Skip mounting services on incompatible versions

This commit adds guard logic to the Clojure FactsUploadService that ensures
routes and status info are not mounted if the plug-in is loaded by an
incompatible Puppet Server version. Compatibility is currently defined by
the X.Y components of the version number and restricted to Puppet Server
5.1 and 5.2.

A test against Puppet Server 5.3 is added to ensure the noop behavior is
triggered.

Ref. issue #2.

.travis.yml

@@ -14,12 +14,15 @@ matrix:
     - jdk: openjdk8
       script: 'bundle exec rake test:integration'
       env: PUPPETSERVER_VERSION=5.1.5
+    - jdk: oraclejdk8
+      script: 'bundle exec rake test:integration'
+      env: PUPPETSERVER_VERSION=5.1.5
     - jdk: openjdk8
       script: 'bundle exec rake test:integration'
       env: PUPPETSERVER_VERSION=5.2.0
-    - jdk: oraclejdk8
+    - jdk: openjdk8
       script: 'bundle exec rake test:integration'
-      env: PUPPETSERVER_VERSION=5.1.5
+      env: PUPPETSERVER_VERSION=5.3.0
 
     - jdk: openjdk8
       sudo: required

CHANGELOG.md

@@ -6,7 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+### Fixed
 
+  - The `facts_upload.jar` plugin will no longer activate when loaded by
+    a Puppet Server version that the plugin is not compatible with.
 
 ## [1.0.2] - 2018-02-21
 ### Added

src/clj/puppetlabs/services/facts_upload/facts_upload_service.clj

@@ -1,5 +1,7 @@
 (ns puppetlabs.services.facts-upload.facts-upload-service
   (:require
+   [clojure.edn :as edn]
+   [clojure.string :as string]
    [clojure.tools.logging :as log]
    [puppetlabs.services.facts-upload.facts-upload-core :as core]
    [puppetlabs.trapperkeeper.core :refer [defservice]]
@@ -8,11 +10,37 @@
 
 
 (def version
-  "The service version, from project.clj"
+  "The facts_upload module version, from project.clj"
   (status-core/get-artifact-version "sharpie" "facts-upload"))
 
+(def puppetserver-version
+  "Retrieve Puppet Server version in use.
+
+  This function retrieves just the X and Y components of the version
+  and casts them to a floating point number that can be compared."
+  (try
+    (as-> (status-core/get-artifact-version "puppetlabs" "puppetserver") x
+          (string/split x #"\.")
+          (take 2 x)
+          (string/join "." x)
+          (edn/read-string x))
+    (catch Exception e
+      (log/errorf "Couldn't determine Puppet Server version %s" e)
+      nil)))
+
 (defprotocol FactsUploadService)
 
+
+(defn compatible-puppetserver-version?
+  "Determine whether Puppet Server is compatible with facts_upload.
+
+  This function returns a simple boolean value."
+  []
+  (if (nil? puppetserver-version)
+    false
+    (and (>= puppetserver-version 5.1)
+         (< puppetserver-version 5.3))))
+
 (defservice facts-upload-service
   FactsUploadService
   [[:StatusService register-status]
@@ -26,27 +54,33 @@
   (init [this context]
     ;; TODO: Only build the handler if we detect a compatible version of
     ;; Puppet Server.
-    (log/info "Initializing FileServing service")
-    (let [puppet-config (get-config)
-          auth-handler (get-auth-handler)
-          jruby-service (services/get-service this :JRubyPuppetService)
-          jruby-handler (core/create-wrapped-jruby-handler puppet-config
-                                                           current-code-id
-                                                           jruby-service
-                                                           auth-handler)
-          facts-handler (core/create-request-handler jruby-handler)]
+    (if (compatible-puppetserver-version?)
+      (do
+        (log/info "Initializing FactsUpload service")
+        (let [puppet-config (get-config)
+              auth-handler (get-auth-handler)
+              jruby-service (services/get-service this :JRubyPuppetService)
+              jruby-handler (core/create-wrapped-jruby-handler puppet-config
+                                                               current-code-id
+                                                               jruby-service
+                                                               auth-handler)
+              facts-handler (core/create-request-handler jruby-handler)]
 
-      (register-status "facts-upload-service" version 1
-                       (core/create-status-callback context))
+          (register-status "facts-upload-service" version 1
+                           (core/create-status-callback context))
 
-      (assoc context :request-handler facts-handler)))
+          (assoc context :request-handler facts-handler)))
+      (do
+        (log/errorf "The facts_upload module is not compatible with Puppet Server %s and should be removed from this node."
+                    puppetserver-version)
+        context)))
 
 
   (start [this context]
     ;; FIXME: Use the WebroutingService to lookup which path the MasterService
     ;; is mounted at.
     (when-let [handler (:request-handler context)]
-      (log/info "Starting FactsUploadService")
+      (log/info "Starting FactsUpload service")
       (add-ring-handler handler "/puppet/v3/facts"))
 
     context))

test/integration/puppetlabs/services/facts_upload/facts_upload_service_test.clj

@@ -27,10 +27,6 @@
 
 ;; Test Configuration
 
-(def puppetserver-version
-  "Version of Puppet Server that we are currently running against."
-  (status-core/get-artifact-version "puppetlabs" "puppetserver"))
-
 (defn test-resource
   "Locates a path within the registered Java resource directories and returns
   a fully qualified path"
@@ -98,7 +94,7 @@
 
 
 (deftest ^:integration facts-upload-service
-  (printf "Testing against Puppet Server version: %s%n" puppetserver-version)
+  (printf "Testing against Puppet Server version: %s%n" facts-upload/puppetserver-version)
 
   (tst-bootstrap/with-app-with-config app app-services base-config
     (let [jruby-service (tk-app/get-service app :JRubyPuppetService)
@@ -124,8 +120,15 @@
         (finally
           (jruby-testutils/return-instance jruby-service jruby-instance :facts-upload-endpoint-test)))
 
-      (testing "facts-upload plugin version number is available via status service"
+      (testing "facts-upload plugin is enabled appropriately"
         (let [response (GET "/status/v1/services?level=debug")
-              body (-> response :body json/parse-string)]
+              body (-> response :body json/parse-string)
+              ;; When run against an incompatible Puppet Server version, we
+              ;; expect the TK status service to return a response that does
+              ;; not reference the facts-upload service, i.e. nil, which
+              ;; indicates the service was not mounted.
+              expected-version (if (facts-upload/compatible-puppetserver-version?)
+                                   facts-upload/version
+                                   nil)]
           (is (= 200 (:status response)))
-          (is (= facts-upload/version (get-in body ["facts-upload-service" "service_version"]))))))))
+          (is (= expected-version (get-in body ["facts-upload-service" "service_version"]))))))))