[bug#52555] [RFC PATCH v2 2/5] publish: Add ERIS URN to narinfo

[pukkamustard]

* guix/scripts/publish.scm: (bake-narinfo+nar): Compute ERIS URN of compressed 
nars.
(narinfo-string): Add #:eris-urn parameter and honor it.
* guix/scripts/narinfo.scm: (<narinfo>)[eris-format,eris-urn]: New fields.
(narinfo-maker): Handle ERIS URN and ERIS format.
* configure.ac: (HAVE_GUILE_ERIS): New conditional.
* gnu/packages/package-management.scm: (guix)[native-inputs]: Add guile-eris.
---
 configure.ac                        |  5 +++++
 gnu/packages/package-management.scm |  1 +
 guix/narinfo.scm                    | 14 ++++++++++----
 guix/scripts/publish.scm            | 24 ++++++++++++++++++++----
 4 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index 341cff8fbd..72396be8aa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -170,6 +170,11 @@ GUILE_MODULE_AVAILABLE([have_guile_avahi], [(avahi)])
 AM_CONDITIONAL([HAVE_GUILE_AVAHI],
   [test "x$have_guile_avahi" = "xyes"])
 
+dnl Check for Guile-eris.
+GUILE_MODULE_AVAILABLE([have_guile_eris], [(eris)])
+AM_CONDITIONAL([HAVE_GUILE_ERIS],
+  [test "x$have_guile_eris" = "xyes"])
+
 dnl Guile-newt is used by the graphical installer.
 GUILE_MODULE_AVAILABLE([have_guile_newt], [(newt)])
 
diff --git a/gnu/packages/package-management.scm 
b/gnu/packages/package-management.scm
index 05795824b5..a9094b8b7f 100644
--- a/gnu/packages/package-management.scm
+++ b/gnu/packages/package-management.scm
@@ -404,6 +404,7 @@ (define code
                        ("guile-zstd" ,guile-zstd)
                        ("guile-ssh" ,guile-ssh)
                        ("guile-git" ,guile-git)
+                       ("guile-eris" ,guile-eris)
 
                        ;; XXX: Keep the development inputs here even though
                        ;; they're unnecessary, just so that 'guix environment
diff --git a/guix/narinfo.scm b/guix/narinfo.scm
index 4fc550aa6c..a6a5d3b84b 100644
--- a/guix/narinfo.scm
+++ b/guix/narinfo.scm
@@ -45,6 +45,8 @@ (define-module (guix narinfo)
             narinfo-file-sizes
             narinfo-hash
             narinfo-size
+            narinfo-eris-format
+            narinfo-eris-urn
             narinfo-references
             narinfo-deriver
             narinfo-system
@@ -68,8 +70,8 @@ (define-module (guix narinfo)
 
 (define-record-type <narinfo>
   (%make-narinfo path uri-base uris compressions file-sizes file-hashes
-                 nar-hash nar-size references deriver system
-                 signature contents)
+                 nar-hash nar-size eris-format eris-urn references deriver
+                 system signature contents)
   narinfo?
   (path         narinfo-path)
   (uri-base     narinfo-uri-base)        ;URI of the cache it originates from
@@ -79,6 +81,8 @@ (define-record-type <narinfo>
   (file-hashes  narinfo-file-hashes)
   (nar-hash     narinfo-hash)
   (nar-size     narinfo-size)
+  (eris-format  narinfo-eris-format)
+  (eris-urn     narinfo-eris-urn)
   (references   narinfo-references)
   (deriver      narinfo-deriver)
   (system       narinfo-system)
@@ -135,7 +139,7 @@ (define (narinfo-maker str cache-url)
   "Return a narinfo constructor for narinfos originating from CACHE-URL.  STR
 must contain the original contents of a narinfo file."
   (lambda (path urls compressions file-hashes file-sizes
-                nar-hash nar-size references deriver system
+                nar-hash nar-size eris-format eris-urn references deriver 
system
                 signature)
     "Return a new <narinfo> object."
     (define len (length urls))
@@ -157,6 +161,8 @@ (define len (length urls))
                      ((lst ...) (map string->number lst)))
                    nar-hash
                    (and=> nar-size string->number)
+                   eris-format
+                   (if eris-urn (string->uri eris-urn) #f)
                    (string-tokenize references)
                    (match deriver
                      ((or #f "") #f)
@@ -184,7 +190,7 @@ (define* (read-narinfo port #:optional url
                    (narinfo-maker str url)
                    '("StorePath" "URL" "Compression"
                      "FileHash" "FileSize" "NarHash" "NarSize"
-                     "References" "Deriver" "System"
+                     "ERISFormat" "ERIS" "References" "Deriver" "System"
                      "Signature")
                    '("URL" "Compression" "FileSize" "FileHash"))))
 
