From 68e13e0aec50a12b343aec8c2009162e4dbc08de Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Wed, 28 Nov 2018 12:44:54 -0500
Subject: First working version.

---
 aws/cloudformation/utils.scm | 277 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 277 insertions(+)
 create mode 100644 aws/cloudformation/utils.scm

(limited to 'aws/cloudformation/utils.scm')

diff --git a/aws/cloudformation/utils.scm b/aws/cloudformation/utils.scm
new file mode 100644
index 0000000..e618cf8
--- /dev/null
+++ b/aws/cloudformation/utils.scm
@@ -0,0 +1,277 @@
+(define-module (aws cloudformation utils)
+  #:use-module (aws cloudformation utils base32)
+  #:use-module (aws cloudformation utils sha-1)
+  #:use-module (ice-9 match)
+  #:use-module (oop goops)
+  #:use-module (rnrs bytevectors)
+  #:use-module (srfi srfi-1)
+  #:export (<cloudformation-property>
+            <cloudformation-object>
+            <cloudformation-attribute>
+            <cloudformation-resource>
+            <cloudformation-stack>
+            attributes
+            aws-string->symbol
+            description
+            documentation-url
+            id
+            name
+            outputs
+            parameters
+            primitive-type
+            properties
+            required?
+            resource-name
+            resources
+            to-json
+            type-check
+            type-checker
+            update-type
+            valid?))
+
+(define (aws-string->symbol str)
+  ;; Drop the "AWS::" that's at the beginning of *almost* everything.
+  (let ((str (if (string-prefix? "AWS::" str)
+                 (string-drop str 5)
+                 str)))
+    (list->symbol
+     (let loop ((i 0)
+                (same-word? #t)
+                (slash-delimiter? #f))
+       (cond
+        ((= i (string-length str)) ; end of string
+         '())
+        ;; "IoT" violates all the rules. grrrr
+        ((and (< (+ i 3) (string-length str))
+              (eqv? (string-ref str i) #\I)
+              (eqv? (string-ref str (+ i 1)) #\o)
+              (eqv? (string-ref str (+ i 2)) #\T))
+         (cons* #\i #\o #\t (loop (+ i 3) #f #f)))
+        ;; Replace "." with "/"
+        ((eqv? (string-ref str i) #\.)
+         (cons #\/ (loop (1+ i) #f #t)))
+        ;; Get rid of "::"
+        ((and (eqv? (string-ref str i) #\:)
+              (eqv? (string-ref str (1+ i)) #\:))
+         (loop (+ i 2) #f #f))
+        ((char-upper-case? (string-ref str i)) ; detect camel casing
+         (cond
+          ;; If we've had a string of uppercase characters and the
+          ;; next character is lowercase, we're actually at the
+          ;; beginning of a new word.  For example, when we reach the
+          ;; "I" in "DBInstance" we need to treat it as the beginning
+          ;; of a new word.
+          ((and same-word?
+                (< (1+ i) (string-length str))
+                (char-lower-case? (string-ref str (1+ i))))
+           (loop i #f #f))
+          ;; Consecutive uppercase characters are part of the same word.
+          (same-word?
+           (cons (char-downcase (string-ref str i)) (loop (1+ i) #t #f)))
+          ;; Encountering an uppercase character after a series of
+          ;; non-uppercase characters means that we are at the
+          ;; beginning of a new word.
+          (else
+           (if (or (zero? i) slash-delimiter?)
+               (cons (char-downcase (string-ref str i)) (loop (1+ i) #t #f))
+               (cons* #\- (char-downcase (string-ref str i))
+                      (loop (1+ i) #t #f))))))
+        (else
+         (cons (string-ref str i) (loop (1+ i) #f #f))))))))
+
+(define-class <cloudformation-property> ()
+  (name #:getter name #:init-keyword #:name)
+  (type-checker #:getter type-checker #:init-keyword #:type-checker)
+  (required? #:getter required? #:init-keyword #:required?)
+  (update-type #:getter update-type #:init-keyword #:update-type)
+  (documentation-url #:getter documentation-url
+                     #:init-keyword #:documentation-url))
+
+(define-method (type-check (procedure <procedure>) x)
+  (procedure x))
+
+(define-method (type-check (property <cloudformation-property>) x)
+  ((type-checker property) x))
+
+(define-class <cloudformation-class> (<class>)
+  (properties #:getter properties)
+  (cfn-name #:getter cfn-name)
+  (documentation-url #:getter documentation-url))
+
+(define-method (initialize (cfn-class <cloudformation-class>) args)
+  (define* (slot-cfn-property slot-name #:key cfn-property #:allow-other-keys)
+    (and cfn-property (cons slot-name cfn-property)))
+  (define* (init #:key cfn-name documentation-url slots #:allow-other-keys)
+    (slot-set! cfn-class 'cfn-name cfn-name)
+    (slot-set! cfn-class 'documentation-url documentation-url)
+    (slot-set! cfn-class
+               'properties
+               (filter-map (lambda (slot-args)
+                             (apply slot-cfn-property slot-args))
+                           slots)))
+  (apply init args)
+  (next-method))
+
+(define-class <cloudformation-object> ()
+  #:metaclass <cloudformation-class>)
+
+(define-method (initialize (obj <cloudformation-object>) args)
+  (next-method)
+  ;; Ensure that all required properties have been specified, and that
+  ;; all specified properties pass the type checker.
+  (for-each (match-lambda
+              ((slot-name . prop)
+               (cond
+                ((and (required? prop) (not (slot-bound? obj slot-name)))
+                 (error "required property not specified:" slot-name))
+                ((slot-bound? obj slot-name)
+                 (let ((value (slot-ref obj slot-name)))
