Using recipe revisions and lockfiles

If you don’t want to deploy and maintain your own Artifactory instance, you can isolate your project from changes in upstream remotes, for example ConanCenter, using recipe revisions and lockfiles (please, read linked Conan documentation for more detailed explanation).

Recipe revisions and lockfiles can be used to define exactly the binary you want to use in your project. Even if the recipe is modified and new binaries are generated for the same configurations, existing binaries will exist, you just need to instruct Conan to use them even if new ones are available.

Recipe Revisions

Recipe Revisions are the way to tell Conan to use a specific snapshot of the recipe. It is a hash added to the reference and can be used in Conan at the same place as regular revisions:

In the command line:

conan install openssl/3.0.1@#1955937e88f13a02aa4fdae98c3f9fb8

In a conanfile.txt file:

[requires]
openssl/3.0.1@#1955937e88f13a02aa4fdae98c3f9fb8

In a conanfile.py file:

def requirements(self):
    self.requires("openssl/3.0.1@#1955937e88f13a02aa4fdae98c3f9fb8")

If you use explicit recipe revisions in your project you can be sure that Conan will always use the same recipe revision of those references. You might get new binaries if the same configuration (same packageID) is built again for the same recipe revision, but that is not going to be a compatibility problem.

This might not be enough for some projects, where you want to be sure nothing is modified, not just the revisions you are listing explicitly but also any other transitive dependency, this is what lockfiles are for.

Lockfiles

Lockfiles are files where all the information about requirements is written: recipe revisions, package IDs and package revisions. You can create a lockfile with all the dependencies for your project once you are happy with them, and use that same lockfile with every Conan command. Conan will always build the same graph (the locked one) and will always retrieve the same recipes and binaries.

Warning

Lockfiles have a few known limition that can not be fixed in Conan 1.x, there are exciting improvements coming with Conan 2.0. Please read the documenation linked below for more details.

Then, it would be up to you to generate a new lockfile if you want to introduce new revisions for existing references.

The two basic commands you need to know (full docs here):

Create lockfile from conanfile.txt file:

conan lock create conanfile.txt --lockfile-out=locks/project.lock

Consume a lockfile:

conan install conanfile.txt --lockfile=locks/project.lock

If your project is managing several configurations, you would probably like to have a look to base lockfiles and lockfile bundles in the documentation.