From 791584d9f3381ca62d7a20aff0e4220a6e356d9f Mon Sep 17 00:00:00 2001
From: Michael Bridgen <mikeb@squaremobius.net>
Date: Tue, 2 Jun 2015 17:31:25 +0100
Subject: [PATCH] Allow lookup of IPAM-allocated addresses

---
 ipam/allocator.go | 14 ++++++++++++++
 ipam/http.go      |  9 +++++++++
 ipam/http_test.go | 15 ++++++++++++++-
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/ipam/allocator.go b/ipam/allocator.go
index 62017db6..b6260b50 100644
--- a/ipam/allocator.go
+++ b/ipam/allocator.go
@@ -208,6 +208,20 @@ func (alloc *Allocator) Allocate(ident string, cancelChan <-chan bool) (address.
 	return result.addr, result.err
 }
 
+func (alloc *Allocator) Lookup(ident string) (address.Address, error) {
+	resultChan := make(chan allocateResult)
+	alloc.actionChan <- func() {
+		addr, found := alloc.owned[ident]
+		if found {
+			resultChan <- allocateResult{addr: addr}
+			return
+		}
+		resultChan <- allocateResult{err: fmt.Errorf("lookup: no address found")}
+	}
+	result := <-resultChan
+	return result.addr, result.err
+}
+
 // Claim an address that we think we should own (Sync)
 func (alloc *Allocator) Claim(ident string, addr address.Address, cancelChan <-chan bool) error {
 	resultChan := make(chan error)
diff --git a/ipam/http.go b/ipam/http.go
index c7778996..4e7cd907 100644
--- a/ipam/http.go
+++ b/ipam/http.go
@@ -33,6 +33,15 @@ func (alloc *Allocator) HandleHTTP(router *mux.Router) {
 		w.WriteHeader(204)
 	})
 
+	router.Methods("GET").Path("/ip/{id}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		addr, err := alloc.Lookup(mux.Vars(r)["id"])
+		if err != nil {
+			http.NotFound(w, r)
+			return
+		}
+		fmt.Fprintf(w, "%s/%d", addr.String(), alloc.prefixLen)
+	})
+
 	router.Methods("POST").Path("/ip/{id}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		closedChan := w.(http.CloseNotifier).CloseNotify()
 		ident := mux.Vars(r)["id"]
diff --git a/ipam/http_test.go b/ipam/http_test.go
index b8c972f0..f1a828d1 100644
--- a/ipam/http_test.go
+++ b/ipam/http_test.go
@@ -25,6 +25,14 @@ func HTTPPost(t *testing.T, url string) string {
 	return string(body)
 }
 
+func HTTPGet(t *testing.T, url string) string {
+	resp, err := http.Get(url)
+	wt.AssertNoErr(t, err)
+	defer resp.Body.Close()
+	body, _ := ioutil.ReadAll(resp.Body)
+	return string(body)
+}
+
 func doHTTP(method string, url string) (resp *http.Response, err error) {
 	req, _ := http.NewRequest(method, url, nil)
 	return http.DefaultClient.Do(req)
@@ -72,6 +80,8 @@ func TestHttp(t *testing.T) {
 	// Ask the http server for a new address
 	cidr1 := HTTPPost(t, allocURL(port, containerID))
 	wt.AssertEqualString(t, cidr1, testAddr1+netSuffix, "address")
+	check := HTTPGet(t, allocURL(port, containerID))
+	wt.AssertEqualString(t, check, cidr1, "address")
 
 	// Ask the http server for another address and check it's different
 	cidr2 := HTTPPost(t, allocURL(port, container2))
@@ -80,9 +90,12 @@ func TestHttp(t *testing.T) {
 	// Ask for the first container again and we should get the same address again
 	cidr1a := HTTPPost(t, allocURL(port, containerID))
 	wt.AssertEqualString(t, cidr1a, testAddr1+netSuffix, "address")
-
 	// Now free the first one, and we should get it back when we ask
 	doHTTP("DELETE", allocURL(port, containerID))
+	resp, err := doHTTP("GET", allocURL(port, containerID))
+	wt.AssertNoErr(t, err)
+	wt.AssertStatus(t, resp.StatusCode, http.StatusNotFound, "http response")
+
 	cidr3 := HTTPPost(t, allocURL(port, container3))
 	wt.AssertEqualString(t, cidr3, testAddr1+netSuffix, "address")