GALAXY_PLUGIN_BUILD_FAIL_ON_ERROR being set, see error(s) above."
+                    );
+                    process.exit(1);
+                }
             }
         }
     });