FreakyBytes / chksrv

check-service a tool to probe and check the health of network services.

chksrv

check-service a tool to probe and check the health of network services

chksrv is a tool intended to be used in conjunction with other tools (e.g. Minitor) to check the health and availability of network services. One design goal was to provide flexibility of what is checked, without the need for complex bash scripts and piping. Effectively allowing to write one check and then validating mulitple measurements afterwards.

Installation

pip install chksrv

You need at least Python 3.7 to run chksrv.

Usage

Usage:
    chksrv (-h | --help)
    chksrv --version
    chksrv tcp [options] [-p PARAM=VALUE]... [-e EXPR]... HOST PORT
    chksrv ssl [options] [-p PARAM=VALUE]... [-e EXPR]... HOST PORT
    chksrv http [options] [-p PARAM=VALUE]... [-e EXPR]... URL

Options:
    -h --help                     Show this screen.
    --version                     Show version.
    -v --verbose                  Increases verbosity.
    -l --log-level LEVEL          Defines the log verbosity [default: WARN].
    --log-file FILE               Stores all log output in a file.
    -p --parameter PARAM=VALUE    Defines a parameter.
    -e --expects EXPR             Defines an expection expression.
    -r --retry RETRY              Defines the amount of retries [default: 3].
    --timeout TIMEOUT             Defines a timeout for one try in seconds [default: 10].

Modules

TCP

The TCP is one of the most basic check modules. Its purpose is to try to establish a connection to a standard TCP listening socket.

Parameters

ipv6:	Specifies the IPv6 behaviour. Possible values: True only tries to connect to IPv6 False only tries to connect to IPv4 'prefer' tries to connect using IPv6 first, and tries IPv4 if this fails (default) 'fallback' tries to connect using IPv4 first, and falls back to IPv6 if this fails
timeout:	Specifies the socket timeout in seconds

Results

tcp.success:	True if the socket connect succeded
tcp.con.time.perf:	Fractions of seconds it took to establish the socket connection
tcp.con.time.process:	Fractions of seconds of CPU time (system and user) the process used to establish the socket connection
tcp.ipv6:	True if the socket was established using IPv6

SSL

The SSL module is based on the TCP module <module-tcp> and layers a SSL/TLS handshake on top of it, using the Python3 ssl library.

All parameters and results from the TCP module are available in addition

Parameters

ssl.use_default_context:	If set to True the SSL context is created using systems defaults. ssl.protocol and ssl.ciphers will be ignored. (default: 'prefer')
ssl.check_hostname:	If set to True chksrv verifies if the SSL certificate commonName matches the connected hostname. (default: False)
ssl.protocol:	SSL protocol to use. Possible values: tls (default) sslv2 sslv3 tlsv1 tlsv1.1 tlsv1.2
ssl.ciphers:	The cipher suite to use. Must be a valid OpenSSL cipher suite string. (default: ALL)
ssl.verify_mode:	SSL verify mode. cf. ssl.VerifyMode (default: CERT_OPTIONAL)
ssl.verify_flags:	SSL verify flags. cf. ssl.VerifyFlags (default: VERIFY_DEFAULT)
ssl.ca:	Directory or file containing x509 certifcates of trusted Certificate Authorities. By setting it to __sys__ chksr tries to load the system default trusted certificates.

Results

ssl.success:	True if the SSL handshake was successful
ssl.con.cert:	Parsed x509 certificate the server used to authenticate itself
ssl.con.cipher:	Negotiated cipher used to this connection
ssl.con.compression:	Compression algorithm for this connection or None
ssl.con.alpn_protocol:	ALPN protocol selected during the TLS handshake or None
ssl.con.npn_protocol:	NPN protocol selected during the SSL/TLS handshake or None
ssl.con.ssl_version:	Actual SSL protocol version negotiated for this connection or None if no secure connection was established
ssl.con.server_hostname:	Hostname of the server
ssl.con.cert.matches_hostname:	True if the server hostname matches the certificate commonName

HTTP

The HTTP module is intended to be used to check web services, and relies on either the TCP or SSL module to establish the underlying socket connection. Depending if the URL is specified with http:// or https://.

Consequently all parameters from either only the TCP module or both the TCP and SSL module are available in addition

Parameters

http.method:	HTTP method of the request. Possible values: GET (default) HEAD POST PUT DELETE OPTIONS PATCH TRACE
http.body:	Body to attach to the request. (default: None)

Results

http.success:	True if the HTTP request was successful. (Does not evaluate the returned status code)
http.resp.status:	HTTP response status code (numeric)
http.resp.reason:	HTTP response reason (e.g. Found)
http.resp.version:	HTTP version
http.resp.body:	HTTP response body
http.resp.body_length:	Actual size of the HTTP response body. (Does not read Content-Length header)
http.resp.header.*:	Collection of response headers, converted to lower-case snake_case. So the header field Content-Length is available as http.resp.header.content_length. If a header field appears multiple times in the response header (e.g. Set-Cookie) the value is provided as list.