oe-build-perf-report-email.py: add images as MIME objects

Add images as separate MIME objects instead of directly embedding images
in the html (as base64 encoded pngs). This makes the emails better
suited for certain email servers/clients.

(From OE-Core rev: 6b61126c386a0a7334cdf475d349b830c436ed82)

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/contrib/oe-build-perf-report-email.py

@@ -25,6 +25,7 @@ import socket
 import subprocess
 import sys
 import tempfile
+from email.mime.image import MIMEImage
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 
@@ -111,15 +112,6 @@ def decode_png(infile, outfile):
     subprocess.check_output(['optipng', outfile], stderr=subprocess.STDOUT)
 
 
-def encode_png(pngfile):
-    """Encode png into a <img> html element"""
-    with open(pngfile, 'rb') as f:
-        data = f.read()
-
-    b64_data = base64.b64encode(data)
-    return '<img src="data:image/png;base64,' + b64_data.decode('utf-8') + '">\n'
-
-
 def mangle_html_report(infile, outfile, pngs):
     """Mangle html file into a email compatible format"""
     paste = True
@@ -144,9 +136,7 @@ def mangle_html_report(infile, outfile, pngs):
                     # Replace charts with <img> elements
                     match = re.match('<div id="(?P<id>\w+)"', stripped)
                     if match and match.group('id') in pngs:
-                        #f_out.write('<img src="{}">\n'.format(match.group('id') + '.png'))
-                        png_file = os.path.join(png_dir, match.group('id') + '.png')
-                        f_out.write(encode_png(png_file))
+                        f_out.write('<img src="cid:{}"\n'.format(match.group('id')))
                     else:
                         f_out.write(line)
 
@@ -170,7 +160,7 @@ def scrape_html_report(report, outdir, phantomjs_extra_args=None):
                                 stderr=subprocess.STDOUT)
 
         pngs = []
-        attachments = []
+        images = []
         for fname in os.listdir(tmpdir):
             base, ext = os.path.splitext(fname)
             if ext == '.png':
@@ -178,7 +168,7 @@ def scrape_html_report(report, outdir, phantomjs_extra_args=None):
                 decode_png(os.path.join(tmpdir, fname),
                            os.path.join(outdir, fname))
                 pngs.append(base)
-                attachments.append(fname)
+                images.append(fname)
             elif ext in ('.html', '.htm'):
                 report_file = fname
             else:
@@ -188,11 +178,13 @@ def scrape_html_report(report, outdir, phantomjs_extra_args=None):
         log.debug("Mangling html report file %s", report_file)
         mangle_html_report(os.path.join(tmpdir, report_file),
                            os.path.join(outdir, report_file), pngs)
-        return report_file, attachments
+        return (os.path.join(outdir, report_file),
+                [os.path.join(outdir, i) for i in images])
     finally:
         shutil.rmtree(tmpdir)
 
-def send_email(text_fn, html_fn, subject, recipients, copy=[], blind_copy=[]):
+def send_email(text_fn, html_fn, image_fns, subject, recipients, copy=[],
+               blind_copy=[]):
     """Send email"""
     # Generate email message
     text_msg = html_msg = None
@@ -201,8 +193,16 @@ def send_email(text_fn, html_fn, subject, recipients, copy=[], blind_copy=[]):
             text_msg = MIMEText("Yocto build performance test report.\n" +
                                 f.read(), 'plain')
     if html_fn:
+        html_msg = msg = MIMEMultipart('related')
         with open(html_fn) as f:
-            html_msg = MIMEText(f.read(), 'html')
+            html_msg.attach(MIMEText(f.read(), 'html'))
+        for img_fn in image_fns:
+            # Expect that content id is same as the filename
+            cid = os.path.splitext(os.path.basename(img_fn))[0]
+            with open(img_fn, 'rb') as f:
+                image_msg = MIMEImage(f.read())
+            image_msg['Content-ID'] = '<{}>'.format(cid)
+            html_msg.attach(image_msg)
 
     if text_msg and html_msg:
         msg = MIMEMultipart('alternative')
@@ -251,10 +251,10 @@ def main(argv=None):
 
     try:
         log.debug("Storing email parts in %s", outdir)
-        html_report = None
+        html_report = images = None
         if args.html:
-            scrape_html_report(args.html, outdir, args.phantomjs_args)
-            html_report = os.path.join(outdir, os.path.basename(args.html))
+            html_report, images = scrape_html_report(args.html, outdir,
+                                                     args.phantomjs_args)
 
         if args.to:
             log.info("Sending email to %s", ', '.join(args.to))
@@ -262,7 +262,7 @@ def main(argv=None):
                 log.info("Copying to %s", ', '.join(args.cc))
             if args.bcc:
                 log.info("Blind copying to %s", ', '.join(args.bcc))
-            send_email(args.text, html_report, args.subject,
+            send_email(args.text, html_report, images, args.subject,
                        args.to, args.cc, args.bcc)
     except subprocess.CalledProcessError as err:
         log.error("%s, with output:\n%s", str(err), err.output.decode())