[Bug 1847216] [NEW] motd-news only works with one URL even though docs say mutiple URLs can be configured

[Prasad]

Public bug reported:

The motd-news script etc/update-motd/50-motd-news
the following section

```
# Loop over any configured URLs
for u in $URLS; do
        # Ensure https:// protocol, for security reasons
        case $u in
                https://*)
                        true
                ;;
                https://motd.ubuntu.com)
                        u="$u/$codename/$arch"
                ;;
                *)
                        continue
                ;;
        esac
        # If we're forced, set the wait to much higher (1 minute)
        [ "$FORCED" = "1" ] && WAIT=60
        # Fetch and print the news motd
        if curl --connect-timeout "$WAIT" --max-time "$WAIT" -A "$USER_AGENT" -o- "$u" >"$NEWS" 2>"$ERR"; then
                echo
                # At most, 10 lines of text, remove control characters, print at most 80 characters per line
                safe_print "$NEWS"
                # Try to update the cache
                safe_print "$NEWS" 2>/dev/null >$CACHE || true
        else
                : > "$CACHE"
        fi
done

```

As you can see the $CACHE gets overwritten if multiple URLs are
configured in /etc/default/motd-news

/etc/default/motd-news has
```
# Configure the source of dynamic MOTD news
# White space separated list of 0 to many news services
# For security reasons, these must be https
# and have a valid certificate
# Canonical runs a service at motd.ubuntu.com, and you
# can easily run one too
URLS="https://motd.ubuntu.com"

```

** Affects: base-files (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: motd

** Description changed:

- The motd-news script etc/update-motd/50-motd-news 
+ The motd-news script etc/update-motd/50-motd-news
  the following section
  
  ```
  # Loop over any configured URLs
  for u in $URLS; do
-         # Ensure https:// protocol, for security reasons
-         case $u in
-                 https://*)
-                         true
-                 ;;
-                 https://motd.ubuntu.com)
-                         u="$u/$codename/$arch"
-                 ;;
-                 *)
-                         continue
-                 ;;
-         esac
-         # If we're forced, set the wait to much higher (1 minute)
-         [ "$FORCED" = "1" ] && WAIT=60
-         # Fetch and print the news motd
-         if curl --connect-timeout "$WAIT" --max-time "$WAIT" -A "$USER_AGENT" -o- "$u" >"$NEWS" 2>"$ERR"; then
-                 echo
-                 # At most, 10 lines of text, remove control characters, print at most 80 characters per line
-                 safe_print "$NEWS"
-                 # Try to update the cache
-                 safe_print "$NEWS" 2>/dev/null >$CACHE || true
-         else
-                 : > "$CACHE"
-         fi
+         # Ensure https:// protocol, for security reasons
+         case $u in
+                 https://*)
+                         true
+                 ;;
+                 https://motd.ubuntu.com)
+                         u="$u/$codename/$arch"
+                 ;;
+                 *)
+                         continue
+                 ;;
+         esac
+         # If we're forced, set the wait to much higher (1 minute)
+         [ "$FORCED" = "1" ] && WAIT=60
+         # Fetch and print the news motd
+         if curl --connect-timeout "$WAIT" --max-time "$WAIT" -A "$USER_AGENT" -o- "$u" >"$NEWS" 2>"$ERR"; then
+                 echo
+                 # At most, 10 lines of text, remove control characters, print at most 80 characters per line
+                 safe_print "$NEWS"
+                 # Try to update the cache
+                 safe_print "$NEWS" 2>/dev/null >$CACHE || true
+         else
+                 : > "$CACHE"
+         fi
  done
  
  ```
  
  As you can see the $CACHE gets overwritten if multiple URLs are
  configured in /etc/default/motd-news
  
  /etc/default/motd-news has
  ```
  # Configure the source of dynamic MOTD news
  # White space separated list of 0 to many news services
  # For security reasons, these must be https
  # and have a valid certificate
  # Canonical runs a service at motd.ubuntu.com, and you
  # can easily run one too
- URLS="https://tprasadtp.github.io/motd/spacex/upcoming https://tprasadtp.github.io/motd/nasa/apod"
+ URLS="https://motd.ubuntu.com"
  
  ```

-- 
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https://bugs.launchpad.net/bugs/1847216

Title:
  motd-news only works with one URL even though docs say mutiple URLs
  can be configured

Status in base-files package in Ubuntu:
  New

Bug description:
  The motd-news script etc/update-motd/50-motd-news
  the following section

  ```
  # Loop over any configured URLs
  for u in $URLS; do
          # Ensure https:// protocol, for security reasons
          case $u in
                  https://*)
                          true
                  ;;
                  https://motd.ubuntu.com)
                          u="$u/$codename/$arch"
                  ;;
                  *)
                          continue
                  ;;
          esac
          # If we're forced, set the wait to much higher (1 minute)
          [ "$FORCED" = "1" ] && WAIT=60
          # Fetch and print the news motd
          if curl --connect-timeout "$WAIT" --max-time "$WAIT" -A "$USER_AGENT" -o- "$u" >"$NEWS" 2>"$ERR"; then
                  echo
                  # At most, 10 lines of text, remove control characters, print at most 80 characters per line
                  safe_print "$NEWS"
                  # Try to update the cache
                  safe_print "$NEWS" 2>/dev/null >$CACHE || true
          else
                  : > "$CACHE"
          fi
  done

  ```

  As you can see the $CACHE gets overwritten if multiple URLs are
  configured in /etc/default/motd-news

  /etc/default/motd-news has
  ```
  # Configure the source of dynamic MOTD news
  # White space separated list of 0 to many news services
  # For security reasons, these must be https
  # and have a valid certificate
  # Canonical runs a service at motd.ubuntu.com, and you
  # can easily run one too
  URLS="https://motd.ubuntu.com"

  ```

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