HTTP/HTTPS check

HTTP and HTTPS checks are used to test an HTTP/s endpoint, measuring the uptime and response latency. These checks can also be configured for more advanced tests, like if a site is using a specific version of SSL, for SSL certificate expiration, or if HTTP automatically redirects to HTTPS.

You can also use MultiHTTP checks to test multiple URLs in a single check.

Options

The list of common options to all check types:

Common options

Option	Description
Enabled	Whether the check is enabled or not.
Job name	Refer to the check name. Check metrics include a `job` label with the value of this option.
Target	Target of the check request. Check metrics include an `instance` label with the value of this option.
Probe locations	The locations where the check should run from. Check metrics include a `probe` label with the value of the probe location running the check.
Frequency	The frequency the check should run in seconds. The value can range from 60 to 3600 seconds. Only the `sm_check_info` metric includes the `frequency` label.
Timeout	Maximum execution time for the check. The value can range from 1 to 60 seconds.
Custom labels	(Optional) Custom labels applied to check metrics. Refer to Custom labels for querying instructions.

HTTP checks have additional options, which don’t produce any additional labels in the resulting check metrics.

HTTP settings

Option	Description
Request method	The HTTP method the probe will use.
Request body	The body of the HTTP request.
Request headers	The headers to send with the request.
Compression algorithm	The compression algorithm to expect in the response.
Proxy URL	The URL of the proxy used to connect to the target.
Proxy connect headers	Name/value pairs of headers to send to the proxy.
Publish full set of metrics	Whether to publish additional metrics to create histograms (used for Apdex scores or heatmaps). Default is false to reduce the number of active series.

Compression

If you specify a compression algorithm, the body response is required to contain a header matching that value, and the body itself must be compressed using that algorithm. The check will fail if that’s not the case.

TLS config

Option	Description
Disable target certificate validation	Whether to validate the certificate that is presented.
Server name	The server name used during certificate validation.
CA certificate	The certificate for the certificate authority.
Client certificate	The client certificate to present during authentication.
Client key	The corresponding key for the client certificate.

Authentication

Option	Description
Include bearer authorization header in request	Use bearer authentication.
Include basic authorization header in request	Use basic authentication.

Validation

Option	Description
Valid status codes	Status codes considered as valid responses (defaults to 2xx).
Valid HTTP versions	HTTP versions considered as valid responses.
SSL options	Whether to require or reject SSL. Defaults to ignore.
Regex validations	Set of regular expression validations.

For each regular expression validation, you must specify whether to match a header or the body of the response. In either case, you have to specify a regular expression using Go’s syntax. The logic of the match can be inverted; normally, the check will fail if the header or body matches the provided regular expression, but with invert match selected, the check will fail if the header or body does not match the provided regular expression. For header matches, you can also specify that a missing header doesn’t cause the check to fail.

Advanced options

Option	Description
IP version	The internet protocol version to use (V4, V6, or any).
Follow redirects	Whether to follow redirects or to stop at the first response.
Cache busting query parameter name	The name of the parameter appended to the URL to prevent caching.

Metrics

Checks store their results as Prometheus metrics, including the list of common metrics:

Metric	Description
`probe_all_duration_seconds`	Returns how long the probe took to complete in seconds (histogram).
`probe_duration_seconds`	Returns how long the probe took to complete in seconds.
`probe_all_success`	Displays whether or not the probe was a success (summary).
`probe_success`	Displays whether or not the probe was a success.
`sm_check_info`	Provides information about a single check configuration.

Additionally, HTTP checks produce the following metrics:

Metric	Description
`probe_dns_lookup_all_time_seconds`	Returns the time taken for probe DNS lookup in seconds (histogram).
`probe_dns_lookup_time_seconds`	Returns the time taken for probe DNS lookup in seconds.
`probe_failed_due_to_regex`	Indicates if probe failed due to regular expression.
`probe_http_all_duration_seconds`	Duration of HTTP request by phase, summed over all redirects (histogram).
`probe_http_content_length`	Length of HTTP content response.
`probe_http_duration_seconds`	Duration of HTTP request by phase, summed over all redirects.
`probe_http_redirects`	The number of redirects.
`probe_http_ssl`	Indicates if SSL was used for the final redirect.
`probe_http_status_code`	Response HTTP status code.
`probe_http_uncompressed_body_length`	Length of uncompressed response body.
`probe_http_version`	Returns the version of HTTP of the probe response.
`probe_ip_addr_hash`	Specifies the hash of the IP address. It’s useful to detect if the IP address changes.
`probe_ip_protocol`	Specifies whether probe IP protocol is IPv4 or IPv6.
`probe_ssl_earliest_cert_expiry`	Returns last SSL chain expiry in Unix time.
`probe_ssl_last_chain_expiry_timestamp_seconds`	Returns last SSL chain expiry in timestamp.
`probe_ssl_last_chain_info`	Contains SSL leaf certificate information.
`probe_tls_version_info`	Returns the TLS version used or NaN when unknown.

Limitations

The request body size for HTTP and HTTPS checks is limited to 64KB. Checks that exceed this limitation return the error message “Something went wrong running the check, unexpected EOF.”