Do not fail if javascript lib is online and no Internet (#101)

  - Fixed behavior of the `url_exists()` function
  - Added log levels (Warning)
  - Documented the change

CHANGELOG.md

@@ -4,6 +4,16 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 1.1.2, 2024-09-05
+
+Changed: If the `javascript` parameter starts with http(s) and no Internet
+access is available, a WARNING is now issued
+(mkdocs no longer fails with an exception).
+
+## 1.1.1, 2023-09-26
+
+Fixed: Bug with local javascript library 
+
 ## 1.1.0, 2023-09-01
 
 Added: Parameter `javascript` in config file for optionally specifying the

mermaid2/util.py

@@ -22,11 +22,43 @@
     log.addFilter(warning_filter)
 
 MERMAID_LABEL = "MERMAID2  -" # plugin's signature label
-def info(*args) -> str:
-    "Write information on the console, preceded by the signature label"
+
+
+TRACE_LEVELS = {
+    'debug'   : logging.DEBUG,
+    'info'    : logging.INFO,
+    'warning' : logging.WARNING,
+    'error'   : logging.ERROR,
+    'critical': logging.CRITICAL
+}
+
+def trace(*args, level:str='info'):
+    """
+    General purpose print function, as trace,
+    for the mkdocs-macros framework;
+    it will appear unless --quiet option is activated.
+
+    The level is 'debug', 'info', 'warning', 'error' or 'critical'.
+    """
     args = [MERMAID_LABEL] + [str(arg) for arg in args]
     msg = ' '.join(args)
-    log.info(msg)
+    try:
+        log.log(TRACE_LEVELS[level], msg)
+    except KeyError:
+        raise ValueError("Unknown level '%s' %s" % (level, 
+                                                  tuple(TRACE_LEVELS.keys())
+                                                  )
+                            )
+    return msg
+
+
+
+def info(*args) -> str:
+    "Write information on the console, preceded by the signature label"
+    # args = [MERMAID_LABEL] + [str(arg) for arg in args]
+    # msg = ' '.join(args)
+    # log.info(msg)
+    return trace(*args)
 
 # -------------------
 # Paths and URLs
@@ -45,8 +77,13 @@ def libname(lib:str) -> str:
 def url_exists(url:str, local_base_dir:str='') -> bool:
     "Checks that a url exists"
     if url.startswith('http'):
-        request = requests.get(url)
-        return request.status_code == 200
+        try:
+            request = requests.get(url)
+            return request.status_code == 200
+        except requests.exceptions.RequestException as e:
+            trace("Cannot check URL, no Internet access? (%s):\n\n%s" % (url, e),
+                  level='warning')
+            return True
     else:
         pathname = os.path.join(local_base_dir, url)
         return os.path.exists(pathname)

test/http_lib/docs/index.md

@@ -0,0 +1,39 @@
+# Mermaid test (simple)
+
+## Mermaid usual
+This is a test of Mermaid:
+
+```mermaid
+graph TD
+    hello --> world
+    world --> world2
+```
+
+> If you don't see a graph here, it's broken.
+
+## Git Graph
+This is a test of Git Graph: 
+
+```mermaid
+gitGraph
+    commit
+    commit
+    branch develop
+    checkout develop
+    commit
+    commit
+    checkout main
+    merge develop
+    commit
+    commit
+```
+
+
+## Normal fences
+This is usual fenced code (with no highlighting)
+
+```python
+for page in pages:
+    page.read()
+```
+

test/http_lib/docs/second.md

@@ -0,0 +1,25 @@
+# Second page
+Testing special cases
+
+## Wrong diagram
+
+```mermaid
+graph FG
+A[Client] 
+```
+
+## Correct
+
+```mermaid
+graph TD
+A[Client] --> B[Load Balancer]
+```
+
+## Other
+
+```mermaid
+graph TD
+  A[Client] --> B[Load Balancer]
+  B --> C[Server01]
+  B --> D[Server02]
+```

test/http_lib/mkdocs.yml

@@ -0,0 +1,17 @@
+site_name: Mermaid test (simple, with local specified library)
+site_description: Test for mermaid
+docs_dir: docs # indispensable or readthedocs will fail
+theme: readthedocs # you may want to try windmill?
+
+
+nav:
+  - Main: index.md
+  - Second: second.md
+
+plugins:
+  - search
+  - mermaid2:
+      javascript: https://cdn.jsdelivr.net/npm/mermaid@11/dist/mermaid.esm.min.mjs   
+
+
+

webdoc/docs/library.md

@@ -66,6 +66,7 @@ changing the version number to determine the version you want
 https://cdn.jsdelivr.net/npm/mermaid@10.2.0/dist/mermaid.min.js
 ```
 
+
 !!! Note
     No explicit call to `mermaid.initialize()` is required, since it is
     automatically inserted by the plugin.
@@ -80,6 +81,14 @@ https://cdn.jsdelivr.net/npm/mermaid@10.2.0/dist/mermaid.min.js
     on its ownlwill definitely **not** work, since there will be broken
     links.
 
+!!! Warning "Behavior in case of incorrect URL/no Internet access"
+    1. An incorrect URL will cause an error that aborts MkDocs.
+    2. If the address starts with http(s) and no Internet access
+       is available at time of compile, MkDocs-Mermaid will continue and issue
+       a WARNING. That behavior is for containers that do not
+       have necessarily have Internet access at compile time
+       (however, if you want to abort
+       in that case use the strict mode: `mkdocs build --strict`.
 
 ## Using `extra_javascript`