add client side pagination to lazily fetch pages

Author: tzzh

aws/aws.go

@@ -22,6 +22,7 @@ type Namespace struct {
 
 type Var struct {
 	Name string "name"
+	Code string `bencode:"code,omitempty"`
 }
 
 type DescribeResponse struct {

babashka/babashka.go

@@ -165,12 +165,24 @@
     (str prefix-fn-name "Output")
     (str aws-fn-name "Output")))
 
+(def quoted-get-paginator
+  (quote
+    (defn get-paginator
+      "Returns a fn that lazily fetches the pages for a given aws fn"
+      [page-fn]
+      (fn get-pages
+        [input]
+        (lazy-seq
+          (let [page (page-fn input)]
+            (if-let [next-continuation-token (:NextContinuationToken page)]
+              (cons page (get-pages (assoc input :ContinuationToken next-continuation-token)))
+              [page])))))))
+
 (def t
   "
 // Code generated by generate.clj DO NOT EDIT
 package aws
 
-
 import (
 \"encoding/json\"
 \"github.com/aws/aws-sdk-go/aws/session\"
@@ -186,6 +198,12 @@ if message.Op == \"describe\" {
     response := &babashka.DescribeResponse{
         Format: \"json\",
         Namespaces: []babashka.Namespace{
+            {Name: \"pod.tzzh.paginator\",
+             Vars: []babashka.Var{
+                {Name: \"get-paginator\",
+                 Code: `<%= paginator %>`},
+                },
+             },
         <% (doseq [[ns-name ns-fns] namespaces]
           %>{Name: \"pod.tzzh.<%= ns-name %>\",
             Vars: []babashka.Var{
@@ -236,7 +254,8 @@ if message.Op == \"describe\" {
 
 (when (= *file* (System/getProperty "babashka.file"))
   (let [aws-go "./aws/aws.go"]
-    (spit aws-go (template/eval t {:namespaces aws-api}))
+    (spit aws-go (template/eval t {:namespaces aws-api
+                                   :paginator (str quoted-get-paginator)}))
     (let [{:keys [err exit]} (shell/sh "go" "fmt" aws-go)]
       (when-not (empty? err)
         (print err))