Wait strategies

Testcontainers provides a set of wait strategies which help us determine if and when a container is ready to accept requests. Wait strategies are defined for the :wait-for key in the container configuration with the key :wait-strategy determining which strategy to select. The start! function will block until the container is ready and continue processing afterwards.

HTTP Wait Strategy

The HTTP wait strategy will perform an HTTP call according to the following configuration and only continue if the criteria is met.

Parameter	Type	Description
wait-strategy	Keyword	:http
path	String	The HTTP path to access
port	int	The HTTP port to access
method	String	The HTTP method to use (get, post, put...)
status-codes	seq of int	The status codes which mark a successful request
tls	boolean	Should TLS be used?
allow-insecure	boolean	Should insecure HTTP endpoints be trusted?
read-timeout	long	The duration in seconds the HTTP may take
basic-credentials	Map	{:username "User" :password "Password"}
headers	Map	HTTP Headers, e.g. {"Accept" "application/json"}
startup-timeout	long	The duration in seconds the container may take to start

Example:

(tc/create {:image-name    "alpine:3.5"
            :command       ["/bin/sh"
                            "-c"
                            "while true ; do printf 'HTTP/1.1 200 OK\\n\\nyay' | nc -l -p 8080; done"]
            :exposed-ports [8080]
            :wait-for      {:wait-strategy   :http
                            :path            "/"
                            :port            8080
                            :method          "GET"
                            :status-codes    [200]
                            :tls             false
                            :read-timout     5
                            :headers         {"Accept" "text/plain"}
                            :startup-timeout 20}})

Health Wait Strategy

The Health Wait Strategy uses a health check defined in the Dockerfile to determine if the container is ready.

Parameter	Type	Description
wait-strategy	Keyword	:port
startup-timeout	long	The duration in seconds the container may take to start

(tc/create {:image-name    "alpine:3.5"
            :exposed-ports [8080]
            :wait-for      {:wait-strategy   :health
                            :startup-timeout 20}})

Log Wait Strategy

The Log Wait Strategy waits until a certain phrase appears in the Docker containers' log.

Parameter	Type	Description
wait-strategy	Keyword	:log
message	String	A substring of an expected line in the containers log
times	int	The number of times the predicate has to match
startup-timeout	long	The duration in seconds the container may take to start

(tc/create {:image-name    "postgres:12.2"
            :exposed-ports [5432]
            :env-vars      {"POSTGRES_PASSWORD" "pw"}
            :wait-for      {:wait-strategy   :log
                            :message         "accept connections"
                            :startup-timeout 10}})

Port Wait Strategy

This strategy is the default selcted by Testcontainers if no wait strategy was defined. It waits for the first port in the containers port mapping to be opened. It does not accept any parameters beside the startup-timeout

Parameter	Type	Description
wait-strategy	Keyword	:port
startup-timeout	long	The duration in seconds the container may take to start

(tc/create {:image-name    "postgres:12.2"
            :exposed-ports [5432]
            :env-vars      {"POSTGRES_PASSWORD" "pw"}
            :wait-for      {:wait-strategy :port}})