prserv: Add read-only mode

[YOCTO #13659]

Signed-off-by: Paul Barker <pbarker@konsulko.com>
[updated for asyncrpc changes]
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

3 files changed, 83 insertions, 31 deletions

diff --git a/lib/prserv/client.py b/lib/prserv/client.py
index 285dce72f..a3f19ddaf 100644
--- a/lib/prserv/client.py
+++ b/lib/prserv/client.py
@@ -32,10 +32,17 @@ class PRAsyncClient(bb.asyncrpc.AsyncClient):
         if response:
             return (response['metainfo'], response['datainfo'])
 
+    async def is_readonly(self):
+        response = await self.send_message(
+            {'is-readonly': {}}
+        )
+        if response:
+            return response['readonly']
+
 class PRClient(bb.asyncrpc.Client):
     def __init__(self):
         super().__init__()
-        self._add_methods('getPR', 'importone', 'export')
+        self._add_methods('getPR', 'importone', 'export', 'is_readonly')
 
     def _get_async_client(self):
         return PRAsyncClient()
diff --git a/lib/prserv/db.py b/lib/prserv/db.py
index cb2a2461e..2710d4a22 100644
--- a/lib/prserv/db.py
+++ b/lib/prserv/db.py
@@ -30,21 +30,29 @@ if sqlversion[0] < 3 or (sqlversion[0] == 3 and sqlversion[1] < 3):
 #
 
 class PRTable(object):
-    def __init__(self, conn, table, nohist):
+    def __init__(self, conn, table, nohist, read_only):
         self.conn = conn
         self.nohist = nohist
+        self.read_only = read_only
         self.dirty = False
         if nohist:
             self.table = "%s_nohist" % table 
         else:
             self.table = "%s_hist" % table 
 
-        self._execute("CREATE TABLE IF NOT EXISTS %s \
-                    (version TEXT NOT NULL, \
-                    pkgarch TEXT NOT NULL,  \
-                    checksum TEXT NOT NULL, \
-                    value INTEGER, \
-                    PRIMARY KEY (version, pkgarch, checksum));" % self.table)
+        if self.read_only:
+            table_exists = self._execute(
+                        "SELECT count(*) FROM sqlite_master \
+                        WHERE type='table' AND name='%s'" % (self.table))
+            if not table_exists:
+                raise prserv.NotFoundError
+        else:
+            self._execute("CREATE TABLE IF NOT EXISTS %s \
+                        (version TEXT NOT NULL, \
+                        pkgarch TEXT NOT NULL,  \
+                        checksum TEXT NOT NULL, \
+                        value INTEGER, \
+                        PRIMARY KEY (version, pkgarch, checksum));" % self.table)
 
     def _execute(self, *query):
         """Execute a query, waiting to acquire a lock if necessary"""
@@ -59,8 +67,9 @@ class PRTable(object):
                 raise exc
 
     def sync(self):
-        self.conn.commit()
-        self._execute("BEGIN EXCLUSIVE TRANSACTION")
+        if not self.read_only:
+            self.conn.commit()
+            self._execute("BEGIN EXCLUSIVE TRANSACTION")
 
     def sync_if_dirty(self):
         if self.dirty:
@@ -75,6 +84,15 @@ class PRTable(object):
             return row[0]
         else:
             #no value found, try to insert
+            if self.read_only:
+                data = self._execute("SELECT ifnull(max(value)+1,0) FROM %s where version=? AND pkgarch=?;" % (self.table),
+                                   (version, pkgarch))
+                row = data.fetchone()
+                if row is not None:
+                    return row[0]
+                else:
+                    return 0
+
             try:
                 self._execute("INSERT INTO %s VALUES (?, ?, ?, (select ifnull(max(value)+1,0) from %s where version=? AND pkgarch=?));"
                            % (self.table,self.table),
@@ -103,6 +121,15 @@ class PRTable(object):
             return row[0]
         else:
             #no value found, try to insert
+            if self.read_only:
+                data = self._execute("SELECT ifnull(max(value)+1,0) FROM %s where version=? AND pkgarch=?;" % (self.table),
+                                   (version, pkgarch))
+                row = data.fetchone()
+                if row is not None:
+                    return row[0]
+                else:
+                    return 0
+
             try:
                 self._execute("INSERT OR REPLACE INTO %s VALUES (?, ?, ?, (select ifnull(max(value)+1,0) from %s where version=? AND pkgarch=?));"
                                % (self.table,self.table),
@@ -128,6 +155,9 @@ class PRTable(object):
             return self._getValueHist(version, pkgarch, checksum)
 
     def _importHist(self, version, pkgarch, checksum, value):
+        if self.read_only:
+            return None
+
         val = None 
         data = self._execute("SELECT value FROM %s WHERE version=? AND pkgarch=? AND checksum=?;" % self.table,
                            (version, pkgarch, checksum))
@@ -152,6 +182,9 @@ class PRTable(object):
         return val
 
     def _importNohist(self, version, pkgarch, checksum, value):
+        if self.read_only:
+            return None
+
         try:
             #try to insert
             self._execute("INSERT INTO %s VALUES (?, ?, ?, ?);"  % (self.table),
@@ -245,19 +278,23 @@ class PRTable(object):
 
