release.sh: better support 3rd party signers

adds binary downloading from website if the specified signer is not one
of the two hardcoded signers with sftp access to the airlock server.
This makes it easier for other signers to run the script and create
signatures for spesmilo/electrum-signatures.

contrib/release.sh

@@ -6,8 +6,9 @@
 # - assumes all keys are available, and signs everything
 # This script, for other builders:
 # - builds all reproducible binaries,
-# - downloads binaries built by the release manager (from airlock), compares and signs them,
-# - and then uploads sigs
+# - downloads binaries built by the release manager (from airlock if SFTPUSER, else from website),
+#   compares and signs them,
+# - and then uploads sigs (if SFTPUSER), else they can be submitted as PR to spesmilo/electrum-signatures
 # Note: the .dmg should be built separately beforehand and copied into dist/
 #       (as it is built on a separate machine)
 #
@@ -57,7 +58,6 @@ if [ -z "$GPGUSER" ]; then
     fail "usage: $0 gpg_username"
 fi
 
-export SSHUSER="$GPGUSER"
 RELEASEMANAGER=""
 if [ "$GPGUSER" == "ThomasV" ]; then
     PUBKEY="--local-user 6694D8DE7BE8EE5631BED9502BD5824B7F9470E6"
@@ -68,6 +68,8 @@ elif [ "$GPGUSER" == "sombernight_releasekey" ]; then
     export SSHUSER=sombernight
 else
     warn "unexpected GPGUSER=$GPGUSER"
+    PUBKEY=""
+    export SSHUSER=""
 fi
 
 
@@ -208,13 +210,41 @@ if [ -z "$RELEASEMANAGER" ] ; then
     rm -rf "$PROJECT_ROOT/dist/releasemanager"
     mkdir --parent "$PROJECT_ROOT/dist/releasemanager"
     cd "$PROJECT_ROOT/dist/releasemanager"
-    # TODO check somehow that RM had finished uploading
-    sftp -oBatchMode=no -b - "$SSHUSER@uploadserver" << !
-       cd electrum-downloads-airlock
-       cd "$VERSION"
-       mget *
-       bye
-!
+
+    if [ -z "$SSHUSER" ]; then
+        info "No SFTP access, downloading binaries from website"
+        BASE_URL="https://download.electrum.org/$VERSION"
+        FILES_TO_DOWNLOAD=(
+            "$tarball"
+            "$srctarball"
+            "$appimage"
+            "$win1"
+            "$win2"
+            "$win3"
+            "$apk1"
+            "$apk2"
+            "$apk3"
+            "$dmg"
+        )
+
+        for filename in "${FILES_TO_DOWNLOAD[@]}"; do
+            if [ ! -f "$filename" ]; then
+                info "Downloading $filename..."
+                wget -q "$BASE_URL/$filename" -O "$filename" || fail "Failed to download $filename"
+            else
+                info "File already exists: $filename"
+            fi
+        done
+    else
+        # TODO check somehow that RM had finished uploading
+        sftp -oBatchMode=no -b - "$SSHUSER@uploadserver" <<-EOF
+           cd electrum-downloads-airlock
+           cd "$VERSION"
+           mget *
+           bye
+EOF
+    fi
+
     # check we have each binary
     test -f "$tarball"    || fail "tarball not found among sftp downloads"
     test -f "$srctarball" || fail "srctarball not found among sftp downloads"
@@ -254,8 +284,14 @@ if [ -z "$RELEASEMANAGER" ] ; then
         signame="$fname.$GPGUSER.asc"
         gpg --sign --armor --detach $PUBKEY --output "$PROJECT_ROOT/dist/sigs/$signame" "$fname"
     done
-    # upload sigs
-    ELECBUILD_UPLOADFROM="$PROJECT_ROOT/dist/sigs/" "$CONTRIB/upload.sh"
+
+    if [ -z "$SSHUSER" ]; then
+        info "Signing successfully, now open a pull request with your signatures to spesmilo/electrum-signatures"
+        exit 0
+    else
+        # upload sigs
+        ELECBUILD_UPLOADFROM="$PROJECT_ROOT/dist/sigs/" "$CONTRIB/upload.sh"
+    fi
 
 else
     # ONLY release manager