diff --git a/guix/scripts/publish.scm b/guix/scripts/publish.scm
index 6e2b4368da..9c83f5183d 100644
--- a/guix/scripts/publish.scm
+++ b/guix/scripts/publish.scm
@@ -58,6 +58,7 @@ (define-module (guix scripts publish)
   #:use-module (guix workers)
   #:use-module (guix store)
   #:use-module ((guix serialization) #:select (write-file))
+  #:use-module (eris)
   #:use-module (zlib)
   #:autoload   (lzlib) (call-with-lzip-output-port
                         make-lzip-output-port)
@@ -146,6 +147,9 @@ (define %default-gzip-compression
   ;; Since we compress on the fly, default to fast compression.
   (compression 'gzip 3))
 
+(define %eris-zstd-compression
+  (compression 'zstd 19))
+
 (define (default-compression type)
   (compression type 3))
 
@@ -324,7 +328,8 @@ (define* (store-item->recutils store-item
 
 (define* (narinfo-string store store-path
                          #:key (compressions (list %no-compression))
-                         (nar-path "nar") (file-sizes '()))
+                         (nar-path "nar") (file-sizes '())
+                         eris-urn)
   "Generate a narinfo key/value string for STORE-PATH; an exception is raised
 if STORE-PATH is invalid.  Produce a URL that corresponds to COMPRESSION.  The
 narinfo is signed with KEY.  NAR-PATH specifies the prefix for nar URLs.
@@ -347,7 +352,7 @@ (define* (narinfo-string store store-path
 StorePath: ~a
 ~{~a~}\
 NarHash: sha256:~a
-NarSize: ~d
+NarSize: ~d~@[~%ERISFormat: application/x-nix-archive+zstd-19~%ERIS: ~a~]
 References: ~a~%"
                              store-path
                              (map (lambda (compression)
@@ -359,7 +364,7 @@ (define* (narinfo-string store store-path
                                                             #:compression
                                                             compression)))
                                   compressions)
-                             hash size references))
+                             hash size eris-urn references))
          ;; Do not render a "Deriver" line if we are rendering info for a
          ;; derivation.  Also do not render a "System" line that would be
          ;; expensive to compute and is currently unused.
@@ -632,6 +637,16 @@ (define (compressed-nar-size compression)
       (and stat
            (cons compression (stat:size stat)))))
 
+  (define (eris-encode-nar compressions)
+    (and (member %eris-zstd-compression compressions)
+         (let* ((nar (nar-cache-file cache item
+                                     #:compression %eris-zstd-compression))
+                (stat (stat nar #f)))
+           (and stat
+                (call-with-input-file nar
+                  (cut eris-encode->string <>
+                       #:block-size %eris-block-size-large))))))
+
   (let ((compression (actual-compressions item compressions)))
 
     (for-each (cut compress-nar cache item <>) compressions)
@@ -650,7 +665,8 @@ (define (compressed-nar-size compression)
                  (display (narinfo-string store item
                                           #:nar-path nar-path
                                           #:compressions compressions
-                                          #:file-sizes sizes)
+                                          #:file-sizes sizes
+                                          #:eris-urn (eris-encode-nar 
compression))
                           port)))
 
              ;; Make the cached narinfo world-readable, contrary to what
-- 
2.34.0