Docker notes--docker swarm function Code Analysis (1)

This is a creation in Article, where the information may have evolved or changed.

Docker 1.12Integrated docker swarm functionality, and its client associated code is located in a api/client/swarm folder. Take docker swarm init the code for the Command ( api/client/swarm/init.go ) as an example:

Const (generatedsecretentropybytes = Generatedsecretbase = approx.//Floor (log (2^128-1, $)) + 1 Maxge  Neratedsecretlength = +) type initoptions struct {swarmoptions listenaddr nodeaddroption//Not a nodeaddroption    Because it has no default port. Advertiseaddr string Forcenewcluster bool}func newinitcommand (dockercli *client. DOCKERCLI) *cobra. Command {opts: = initoptions{listenaddr:newlistenaddroption (),} cmd: = &cobra. command{use: "Init [OPTIONS]", short: "Initialize a Swarm", args:cli. Noargs, Rune:func (cmd *cobra. Command, args []string] Error {return runinit (dockercli, cmd). Flags (), opts)},} Flags: = cmd. Flags () flags. Var (&opts.listenaddr, Flaglistenaddr, "Listen address (format: <ip|interface>[:p ort])") flags. Stringvar (&opts.advertiseaddr, Flagadvertiseaddr, "", "advertised address (format: <ip|interface>[:p ort])" ) flags. Boolvar (&Opts.forcenewcluster, "Force-new-cluster", false, "force create a new cluster from the current state.") Addswarmflags (Flags, &opts.swarmoptions) return Cmd}func runinit (dockercli *client. DOCKERCLI, Flags *pflag. Flagset, opts initoptions) error {client: = Dockercli.client () CTX: = Context. Background () Req: = Swarm. initrequest{ListenAddr:opts.listenAddr.String (), ADVERTISEADDR:OPTS.ADVERTISEADDR, forcenew Cluster:opts.forceNewCluster, Spec:opts.swarmOptions.ToSpec (),} NodeID, err: = client. Swarminit (CTX, req) if err! = Nil {if strings. Contains (Err. Error (), "Could not choose a IP address to advertise") | | Strings. Contains (Err. Error (), "could not find the system ' s IP address") {return errors. New (Err. Error () + "-Specify one with--advertise-addr")} Return err} FMT. fprintf (Dockercli.out (), "Swarm initialized:current node (%s) is now a manager.\n\n", NodeID) If err: = PRintjoincommand (CTX, Dockercli, NodeID, True, false); Err! = Nil {return err} FMT. Fprint (Dockercli.out (), "to add a manager to this swarm, run ' Docker swarm Join-token Manager ' and follow the instructions . \ n ") return nil}

Where client. DOCKERCLI Rep Docker command line client :

DOCKERCLI represents the Docker command line client.//Instances of the client can be returned from Newdockercli.type D OCKERCLI struct {//initializing closure init func () error//ConfigFile has the client configuration file Co Nfigfile *configfile. ConfigFile//In holds the input stream and closer (IO.    Readcloser) for the client. In IO. Readcloser//out holds the output stream (IO.    Writer) for the client. Out IO. Writer//Err holds the error stream (IO.    Writer) for the client. Err io.    Writer//keyfile holds the key file as a string.    KeyFile string//INFD holds the file descriptor of the client ' s STDIN (if valid).    INFD uintptr//OUTFD holds file descriptor of the client ' s STDOUT (if valid). OUTFD uintptr//Isterminalin Indicates whether the client ' s STDIN is a TTY isterminalin bool//Isterminalout in Dicates whether the client ' s STDOUT is a TTY isterminalout bool//client is the HTTP client that performs all API O PeratIons client client. Apiclient//State holds the terminal input state instate *term. State//Outstate holds the terminal output state outstate *term. State}

The client members are engine-api/client , so the above client.SwarmInit code is in engine-api/client/swarm_init.go :

// SwarmInit initializes the Swarm.func (cli *Client) SwarmInit(ctx context.Context, req swarm.InitRequest) (string, error) {    serverResp, err := cli.post(ctx, "/swarm/init", nil, req, nil)    if err != nil {        return "", err    }    var response string    err = json.NewDecoder(serverResp.body).Decode(&response)    ensureReaderClosed(serverResp)    return response, err}