chore: better support for both versions, symlink default to v3 on new image

Author: samrose

ansible/tasks/setup-wal-g.yml

@@ -36,7 +36,7 @@
 - name: Create symlink for wal-g from Nix profile to /usr/local/bin
   ansible.builtin.file:
     src: /home/wal-g/.nix-profile/bin/wal-g-2
-    dest: /usr/local/bin/wal-g
+    dest: /usr/local/bin/wal-g-v2
     state: link
     force: yes  # This will replace existing file/symlink if it exists
   become: yes   # Need sudo to write to /usr/local/bin
@@ -51,6 +51,15 @@
   become: yes   # Need sudo to write to /usr/local/bin
   when: stage2_nix
 
+- name: Create symlink to make wal-g-v3 the default wal-g
+  ansible.builtin.file:
+    src: /usr/local/bin/wal-g-v3
+    dest: /usr/local/bin/wal-g
+    state: link
+    force: yes
+  become: yes
+  when: stage2_nix
+
 - name: Create /etc/wal-g/config.json
   file:
     path: /etc/wal-g/config.json

nix/wal-g.nix

@@ -44,17 +44,22 @@ let
       ];
 
       postInstall = ''
-        mv $out/bin/pg $out/bin/wal-g
-        installShellCompletion --cmd wal-g \
-          --bash <($out/bin/wal-g completion bash) \
-          --zsh <($out/bin/wal-g completion zsh)
+        mv $out/bin/pg $out/bin/wal-g-${majorVersion}
+        
+        # Create version-specific completions
+        mkdir -p $out/share/bash-completion/completions
+        $out/bin/wal-g-${majorVersion} completion bash > $out/share/bash-completion/completions/wal-g-${majorVersion}
+        
+        mkdir -p $out/share/zsh/site-functions
+        $out/bin/wal-g-${majorVersion} completion zsh > $out/share/zsh/site-functions/_wal-g-${majorVersion}
+        
       '';
 
       meta = with lib; {
         homepage = "https://github.com/wal-g/wal-g";
         license = licenses.asl20;
         description = "Archival restoration tool for PostgreSQL";
-        mainProgram = "wal-g";
+        mainProgram = "wal-g-${majorVersion}";
         maintainers = [ samrose ];
       };
     };
@@ -75,4 +80,4 @@ in
     vendorHash = "sha256-YDLAmRfDl9TgbabXj/1rxVQ052NZDg3IagXVTe5i9dw=";
     majorVersion = "3";
   };
-}
+}