Add set config for "apigeesync_apid_instance_id"

README.md

diff --git a/README.md b/README.md
index dc5ce38..bfd1612 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,12 @@
 | apigeesync_consumer_key      | string. required.        |
 | apigeesync_consumer_secret   | string. required.        |
 
+This plugin also populates a configuration item for dependant plugins that may need it:
+
+| name                         | description              |
+|------------------------------|--------------------------|
+| apigeesync_apid_instance_id  | string                   |
+
 ### Event Generated
 
 * Selector: "ApigeeSync"
@@ -33,10 +39,6 @@
     7. Release old DB version
     8. Start processing change events
 
-ToDo: ApigeeSync currently only receives a new snapshot during startup, so step #4 only happens once. However, it
- will eventually receive snapshots over time and the sub-steps should be followed at that time. Plugins 
- depending on ApigeeSync for data should assume that it can happen at any time and follow the heuristic below.
-
 #### ApigeeSync-dependent plugins
 1. Initialization
     1. Until receiving first Snapshot message, ApigeeSync-dependent APIs must either:

init.go

diff --git a/init.go b/init.go
index ff19bed..7eda269 100644
--- a/init.go
+++ b/init.go
@@ -18,6 +18,9 @@
 	configSnapshotProtocol    = "apigeesync_snapshot_proto"
 	configName                = "apigeesync_instance_name"
 	ApigeeSyncEventSelector   = "ApigeeSync"
+
+	// special value - set by ApigeeSync, not taken from configuration
+	configApidInstanceID      = "apigeesync_apid_instance_id"
 )
 
 var (
@@ -85,19 +88,24 @@
 	// set up default database
 	db, err := data.DB()
 	if err != nil {
-		log.Panicf("Unable to access DB: %v", err)
+		return pluginData, fmt.Errorf("Unable to access DB: %v", err)
 	}
 	err = initDB(db)
 	if err != nil {
-		log.Panicf("Unable to initialize DB: %v", err)
+		return pluginData, fmt.Errorf("Unable to access DB: %v", err)
 	}
 	setDB(db)
 
 	apidInfo, err = getApidInstanceInfo()
 	if err != nil {
-		log.Panicf("Unable to get apid instance info: %v", err)
+		return pluginData, fmt.Errorf("Unable to get apid instance info: %v", err)
 	}
 
+	if config.IsSet(configApidInstanceID) {
+		log.Warnf("ApigeeSync plugin overriding %s.", configApidInstanceID)
+	}
+	config.Set(configApidInstanceID, apidInfo.InstanceID)
+
 	log.Debug("end init")
 
 	return pluginData, nil

init_test.go

diff --git a/init_test.go b/init_test.go
index 6ff98c2..505502c 100644
--- a/init_test.go
+++ b/init_test.go
@@ -9,10 +9,11 @@
 
 	Context("Apid Instance display name", func() {
 
-		It("should be hostname by defauls", func() {
+		It("should be hostname by default", func() {
 			initDefaults()
 			Expect(apidInfo.InstanceName).To(Equal("testhost"))
 		})
+
 		It("accept display name from config", func() {
 			config.Set(configName, "aa01")
 			initDefaults()
@@ -22,4 +23,10 @@
 		})
 
 	})
+
+	It("should put apigeesync_apid_instance_id value in config", func() {
+		instanceID := config.GetString(configApidInstanceID)
+		Expect(instanceID).NotTo(BeEmpty())
+		Expect(instanceID).To(Equal(apidInfo.InstanceID))
+	})
 })