+                   (unless (type-check prop value)
+                     (error "wrong type for property:" slot-name value)))))))
+            (slot-ref (class-of obj) 'properties)))
+
+(define-method (cfn-name (obj <cloudformation-object>))
+  (cfn-name (class-of obj)))
+
+(define-method (properties (obj <cloudformation-object>))
+  (slot-ref (class-of obj) 'properties))
+
+(define-method (to-json/refs obj)
+  (to-json obj))
+
+(define-method (to-json (s <string>)) s)
+(define-method (to-json (b <boolean>)) b)
+(define-method (to-json (n <number>)) n)
+(define-method (to-json (p <pair>))
+  (if (pair? (car p))
+      `(@ ,@(map (match-lambda
+                   ((k . v)
+                    (cons k (to-json/refs v))))
+                 p))
+      (cons (to-json/refs (car p)) (to-json (cdr p)))))
+(define-method (to-json (null <null>))
+  '())
+
+(define-method (to-json (obj <cloudformation-object>))
+  (cons '@
+   (filter-map (match-lambda
+                 ((slot-name . property)
+                  (and (slot-bound? obj slot-name)
+                       (cons (name property)
+                             (to-json/refs (slot-ref obj slot-name))))))
+               (properties obj))))
+
+(define-method (valid? (obj <cloudformation-object>))
+  (every (match-lambda
+           ((slot-name . property)
+            (cond
+             ((and (required? property) (not (slot-bound? obj slot-name)))
+              #f)
+             ((not (or (required? property) (slot-bound? obj slot-name)))
+              #t)
+             (else
+              (type-check property (slot-ref obj slot-name))))))
+         (slot-ref (class-of obj) 'properties)))
+
+(define-class <cloudformation-attribute> ()
+  (name #:getter name #:init-keyword #:name)
+  (primitive-type #:getter primitive-type #:init-keyword #:primitive-type))
+
+(define-class <cloudformation-resource-class> (<cloudformation-class>)
+  (resource-name-prefix #:getter resource-name-prefix)
+  (attributes #:getter attributes))
+
+(define-method (initialize (resource-class <cloudformation-resource-class>) args)
+  (define* (init #:key attributes cfn-name #:allow-other-keys)
+    (when cfn-name
+      (slot-set! resource-class 'resource-name-prefix
+                 (string-join (drop (delete "" (string-split cfn-name #\:)) 1)
+                              "")))
+    (slot-set! resource-class 'attributes attributes))
+  (apply init args)
+  (next-method))
+
+(define-class <cloudformation-resource> (<cloudformation-object>)
+  (id #:getter id #:init-keyword #:id)
+  (cfn-id #:getter cfn-id)
+  #:metaclass <cloudformation-resource-class>)
+
+(define char-set:alphanumeric
+  (char-set-intersection char-set:ascii char-set:letter+digit))
+
+(define (alphanumize s)
+  (string-filter char-set:alphanumeric s))
+
+(define (id->cfn-id sym)
+  (string-append (let ((camelized
+                        (string-concatenate
+                         (map (lambda (s)
+                                (string-capitalize (alphanumize s)))
+                              (string-split (symbol->string sym) #\-)))))
+                   (if (> (string-length camelized) 223)
+                       (substring camelized 223)
+                       camelized))
+                 (base32-encode
+                  (sha-1->bytevector
+                   (sha-1
+                    (string->utf8
+                     (symbol->string sym)))))))
+
+(define-method (initialize (resource <cloudformation-resource>) args)
+  (next-method)
+  (unless (slot-bound? resource 'id)
+    (error "no id specified for resource:" resource))
+  (slot-set! resource 'cfn-id (id->cfn-id (id resource))))
+
+(define-method (type-check (proc <procedure>)
+                           (resource <cloudformation-resource>))
+  (type-check proc "arn:dummy"))
+
+(define-method (to-json/refs (resource <cloudformation-resource>))
+  `(@ ("Ref" . ,(cfn-id resource))))
+
+(define-method (to-json (resource <cloudformation-resource>))
+  `(@ ("Type" . ,(cfn-name resource))
+      ("Properties" . ,(next-method))))
+
+(define-class <cloudformation-stack> ()
+  (description #:getter description #:init-keyword #:description #:init-form "")
+  (parameters #:getter parameters #:init-keyword #:parameters)
+  (resources #:getter resources #:init-keyword #:resources)
+  (outputs #:getter outputs #:init-keyword #:outputs))
+
+(define-method (transitive-resources (stack <cloudformation-stack>))
+  (define (scan-object obj)
+    (cond
+     ((is-a? obj <pair>)
+      (match obj
+        ((first rest ...)
+         (concatenate (cons (scan-object first)
+                            (scan-object rest))))
+        ((key . value)
+         (scan-object value))))
+     ((is-a? obj <cloudformation-resource>)
+      (list obj))
+     ((is-a? obj <cloudformation-object>)
+      (scan-properties obj))
+     (else
+      '())))
+  (define (scan-properties obj)
+    (append-map (match-lambda
+                  ((slot-name . prop)
+                   (let ((value (and (slot-bound? obj slot-name)
+                                     (slot-ref obj slot-name))))
+                     (scan-object value))))
+                (properties obj)))
+  (append-map (lambda (resource)
+                (cons resource (scan-properties resource)))
+              (resources stack)))
+
+(define-method (to-json (stack <cloudformation-stack>))
+  `(@ ("AWSTemplateFormatVersion" . "2010-09-09")
+      ("Description" . ,(description stack))
+      ("Resources" .
+       (@ ,@(map (lambda (resource)
+                   (cons (cfn-id resource)
+                         (to-json resource)))
+                 (transitive-resources stack))))))
-- 
cgit v1.2.3