Introduce LSP Support

This addresses mbj4668#903

Signed-off-by: Siddharth Sharma <[email protected]>

.editorconfig

@@ -0,0 +1,14 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.py]
+indent_style = space
+indent_size = 4

pyang/context.py

@@ -141,17 +141,18 @@ def add_parsed_module(self, module):
 
         return module
 
-    def del_module(self, module):
+    def del_module(self, module, revision=None):
         """Remove a module from the context"""
-        rev = util.get_latest_revision(module)
-        del self.modules[(module.arg, rev)]
+        if revision is None:
+            revision = util.get_latest_revision(module)
+        del self.modules[(module.arg, revision)]
 
     def get_module(self, modulename, revision=None):
         """Return the module if it exists in the context"""
         if revision is None and modulename in self.revs:
             (revision, _handle) = self._get_latest_rev(self.revs[modulename])
         if revision is not None:
-            if (modulename,revision) in self.modules:
+            if (modulename, revision) in self.modules:
                 return self.modules[(modulename, revision)]
         else:
             return None

pyang/lsp/__init__.py

@@ -0,0 +1,4 @@
+"""pyang library to serve Microsoft LSP"""
+
+__version__ = "0.0.1"
+__date__ = "2024-05-10"

pyang/lsp/server.py

@@ -0,0 +1,211 @@
+"""pyang LSP handling"""
+
+from __future__ import absolute_import
+import optparse
+from pathlib import Path
+
+from pyang import error
+from pyang import context
+from pyang import plugin
+from pyang import syntax
+
+from lsprotocol import types as lsp
+
+from pygls.server import LanguageServer
+
+SERVER_NAME = "pyangls"
+SERVER_VERSION = "v0.1"
+
+SERVER_MODE_IO = "io"
+SERVER_MODE_TCP = "tcp"
+SERVER_MODE_WS = "ws"
+supported_modes = [
+    SERVER_MODE_IO,
+    SERVER_MODE_TCP,
+    SERVER_MODE_WS,
+]
+default_mode = SERVER_MODE_IO
+default_host = "127.0.0.1"
+default_port = 2087
+
+class PyangLanguageServer(LanguageServer):
+    def __init__(self, *args):
+        self.ctx : context.Context
+        super().__init__(*args)
+
+pyangls = PyangLanguageServer(SERVER_NAME, SERVER_VERSION)
+
+def _validate(ls: LanguageServer,
+              params: lsp.DidChangeTextDocumentParams | lsp.DidOpenTextDocumentParams):
+    ls.show_message_log("Validating YANG...")
+
+    text_doc = ls.workspace.get_text_document(params.text_document.uri)
+    source = text_doc.source
+
+    pyangls.ctx.errors = []
+    modules = []
+    diagnostics = []
+    if source:
+        m = syntax.re_filename.search(Path(text_doc.filename).name)
+        if m is not None:
+            name, rev, in_format = m.groups()
+            module = pyangls.ctx.get_module(name, rev)
+            if module is not None:
+                pyangls.ctx.del_module(module)
+            module = pyangls.ctx.add_module(text_doc.path, source,
+                                            in_format, name, rev,
+                                            expect_failure_error=False,
+                                            primary_module=True)
+        else:
+            module = pyangls.ctx.add_module(text_doc.path, source,
+                                            primary_module=True)
+        if module is not None:
+            modules.append(module)
+            p : plugin.PyangPlugin
+            for p in plugin.plugins:
+                p.pre_validate_ctx(pyangls.ctx, modules)
+
+            pyangls.ctx.validate()
+            module.prune()
+
+        diagnostics = build_diagnostics()
+
+    ls.publish_diagnostics(text_doc.uri, diagnostics)
+
+def build_diagnostics():
+    """Builds lsp diagnostics from pyang context"""
+    diagnostics = []
+
+    for epos, etag, eargs in pyangls.ctx.errors:
+        msg = error.err_to_str(etag, eargs)
+        # pyang just stores line context, not keyword/argument context
+        start_line = epos.line - 1
+        start_col = 0
+        end_line = epos.line - 1
+        end_col = 1
+        def level_to_severity(level):
+            if level == 1 or level == 2:
+                return lsp.DiagnosticSeverity.Error
+            elif level == 3:
+                return lsp.DiagnosticSeverity.Warning
+            elif level == 4:
+                return lsp.DiagnosticSeverity.Information
+            else:
+                return None
+        d = lsp.Diagnostic(
+            range=lsp.Range(
+                start=lsp.Position(line=start_line, character=start_col),
+                end=lsp.Position(line=end_line, character=end_col),
+            ),
+            message=msg,
+            severity=level_to_severity(error.err_level(etag)),
+            code=etag,
+            source=SERVER_NAME,
+        )
+
+        diagnostics.append(d)
+
+    return diagnostics
+
+
+@pyangls.feature(
+    lsp.TEXT_DOCUMENT_DIAGNOSTIC,
+    lsp.DiagnosticOptions(
+        identifier="pyangls",
+        inter_file_dependencies=True,
+        workspace_diagnostics=True,
+    ),
+)
+def text_document_diagnostic(
+    params: lsp.DocumentDiagnosticParams,
+) -> lsp.DocumentDiagnosticReport:
+    """Returns diagnostic report."""
+    return lsp.RelatedFullDocumentDiagnosticReport(
+        items=_validate(pyangls, params),
+        kind=lsp.DocumentDiagnosticReportKind.Full,
+    )
+
+
+@pyangls.feature(lsp.WORKSPACE_DIAGNOSTIC)
+def workspace_diagnostic(
+    params: lsp.WorkspaceDiagnosticParams,
+) -> lsp.WorkspaceDiagnosticReport:
+    """Returns diagnostic report."""
+    documents = pyangls.workspace.text_documents.keys()
+
+    if len(documents) == 0:
+        items = []
+    else:
+        first = list(documents)[0]
+        document = pyangls.workspace.get_text_document(first)
+        items = [
+            lsp.WorkspaceFullDocumentDiagnosticReport(
+                uri=document.uri,
+                version=document.version,
+                items=_validate(pyangls, params),
+                kind=lsp.DocumentDiagnosticReportKind.Full,
+            )
+        ]
+
+    return lsp.WorkspaceDiagnosticReport(items=items)
+
+
+@pyangls.feature(lsp.TEXT_DOCUMENT_DID_CHANGE)
+def did_change(ls: LanguageServer, params: lsp.DidChangeTextDocumentParams):
+    """Text document did change notification."""
+
+    _validate(ls, params)
+
+
+@pyangls.feature(lsp.TEXT_DOCUMENT_DID_CLOSE)
+def did_close(ls: PyangLanguageServer, params: lsp.DidCloseTextDocumentParams):
+    """Text document did close notification."""
+    ls.show_message("Text Document Did Close")
+
+
+@pyangls.feature(lsp.TEXT_DOCUMENT_DID_OPEN)
+async def did_open(ls: LanguageServer, params: lsp.DidOpenTextDocumentParams):
+    """Text document did open notification."""
+    ls.show_message("Text Document Did Open")
+    _validate(ls, params)
+
+
+@pyangls.feature(lsp.TEXT_DOCUMENT_INLINE_VALUE)
+def inline_value(params: lsp.InlineValueParams):
+    """Returns inline value."""
+    return [lsp.InlineValueText(range=params.range, text="Inline value")]
+
+
+def add_opts(optparser: optparse.OptionParser):
+    optlist = [
+        # use capitalized versions of std options help and version
+        optparse.make_option("--lsp-mode",
+                             dest="pyangls_mode",
+                             default=default_mode,
+                             metavar="LSP_MODE",
+                             help="Provide LSP Service in this mode" \
+                             "Supported LSP server modes are: " +
+                             ', '.join(supported_modes)),
+        optparse.make_option("--lsp-host",
+                             dest="pyangls_host",
+                             default=default_host,
+                             metavar="LSP_HOST",
+                             help="Bind LSP Server to this address"),
+        optparse.make_option("--lsp-port",
+                             dest="pyangls_port",
+                             type="int",
+                             default=default_port,
+                             metavar="LSP_PORT",
+                             help="Bind LSP Server to this port"),
+        ]
+    g = optparser.add_option_group("LSP Server specific options")
+    g.add_options(optlist)
+
+def start_server(optargs, ctx: context.Context):
+    pyangls.ctx = ctx
+    if optargs.pyangls_mode == SERVER_MODE_TCP:
+        pyangls.start_tcp(optargs.pyangls_host, optargs.pyangls_port)
+    elif optargs.pyangls_mode == SERVER_MODE_WS:
+        pyangls.start_ws(optargs.pyangls_host, optargs.pyangls_port)
+    else:
+        pyangls.start_io()