 class PRData(object):
     """Object representing the PR database"""
-    def __init__(self, filename, nohist=True):
+    def __init__(self, filename, nohist=True, read_only=False):
         self.filename=os.path.abspath(filename)
         self.nohist=nohist
+        self.read_only = read_only
         #build directory hierarchy
         try:
             os.makedirs(os.path.dirname(self.filename))
         except OSError as e:
             if e.errno != errno.EEXIST:
                 raise e
-        self.connection=sqlite3.connect(self.filename, isolation_level="EXCLUSIVE", check_same_thread = False)
+        uri = "file:%s%s" % (self.filename, "?mode=ro" if self.read_only else "")
+        logger.debug("Opening PRServ database '%s'" % (uri))
+        self.connection=sqlite3.connect(uri, uri=True, isolation_level="EXCLUSIVE", check_same_thread = False)
         self.connection.row_factory=sqlite3.Row
-        self.connection.execute("pragma synchronous = off;")
-        self.connection.execute("PRAGMA journal_mode = MEMORY;")
+        if not self.read_only:
+            self.connection.execute("pragma synchronous = off;")
+            self.connection.execute("PRAGMA journal_mode = MEMORY;")
         self._tables={}
 
     def disconnect(self):
@@ -270,7 +307,7 @@ class PRData(object):
         if tblname in self._tables:
             return self._tables[tblname]
         else:
-            tableobj = self._tables[tblname] = PRTable(self.connection, tblname, self.nohist)
+            tableobj = self._tables[tblname] = PRTable(self.connection, tblname, self.nohist, self.read_only)
             return tableobj
 
     def __delitem__(self, tblname):
diff --git a/lib/prserv/serv.py b/lib/prserv/serv.py
index 1fa4e1766..17ae40967 100644
--- a/lib/prserv/serv.py
+++ b/lib/prserv/serv.py
@@ -18,14 +18,16 @@ PIDPREFIX = "/tmp/PRServer_%s_%s.pid"
 singleton = None
 
 class PRServerClient(bb.asyncrpc.AsyncServerConnection):
-    def __init__(self, reader, writer, table):
+    def __init__(self, reader, writer, table, read_only):
         super().__init__(reader, writer, 'PRSERVICE', logger)
         self.handlers.update({
             'get-pr': self.handle_get_pr,
             'import-one': self.handle_import_one,
             'export': self.handle_export,
+            'is-readonly': self.handle_is_readonly,
         })
         self.table = table
+        self.read_only = read_only
 
     def validate_proto_version(self):
         return (self.proto_version == (1, 0))
@@ -56,16 +58,17 @@ class PRServerClient(bb.asyncrpc.AsyncServerConnection):
         self.write_message(response)
 
     async def handle_import_one(self, request):
-        version = request['version']
-        pkgarch = request['pkgarch']
-        checksum = request['checksum']
-        value = request['value']
+        response = None
+        if not self.read_only:
+            version = request['version']
+            pkgarch = request['pkgarch']
+            checksum = request['checksum']
+            value = request['value']
+
+            value = self.table.importone(version, pkgarch, checksum, value)
+            if value is not None:
+                response = {'value': value}
 
-        value = self.table.importone(version, pkgarch, checksum, value)
-        if value is not None:
-            response = {'value': value}
-        else:
-            response = None
         self.write_message(response)
 
     async def handle_export(self, request):
@@ -83,20 +86,25 @@ class PRServerClient(bb.asyncrpc.AsyncServerConnection):
         response = {'metainfo': metainfo, 'datainfo': datainfo}
         self.write_message(response)
 
+    async def handle_is_readonly(self, request):
+        response = {'readonly': self.read_only}
+        self.write_message(response)
+
 class PRServer(bb.asyncrpc.AsyncServer):
-    def __init__(self, dbfile):
+    def __init__(self, dbfile, read_only=False):
         super().__init__(logger)
         self.dbfile = dbfile
         self.table = None
+        self.read_only = read_only
 
     def accept_client(self, reader, writer):
-        return PRServerClient(reader, writer, self.table)
+        return PRServerClient(reader, writer, self.table, self.read_only)
 
     def _serve_forever(self):
-        self.db = prserv.db.PRData(self.dbfile)
+        self.db = prserv.db.PRData(self.dbfile, read_only=self.read_only)
         self.table = self.db["PRMAIN"]
 
-        logger.debug("Started PRServer with DBfile: %s, Address: %s, PID: %s" %
+        logger.info("Started PRServer with DBfile: %s, Address: %s, PID: %s" %
                      (self.dbfile, self.address, str(os.getpid())))
 
         super()._serve_forever()
@@ -194,7 +202,7 @@ def run_as_daemon(func, pidfile, logfile):
     os.remove(pidfile)
     os._exit(0)
 
-def start_daemon(dbfile, host, port, logfile):
+def start_daemon(dbfile, host, port, logfile, read_only=False):
     ip = socket.gethostbyname(host)
     pidfile = PIDPREFIX % (ip, port)
     try:
@@ -210,7 +218,7 @@ def start_daemon(dbfile, host, port, logfile):
 
     dbfile = os.path.abspath(dbfile)
     def daemon_main():
-        server = PRServer(dbfile)
+        server = PRServer(dbfile, read_only=read_only)
         server.start_tcp_server(host, port)
         server.serve_forever()