diff options
author | Shea Levy <shea@shealevy.com> | 2014-02-08T05·05-0500 |
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committer | Shea Levy <shea@shealevy.com> | 2014-02-08T05·13-0500 |
commit | 64e23d0a38f316a07cef0960d0ed74a450214283 (patch) | |
tree | 5c1e75efbe703e4163f087cb05356bcaa27a9999 /src/download-via-ssh/download-via-ssh.cc | |
parent | 5671188eb2822b7392a6affa5ebe2f1eb8f521a0 (diff) |
Add download-via-ssh substituter
This substituter connects to a remote host, runs nix-store --serve there, and then forwards substituter commands on to the remote host and sends their results to the calling program. The ssh-substituter-hosts option can be specified as a list of hosts to try. This is an initial implementation and, while it works, it has some limitations: * Only the first host is used * There is no caching of query results (all queries are sent to the remote machine) * There is no informative output (such as progress bars) * Some failure modes may cause unhelpful error messages * There is no concept of trusted-ssh-substituter-hosts Signed-off-by: Shea Levy <shea@shealevy.com>
Diffstat (limited to 'src/download-via-ssh/download-via-ssh.cc')
-rw-r--r-- | src/download-via-ssh/download-via-ssh.cc | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/src/download-via-ssh/download-via-ssh.cc b/src/download-via-ssh/download-via-ssh.cc new file mode 100644 index 000000000000..7adb93e10dfe --- /dev/null +++ b/src/download-via-ssh/download-via-ssh.cc @@ -0,0 +1,129 @@ +#include "shared.hh" +#include "util.hh" +#include "serialise.hh" +#include "archive.hh" +#include "affinity.hh" +#include "globals.hh" + +#include <iostream> +#include <unistd.h> + +using namespace nix; +using std::pair; +using std::cout; +using std::endl; + +// !!! TODO: +// * Respect more than the first host +// * use a database +// * show progress + +static pair<FdSink, FdSource> connect(string conn) { + Pipe to, from; + to.create(); + from.create(); + pid_t child = fork(); + switch (child) { + case -1: + throw SysError("unable to fork"); + case 0: + try { + restoreAffinity(); + if (dup2(to.readSide, STDIN_FILENO) == -1) + throw SysError("dupping stdin"); + if (dup2(from.writeSide, STDOUT_FILENO) == -1) + throw SysError("dupping stdout"); + execlp("ssh" + , "ssh" + , "-x" + , "-T" + , conn.c_str() + , "nix-store --serve" + , NULL); + throw SysError("executing ssh"); + } catch (std::exception & e) { + std::cerr << "error: " << e.what() << std::endl; + } + _exit(1); + } + // If child exits unexpectedly, we'll EPIPE. If we exit unexpectedly, child will + // So no need to keep track of it. + + return pair<FdSink, FdSource>(to.writeSide.borrow(), from.readSide.borrow()); +} + +static void substitute(pair<FdSink, FdSource> & pipes, Path storePath, Path destPath) { + writeString("substitute", pipes.first); + writeString(storePath, pipes.first); + pipes.first.flush(); + restorePath(destPath, pipes.second); + cout << endl; +} + +static void query(pair<FdSink, FdSource> & pipes) { + using std::cin; + writeString("query", pipes.first); + for (string line; getline(cin, line);) { + Strings tokenized = tokenizeString<Strings>(line); + string cmd = tokenized.front(); + writeString(cmd, pipes.first); + tokenized.pop_front(); + foreach (Strings::iterator, i, tokenized) + writeStrings(tokenized, pipes.first); + pipes.first.flush(); + if (cmd == "have") { + PathSet paths = readStrings<PathSet>(pipes.second); + foreach (PathSet::iterator, i, paths) + cout << *i << endl; + } else if (cmd == "info") { + for (Path path = readString(pipes.second); !path.empty(); path = readString(pipes.second)) { + cout << path << endl; + cout << readString(pipes.second) << endl; + PathSet references = readStrings<PathSet>(pipes.second); + cout << references.size() << endl; + foreach (PathSet::iterator, i, references) + cout << *i << endl; + cout << readLongLong(pipes.second) << endl; + cout << readLongLong(pipes.second) << endl; + } + } else + throw Error(format("Unknown substituter query `%1%'") % cmd); + cout << endl; + } + writeString("", pipes.first); +} + +void run(Strings args) +{ + if (args.empty()) + throw UsageError("download-via-ssh requires an argument"); + + if (settings.sshSubstituterHosts.empty()) + return; + + cout << endl; + + pair<FdSink, FdSource> pipes = connect(settings.sshSubstituterHosts.front()); + + Strings::iterator i = args.begin(); + if (*i == "--query") + query(pipes); + else if (*i == "--substitute") + if (args.size() != 3) + throw UsageError("download-via-ssh: --substitute takes exactly two arguments"); + else { + Path storePath = *++i; + Path destPath = *++i; + substitute(pipes, storePath, destPath); + } + else + throw UsageError(format("download-via-ssh: unknown command `%1%'") % *i); +} + +void printHelp() +{ + std::cerr << "Usage: download-via-ssh --query|--substitute store-path dest-path" << std::endl; +} + + +string programId = "download-via-ssh"; |