pyang/scripts/pyang_tool.py

@@ -5,7 +5,6 @@
 import optparse
 import io
 import shutil
-import codecs
 from pathlib import Path
 
 import pyang
@@ -15,8 +14,8 @@
 from pyang import hello
 from pyang import context
 from pyang import repository
-from pyang import statements
 from pyang import syntax
+from pyang.lsp import server as pyangls
 
 
 def run():
@@ -131,6 +130,10 @@ def run():
                              dest="format",
                              help="Convert to FORMAT.  Supported formats " \
                              "are: " +  ', '.join(fmts)),
+        optparse.make_option("-l", "--lsp",
+                             dest="lsp",
+                             action="store_true",
+                             help="Run as LSP server instead of CLI tool."),
         optparse.make_option("-o", "--output",
                              dest="outfile",
                              help="Write the output to OUTFILE instead " \
@@ -218,6 +221,7 @@ def run():
     optparser.version = '%prog ' + pyang.__version__
     optparser.add_options(optlist)
 
+    pyangls.add_opts(optparser)
     for p in plugin.plugins:
         p.add_opts(optparser)
 
@@ -268,6 +272,9 @@ def run():
     ctx.strict = o.strict
     ctx.max_status = o.max_status
 
+    if o.lsp:
+        pyangls.start_server(o, ctx)
+
     # make a map of features to support, per module
     if o.hello:
         for mn, rev in hel.yang_modules():

setup.py

@@ -60,7 +60,7 @@ def run_commands(self):
       " Provides a framework for plugins that can convert YANG modules" + \
       "to other formats.",
       url='https://github.com/mbj4668/pyang',
-      install_requires = ["lxml"],
+      install_requires = ["lxml", "pygls"],
       license='BSD',
       classifiers=[
             'Development Status :: 5 - Production/Stable',
@@ -82,7 +82,7 @@ def run_commands(self):
               'json2xml = pyang.scripts.json2xml:main',
           ]
       },
-      packages=['pyang', 'pyang.plugins', 'pyang.scripts', 'pyang.translators', 'pyang.transforms'],
+      packages=['pyang', 'pyang.plugins', 'pyang.scripts', 'pyang.translators', 'pyang.transforms', 'pyang.lsp'],
       data_files=[
             ('share/man/man1', man1),
             ('share/yang/modules/iana', modules_iana),